Sound Design at Edinburgh Napier University

Category: Psychoacoustics

  • Why Does Game Audio Matter? Professor Lennart Nacke on Playability, Player Experience, and the Psychology of Sound

    Professor Lennart Nacke

    How much would a game change if you turned the sound off?

    Many players might be tempted to answer very little. Graphics dominate marketing campaigns, technical demonstrations and online discussion. Higher resolutions, realistic lighting and increasingly detailed worlds are often presented as the defining characteristics of modern games. Sound, by comparison, can seem almost secondary. It accompanies the experience, but rarely receives the same attention. If forced to prioritise one feature over another, many players would probably choose visual quality long before they chose audio.

    Everyday experience suggests something rather different. Silence a racing game and judging speed suddenly becomes more difficult. Remove the weapon sounds from a first-person shooter and every encounter feels strangely detached from the player’s actions. Eliminate footsteps, environmental ambience or warning cues and even familiar games begin to feel oddly incomplete. The mechanics have not changed. The graphics remain identical. Objectives, controls and level design are exactly as they were before. And yet something fundamental has disappeared. If sound is supposedly one of the least important elements of a game, why does its absence change the experience so profoundly?

    That paradox formed the starting point of Professor Lennart Nacke’s online guest lecture for Edinburgh Napier University. Drawing on research spanning human-computer interaction, game studies and psychophysiology, Professor Nacke explored a deceptively simple question: what role does sound actually play in the experience of playing a game? At the time of the lecture, he was Research Director of the HCI Games Group and preparing to join the University of Waterloo, where his work continued to investigate player experience, physiological interaction and the design of engaging interactive systems.

    One of the first findings he discussed appeared, at first glance, to reinforce the common assumption that audio matters relatively little. Survey research suggested that players ranked sound below features such as graphics and, perhaps most significantly, playability when asked to identify the most important qualities of a game. Many observers interpreted this as evidence that audio simply was not a priority. Professor Nacke saw something quite different. His question was not whether sound mattered. It was whether players had misunderstood what sound was actually contributing.

    Viewed from that perspective, playability becomes much more than responsive controls or balanced mechanics. It is the continuous conversation between player and game. Every action produces a consequence. Every consequence communicates something back to the player, guiding the next decision. Much of that conversation takes place through sound. A weapon firing, footsteps approaching from behind, an engine changing pitch during acceleration or the subtle cue confirming a successful interaction all provide information that helps players understand both the game world and their own actions within it. Sound does considerably more than create atmosphere. It helps make games playable.

    This also explains why players often underestimate its importance. Rhythm games and audio-only games make sound impossible to ignore, placing it at the centre of the experience. Conventional games achieve almost the opposite effect. Audio works so seamlessly alongside graphics, animation and interaction that its contribution becomes largely invisible. Only when it disappears do players recognise how much guidance it had been providing all along. Feedback becomes less immediate. Decisions become less confident. Successes feel less satisfying, while failures become harder to interpret. Sound is not simply something players hear. It is one of the ways games teach players how to play.

    By the time Professor Nacke moved from the history of game audio towards his own research, the lecture had already shifted onto much firmer ground. The question was no longer whether sound made games more entertaining. It was whether sound quietly underpinned many of the qualities players described as good game design. That possibility led naturally towards psychology, player experience and a series of experiments designed to investigate whether sound changes not only what players hear, but also how they understand and navigate interactive worlds.

    If sound helps make games playable, the next question becomes unavoidable. How does it do that? A racing game does not become easier simply because its engine sounds more realistic, nor does a first-person shooter become more engaging merely through louder explosions. Something more fundamental is taking place. Sound continually provides information that helps players interpret the world around them, anticipate events and judge the consequences of their own actions. Without that information, interaction becomes less certain, even when every visual element remains exactly the same.

    Feedback lies at the heart of this process. Every time players press a button, move a character or perform an action, the game responds. Some responses are visual, others are physical through a controller, and many arrive through sound. Together they form a continuous exchange between player and system. Rather than simply confirming that something has happened, effective feedback helps players understand what happened, why it happened and what they should do next. Viewed in this way, playability becomes inseparable from communication.

    Professor Nacke argued that this relationship between sound and feedback has often been underestimated. Discussions of game audio frequently focus on music, realism or cinematic atmosphere, all of which undoubtedly influence the player’s experience. Yet those aspects represent only part of audio’s contribution. Equally important are the sounds that players rarely think about at all. Footsteps revealing an approaching opponent, the subtle cue confirming that an object has been collected, the changing rhythm of a weapon, the shift in an engine’s pitch or the warning that danger is just beyond the edge of the screen all guide behaviour long before players consciously reflect upon them. The most valuable sounds are often the ones that disappear into the act of playing itself.

    Some games make this communicative role impossible to miss. Rhythm games such as PaRappa the Rapper, Dance Dance Revolution, Guitar Hero and Rock Band place sound at the centre of interaction. Players succeed only by listening carefully and responding with precise timing. Performance is inseparable from audio. Professor Nacke observed that these games introduced a strongly performative dimension in which rhythm, musical timing and vocal control become the mechanics of play rather than decorative additions to it.

    Most conventional games appear very different, yet the distinction is not quite as large as it first seems. Action games, strategy games and multiplayer titles rarely ask players to perform music, but they still depend upon continual interpretation of auditory information. Experienced players often react to sounds almost automatically, recognising threats, opportunities and changing situations without consciously analysing each cue. Learning to play therefore involves learning a game’s sonic language alongside its visual and mechanical systems.

    Audio-only games expose another assumption that many players rarely question. Remove the graphics from most games and many people expect the experience to collapse. Yet audio games communicate entire worlds through hearing alone. Developed partly to improve accessibility for players who cannot rely on conventional visual interfaces, they demonstrate that sound can convey location, movement, interaction and progress with remarkable effectiveness when designed carefully enough. Eliminating graphics does not eliminate gameplay. It simply requires designers to think much more carefully about how information is communicated.

    Taken together, these examples gradually reshape the original question. Earlier, the lecture asked whether sound contributes to playability. By this point, the discussion suggested something stronger. Playability may itself depend upon the quality of communication between player and game, and sound is one of its most important languages. If that proposition is correct, it should also be possible to investigate it scientifically. Professor Nacke’s own research set out to discover whether those ideas could be measured as rigorously as they could be experienced.

    A persuasive theory is only the beginning. Can the contribution of sound actually be measured? It is one thing to argue that players rely upon audio when navigating a virtual world. Demonstrating that relationship through rigorous research is considerably more demanding. Professor Nacke devoted the latter part of his lecture to exactly this challenge, describing an experiment that attempted to move beyond intuition and examine whether sound produces measurable changes in the player experience.

    Rather than relying solely upon interviews or personal opinion, the study combined subjective evaluations with physiological measurement. Participants played Half-Life 2 under different audio conditions while researchers recorded indicators such as heart rate and skin conductance alongside established player experience questionnaires. Bringing these different forms of evidence together reflected a broader ambition within human-computer interaction. If engagement, immersion or enjoyment genuinely change when sound changes, perhaps those differences should be visible not only in what players report afterwards, but also in the body’s physiological responses during play.

    The initial results appeared disappointing. The physiological measures revealed remarkably little difference between the experimental conditions. Heart rate and skin conductance remained far more stable than expected, suggesting that the presence or absence of audio did not produce the clear biological distinctions the researchers had anticipated. Judged solely on those measurements, it would have been tempting to conclude that sound contributed relatively little to the player’s experience.

    The investigation, however, did not end there. When participants described their experiences directly, a rather different picture emerged. Questionnaire responses consistently indicated that sound influenced immersion, enjoyment and the overall quality of play. Players recognised differences that the physiological measurements had failed to capture. Far from undermining the original hypothesis, the contrasting results raised a much more interesting question. The problem may have lain not with the importance of sound, but with the methods used to measure its effects.

    Professor Nacke reflected on several possible explanations. Physiological signals fluctuate for many reasons, many of them unrelated to the specific design features being investigated. More importantly, the experiment averaged measurements across relatively long periods of gameplay. Memorable moments rarely unfold in that way. A sudden enemy encounter, an unexpected sound cue or the brief confirmation that an action has succeeded may last only a fraction of a second. Averaging responses across several minutes risks smoothing away precisely the moments that matter most.

    That observation carries implications extending well beyond this individual study. Human experience is rarely distributed evenly across time. Games are composed of countless moments requiring players to notice, decide and respond. Audio often contributes most powerfully at those precise instants, directing attention, confirming actions or warning of imminent danger. A research method designed to capture overall levels of physiological arousal may therefore overlook the highly localised effects that make sound so valuable during interaction.

    In many ways, this became one of the most revealing aspects of the lecture. Scientific research is often presented as a straightforward progression from hypothesis to confirmation. Professor Nacke instead demonstrated something much closer to the reality of research. Unexpected findings do not necessarily invalidate an idea. Sometimes they expose limitations in the way questions have been framed or measurements have been collected. Negative or ambiguous results become opportunities to design better experiments rather than reasons to abandon promising theories.

    By this point, the discussion had moved well beyond the simple question of whether sound matters. The evidence already suggested that players experience games differently when audio changes. Research was no longer asking whether sound mattered. It had begun asking how games should communicate with their players. That shift naturally pointed towards the future of game audio research, where the challenge is no longer proving that audio influences experience, but understanding which sounds matter most, which forms of feedback guide behaviour most effectively and how interactive systems can communicate with players more clearly, naturally and intelligently.

    By the end of the lecture, the original question had changed almost completely. It no longer seemed particularly interesting to ask whether sound matters in games. Few experienced players would seriously argue that it does not. A more revealing question had emerged instead. How should games communicate with their players? Once viewed through that lens, sound becomes much more than an aesthetic choice. It becomes one of the primary ways interactive systems explain themselves.

    Such a shift carries important consequences for the future of game design. Advances in graphics have often dominated discussions of technological progress, while audio has frequently been treated as a complementary layer added once the visual experience has been established. Professor Nacke’s work suggests that this sequence deserves to be reconsidered. If sound continually guides attention, confirms actions and shapes decision-making, then it should be regarded as part of the interaction itself rather than something applied afterwards to increase realism or atmosphere.

    Sound designers also occupy a rather different position within this way of thinking. Creating convincing effects and emotionally engaging soundtracks remains an essential part of the craft, yet interactive media asks for something more. Every cue becomes part of an ongoing dialogue between player and game. A well-designed sound does not merely create excitement or reinforce mood. It helps players understand where they are, what has changed and how they should respond next. Good game audio therefore succeeds not simply when it sounds impressive, but when it communicates clearly while remaining almost invisible.

    Lessons emerging from game audio extend far beyond entertainment. Interactive systems increasingly shape everyday life, from educational software and medical training to vehicle interfaces, industrial control systems and virtual reality. Each depends upon users making accurate decisions within changing environments. Many of those decisions rely upon information that can be communicated more quickly and more intuitively through sound than through visual displays alone. Games therefore provide an unusually rich environment in which to explore how people receive, interpret and act upon information under constantly changing conditions.

    Equally revealing was Professor Nacke’s willingness to embrace uncertainty. The physiological experiment did not produce the clear confirmation the researchers had hoped for, yet that outcome ultimately opened more interesting questions than it closed. Which sounds matter most? At what moments do they influence behaviour? How should researchers measure effects that may last only fractions of a second? Scientific progress rarely follows a straight line. Careful experiments often reveal that the next question is more valuable than the original answer.

    Looking back to the opening paradox makes that progression easier to appreciate. Players may continue to rank graphics above audio when asked which aspects of a game matter most. Yet the lecture suggests that such judgements overlook the extent to which sound quietly supports many of the qualities they value most. Confident interaction, satisfying feedback, effective learning and a strong sense of presence all depend upon communication between player and system. Much of that communication happens through sound, even when players scarcely notice it.

    Future interactive technologies will make these questions even more important. As games and other digital systems become increasingly adaptive, personalised and intelligent, designers will need to think less about individual sensory channels and more about the complete experience of interaction. Sound will remain one of the fastest, richest and most flexible ways of guiding attention without demanding it. Used thoughtfully, it can inform, reassure, warn, encourage and teach, often within fractions of a second.

    Professor Nacke’s most enduring contribution may be a simple change in perspective. Game audio is not fundamentally about making virtual worlds louder, more cinematic or more realistic. It is about making interaction intelligible. Every carefully designed cue, every subtle confirmation and every moment of auditory feedback helps players understand a world that exists only through continual exchange between person and system. Sound is not simply something games produce. It is one of the ways games reveal themselves to their players, allowing them to understand, navigate and ultimately master the worlds they inhabit.

  • How Can Sound Change What We Taste? Charles Spence on Crossmodal Perception, Multisensory Design, and the Future of Experience

    Charles Spence

    How much of flavour actually comes from the food itself?

    Most people would probably answer almost all of it. Sweetness belongs to sugar, bitterness belongs to coffee, freshness belongs to mint and carbonation belongs to sparkling water. Sound certainly accompanies these experiences, but it seems difficult to imagine that it could fundamentally change them. Whether a room is silent or filled with music, whether somebody eats alone or in a crowded restaurant, surely the food itself remains exactly the same.

    Everyday experience, however, quietly points in another direction. Coffee often tastes less satisfying on an aircraft than on the ground. Crisps seem fresher when they produce a louder crunch. Champagne feels more celebratory when its bubbles sparkle audibly in the glass, while the atmosphere of a restaurant can transform the enjoyment of a meal without a single ingredient changing. None of these observations seems especially surprising on its own. Taken together, however, they raise a rather uncomfortable question. If the food has not changed, what exactly has?

    That question formed the starting point for Professor Charles Spence’s online guest lecture for Edinburgh Napier University. As Head of the Crossmodal Research Laboratory at the University of Oxford, Spence has spent more than two decades investigating how the senses interact to construct experience. His research spans psychology, neuroscience, design and consumer behaviour, leading to collaborations with chefs, airlines, manufacturers, advertisers, perfumers and technology companies. Food featured prominently throughout the lecture, yet it soon became clear that gastronomy was simply one expression of a much broader scientific question.

    For much of modern science, the senses were treated as though they operated independently. Vision belonged to the eyes, hearing to the ears, taste to the tongue and smell to the nose. Perception appeared to be assembled almost like a jigsaw, with each sense contributing its own separate piece before the brain combined them into a complete picture. Spence’s work challenges that assumption. Information arriving through one sensory pathway immediately begins influencing the interpretation of information arriving through another. What people hear alters what they believe they taste. What they see changes what they expect to smell. The texture of a surface influences impressions of quality before conscious reasoning has even begun. Rather than operating as isolated systems, the senses appear to cooperate continuously, constructing experience through their interaction rather than through their independence.

    Sound therefore occupies a rather different role from the one most people imagine. Rather than serving simply as accompaniment, decoration or atmosphere added after an experience has already been designed, it becomes one of the materials through which perception itself is shaped. A carefully chosen sound can influence whether food seems fresher, sweeter, more bitter or more luxurious. It can establish expectations before the first mouthful, alter emotional responses during consumption and even affect the memories people later form of an experience. Sound does not simply accompany flavour. Under the right conditions, it helps create it.

    As the lecture unfolded, experimental psychology sat comfortably alongside fine dining, product packaging, aircraft cabins, advertising, perfume, digital interfaces and some of the world’s most celebrated restaurants. At first sight these subjects seemed to have little in common beyond an occasional reference to sound. Gradually, however, a consistent pattern emerged. Experiences that appear to belong almost entirely to one sense are often shaped by several others at the same time.

    Food was only the beginning. If hearing can influence taste, perhaps many experiences usually treated as purely visual, tactile or auditory are also products of continual interaction between the senses. The challenge for designers is therefore no longer simply to create attractive sounds, images or objects in isolation. It is to understand how they work together to shape perception as a whole. That broader question ultimately became the central theme of Spence’s lecture, pointing towards a future in which sound is understood not as an accessory to experience, but as one of the materials from which experience itself is constructed.

    If sound can influence flavour at all, the obvious question is how. At first sight the idea seems almost impossible. Taste depends upon chemical receptors inside the mouth, while hearing begins with vibrations entering the ears. One system detects molecules, the other detects pressure waves. They appear to have almost nothing in common. Yet the experiments Charles Spence presented suggest that the brain pays surprisingly little attention to these traditional boundaries. Instead of treating each sense as an isolated source of information, it continually searches for relationships between them.

    Every meal illustrates this process. Before food even reaches the mouth, its appearance has already created expectations about freshness, sweetness, richness or quality. Aroma begins shaping anticipation, while the weight of cutlery, the texture of a plate and the surrounding environment all contribute further information. Sound enters that process from the beginning. The clink of a glass, the crack of a crisp crust, the fizz of a carbonated drink and the background atmosphere of a restaurant all become additional clues from which the brain constructs a single interpretation. People do not consciously separate these sensations before combining them again. They simply perceive flavour.

    For many years, perception was often described as though the senses operated independently. Vision belonged to the eyes, hearing to the ears, taste to the tongue and smell to the nose, while the brain merely assembled their separate outputs into a complete picture. Increasingly, evidence points towards something much more dynamic. Information arriving through one sense immediately begins shaping the interpretation of information arriving through another. What people hear alters what they believe they taste. What they see changes what they expect to smell. Texture influences impressions of quality before conscious reasoning has even begun. Human perception emerges through continual interaction rather than through the addition of independent sensory streams.

    Spence explored these relationships through what he describes as crossmodal correspondences. Although the terminology sounds specialised, the underlying phenomenon is surprisingly familiar. Many people instinctively associate higher-pitched sounds with sweetness and lower pitches with bitterness. Other combinations of pitch, timbre, rhythm and texture consistently evoke impressions such as freshness, creaminess or sharpness. None of these relationships is consciously taught, yet they appear repeatedly when large groups of people are asked to match sounds with tastes.

    Consistency is what makes these findings especially significant. Individual preferences naturally vary, but the broader patterns remain remarkably stable. Participants who have never met one another frequently make similar associations, suggesting that these relationships are not simply matters of personal preference or cultural coincidence. Human perception appears to organise sensory information in surprisingly consistent ways. Designers therefore gain something unusually valuable: perceptual tendencies that can be anticipated rather than guessed.

    Crossmodal correspondences are sometimes confused with synaesthesia, despite important differences. People with synaesthesia may genuinely experience colours when hearing music or perceive letters as possessing particular tastes. Those experiences are real, but they are also highly individual. Crossmodal correspondences operate differently. They describe tendencies shared across many people rather than unique experiences belonging to particular individuals. That distinction allows them to move from psychological curiosity to practical design principle.

    Laboratory findings soon begin to acquire practical significance. Spence described collaborations in which composers and sound designers created musical soundscapes intended to reinforce particular taste qualities. Pitch, rhythm, timbre, consonance and articulation were carefully manipulated to suggest sweetness, bitterness, sourness or saltiness. Participants consistently matched particular soundscapes with particular tastes. More remarkably, under appropriate conditions those same soundscapes subtly altered the way the food itself was perceived. Music associated with sweetness could increase perceived sweetness without any change to the ingredients. Chemistry remained exactly the same, yet perception shifted in a predictable direction.

    Taste, in other words, emerges through interpretation rather than chemistry alone. Molecules reaching the tongue remain essential, but they represent only one source of information among many. Every sound surrounding a meal, from the crunch of food itself to the atmosphere of the room, contributes another piece of evidence that the brain may incorporate into its final judgement. Designers have often exploited these relationships intuitively for decades. Spence’s research provides a scientific explanation for why they work.

    Viewed from this perspective, familiar experiences begin to appear rather different. The satisfying crack of a crisp packet, the hiss of a freshly opened bottle or the sound of coffee being ground no longer seem like incidental by-products of physical events. They become active components of perception itself. Some establish expectations before tasting even begins. Others reinforce qualities already present or quietly direct attention towards particular sensations. Sound no longer sits outside flavour. It has become one of the ingredients from which flavour itself is assembled.

    Once the relationship between sound and flavour becomes scientifically plausible, an even more interesting question begins to emerge. What happens when designers start working with that knowledge? Crossmodal perception is no longer simply an explanation for a series of intriguing laboratory experiments. It becomes a different way of thinking about the creation of experiences. If perception is constructed through continual interaction between the senses, then every sound surrounding a product becomes part of the product. Designers are no longer shaping isolated objects or individual sensory channels. They are shaping the conditions under which people construct experience.

    That shift in perspective explains why Charles Spence’s research extends so far beyond psychology. His collaborations have involved chefs, advertisers, manufacturers, retailers, technology companies and designers working across remarkably different industries. At first sight those partnerships appear unrelated. Yet each asks essentially the same question. If sound changes the way people perceive quality, freshness, luxury or value, how should products and experiences be designed differently?

    Many organisations have traditionally approached multisensory design by attempting to stimulate as many senses as possible. Spence suggested that this is only part of the challenge. More sensory information does not necessarily create a better experience. Success depends upon coherence rather than quantity. Vision, sound, touch, smell and taste need to reinforce one another, guiding perception towards a shared interpretation. A beautifully designed sound can strengthen what people already expect to encounter. An inconsistent one can quietly undermine the entire experience.

    Small design decisions therefore begin to acquire unexpected significance. Opening a packet of crisps, hearing the hiss of a carbonated drink or listening to coffee beans being ground may seem like incidental moments within a much larger experience. Yet those sounds establish expectations before tasting even begins. They encourage the brain to anticipate freshness, quality or intensity long before chemistry has an opportunity to contribute. The product remains physically unchanged. What changes is the perceptual framework through which the product is interpreted.

    Few environments demonstrate these relationships more clearly than restaurants. Every aspect of a meal contributes information beyond the food on the plate. Lighting, tableware, acoustics, conversation and music all participate in shaping expectations and emotional responses. Fine dining therefore becomes an exercise in multisensory design rather than culinary technique alone. Preparing exceptional food remains essential, yet the overall experience emerges from the interaction of many carefully orchestrated elements.

    One of the lecture’s most celebrated examples came from Heston Blumenthal’s Sound of the Sea. Diners listened to recordings of waves, seabirds and the sounds of a coastal landscape while eating a seafood course. Initially the idea appeared almost whimsical. Why should listening to the sea alter the taste of food served indoors? Yet diners consistently described the dish as fresher, more vividly maritime and more immersive when accompanied by the soundscape. Even members of Spence’s own research group admitted that the strength of the effect had surprised them. What initially appeared to be a theatrical flourish turned out to reveal something far more fundamental about the way perception operates.

    Experiments of this kind naturally led towards increasingly sophisticated forms of experience design. Spence described cocktail events in which each drink was paired with its own carefully composed soundscape. Participants were invited to compare different combinations, discovering how subtle changes in the auditory environment altered the character of the same drink. Attention gradually shifted away from asking whether one cocktail tasted better than another. Instead, the question became how the interaction between sound and flavour could produce the most satisfying overall experience. Perception itself had become the object of design.

    Once viewed from this perspective, the implications become difficult to contain within food and drink alone. Mobile devices, consumer products, retail spaces, packaging and digital interfaces all communicate through sound, whether intentionally or accidentally. Notification tones, confirmation signals, mechanical clicks and interface feedback continually influence users’ impressions of quality, reliability and identity. Those sounds are not decorative additions arriving after the creative process has finished. They help determine how the product itself is understood.

    Perhaps the most important lesson from this part of the lecture is that food was never really the subject. Food simply makes multisensory perception unusually easy to observe. Once the underlying principles become visible, they begin appearing almost everywhere. Products, services, environments and digital technologies all rely upon the same interactions between the senses. Sound therefore ceases to be something added to an experience. It becomes one of the materials from which perception itself is constructed.

    By the end of the lecture, it became increasingly difficult to think about sound in quite the same way as before. Traditional approaches to sound design often begin by asking what something should sound like. Charles Spence’s work quietly suggests a different question. What should people perceive? Those two objectives frequently overlap, but they are not identical. A sound can be technically accurate while contributing little to the intended experience, or it can depart from physical realism yet guide perception in ways that feel entirely convincing. The designer’s task therefore extends beyond producing sounds. It becomes one of shaping interpretation.

    That shift carries important implications for the future of design. Emerging technologies make these ideas increasingly relevant. Artificial intelligence can already personalise recommendations, anticipate preferences and generate new forms of interaction in real time. Yet many of these developments continue to treat the senses as largely separate channels through which information is delivered. Spence’s research points towards a different possibility. Systems might instead learn how combinations of sound, vision, touch and other sensory cues influence perception as a whole, adapting experiences rather than simply adapting individual outputs.

    Such ideas extend naturally into interaction design, healthcare, education, transport and entertainment. A navigation system might reduce stress by carefully coordinating spoken instructions, interface sounds and visual feedback. Assistive technologies could combine auditory and tactile information to improve confidence and accessibility. Retail environments may shape perceptions of quality without relying solely upon visual presentation, while museums, exhibitions and virtual environments can construct richer experiences through carefully orchestrated sensory relationships. None of these applications depends upon one extraordinary technological breakthrough. They emerge from a deeper understanding of how people already perceive the world.

    Sound designers occupy a particularly interesting position within this changing landscape. Traditionally, sound has often entered the creative process after many other design decisions have already been made. Music, ambience and effects enrich an experience that largely exists in visual or physical form. Multisensory research challenges that sequence. If sound actively participates in constructing perception, it deserves consideration from the earliest stages of design rather than being treated as a finishing touch. Decisions about audio become decisions about cognition, emotion and behaviour.

    This perspective also encourages greater humility. Human perception remains remarkably complex, and no designer can predict every response with complete certainty. Cultural experience, personal memory, expectation and context all continue to influence how people interpret the same sensory information. Spence repeatedly acknowledged that multisensory design is not a collection of universal formulas guaranteeing identical outcomes for every individual. Instead, it offers evidence-based principles that increase the likelihood of particular perceptual responses while recognising that people remain active participants in constructing their own experiences.

    Perhaps that is why the lecture remained so compelling. It never suggested that science could replace creativity or reduce design to a set of predictable rules. On the contrary, scientific understanding expanded creative possibility rather than limiting it. Once designers understand how the senses cooperate, they gain entirely new materials with which to work. Sound becomes capable of shaping flavour, texture, atmosphere, expectation and memory alongside its more familiar roles in communication and emotion. Creativity is not constrained by such knowledge. It is given a richer foundation upon which to build.

    Returning to the opening question reveals how much has changed. How much of flavour actually comes from the food itself? Chemistry remains indispensable, but chemistry alone is no longer a sufficient answer. Flavour emerges through continual interaction between taste, smell, vision, touch, sound and expectation, each contributing to a perceptual whole that cannot easily be reduced to its individual parts. Food becomes one component of a broader multisensory experience rather than its sole determinant.

    That conclusion reaches well beyond gastronomy. Every designed experience, whether a film, game, product, concert hall, mobile application or public space, is ultimately encountered through the cooperation of the senses. Designers therefore shape more than objects, interfaces or soundtracks. They shape the perceptual conditions through which people understand the world around them.

    Perhaps the most enduring contribution of Charles Spence’s work is not the demonstration that sound can make food taste sweeter or fresher, remarkable though those findings remain. It is the reminder that perception itself is creative. The brain does not passively record reality. It continually interprets, predicts and combines information arriving from many different sources, constructing an experience that feels immediate, coherent and effortless. Sound is not merely something that accompanies that process. It is one of the materials from which that process is built.

  • How Do You Preserve the Sound of a Place? Damian Murphy on OpenAir, Acoustic Heritage, and Reconstructing Lost Spaces

    Damian Murphy

    How do you preserve the sound of a place?

    A building can survive through photographs, architectural drawings, maps and written descriptions. Its dimensions can be measured, materials catalogued and appearance reconstructed long after the original structure has disappeared. Yet places are not experienced through vision alone. A cathedral changes the sound of a choir, a tiled chamber changes the sound of a voice, snow alters the acoustic behaviour of a forest, and the hard surfaces of a mausoleum can allow sound to continue long after its source has stopped. Architecture surrounds every action with reflections, resonances and reverberation, but this part of a place can disappear without leaving anything visible behind.

    During his online guest lecture for Edinburgh Napier University, Professor Damian Murphy of the University of York explored almost two decades of work investigating how the acoustics of places can be measured, preserved, reconstructed and experienced. Much of this work centres upon OpenAir, the Open Acoustic Impulse Response Library, which contains acoustic measurements gathered from buildings, landscapes and other environments. Its contents range from cathedrals, churches and theatres to industrial buildings, caves, forests and vehicles, connecting acoustic science with music production, spatial audio, games, archaeology, heritage and historical research. Murphy moved between these different places and applications through a question that became larger as the examples accumulated. What can the sound of a place tell us that its image cannot?

    Murphy began with a ruin. The Temple of Decision stands on a hill overlooking the Falkland Estate in Fife, where artists David Chapman and Louise K. Wilson had been commissioned to explore the landscape through sound. Archive material could offer clues about the temple’s former appearance, while historical research could provide fragments of information about its use, but the surviving structure could no longer reveal how the intact building had sounded. What would it have been like to speak inside the room? How might voices have behaved around a table? How would conversation, movement or a fire have interacted with its surfaces? The artists posed a question that provided a starting point for Murphy’s lecture: in the absence of clear echoes, how can we know a place?

    Answering that question first requires an understanding of what an acoustic environment contributes to anything heard within it. Imagine a short, sharp sound produced inside a room. A listener initially receives the direct sound travelling along the shortest path from source to receiver. Early reflections arrive shortly afterwards from nearby surfaces, followed by increasingly complex patterns as energy travels through the room, interacting repeatedly with walls, floor, ceiling and objects before gradually decaying. Together, these components form a room impulse response for a particular relationship between a source and receiver. Direct sound carries information about the source and its distance, while early reflections contribute to perceptions of geometry and position. Later reverberation communicates qualities associated with volume, materials and enclosure. Change the architecture and the response changes. Move the source or listener and it changes again. An impulse response is therefore not a complete acoustic identity for a building, but a record of how sound travelled between particular positions under particular conditions.

    Once captured, that relationship can be used for more than numerical analysis. Through convolution, a recording made without significant room acoustics can be combined with an impulse response measured elsewhere. Murphy demonstrated the process using a four-part vocal ensemble recorded in an anechoic chamber. The singers had never performed in York Minster, yet convolution with a measured response allowed their dry voices to acquire characteristics of the cathedral. York Minster has a reverberation time of approximately eight seconds through part of the mid-frequency range, compared with around half a second for a typical living room. Voices behave very differently in each environment. Notes overlap, transitions blur and the building continues sounding after the performers have stopped producing sound. The acoustic is not simply decoration placed around a performance. It changes the temporal relationships through which that performance is heard.

    Auralisation, however, introduces a distinction between recreating acoustic conditions and recreating experience. Singers performing in an anechoic chamber do not behave as they would inside a highly reverberant cathedral. Performers hear themselves and adapt. Tempo, articulation, phrasing, dynamics and pauses can change in response to sound returning from the room, while musicians continually adjust to one another through the acoustic environment they share. Convolution can reproduce the effect of a measured response upon a recording, but it cannot retrospectively create the performance that might have developed inside that space. Murphy acknowledged this limitation directly when discussing the York Minster example. The anechoic performance was not the performance the singers would have given in the cathedral, and even the spacing of phrases in the demonstration had been altered to allow the reverberation to emerge more clearly.

    The distinction matters beyond the simulation of reverberation. A room impulse response can describe how energy travels between defined positions, but people are not passive sound sources or microphones. They move, listen selectively, change their behaviour and respond to what they hear. Preserving a response gives researchers evidence about the acoustic conditions of a place. What people did in response to those conditions remains a different question.

    OpenAir developed from an ambition to preserve such evidence and make it available for others to explore. Murphy traced one important influence to Angelo Farina’s work on recording concert halls for posterity. Improvements in measurement techniques and the emergence of practical convolution reverberation created an opportunity to document significant spaces not merely through reverberation times and other summary values, but through impulse responses that could be analysed, reproduced and used creatively. OpenAir extended this principle into a growing archive, with a measurement system designed to collect spatially rich data that could remain useful beyond the immediate research question.

    Early measurement sessions used a Genelec S30D loudspeaker to excite the space while microphones captured its response. A computer-controlled turntable allowed measurements at regular angular intervals, and an ambisonic Soundfield microphone was combined with a Neumann KM100 cardioid microphone to provide spatial information alongside material suitable for different forms of analysis and production. Measurements could be repeated across several source and receiver positions, preserving a set of relationships rather than presenting each building through one supposedly definitive response. Ambisonics was particularly valuable for an archive whose future applications could not be predicted. A first-order ambisonic recording represents a three-dimensional sound field through an omnidirectional component and three directional components, separating the captured information from one fixed loudspeaker arrangement. Material can later be decoded for different reproduction systems or manipulated in ways that may not have been anticipated when the recording was made.

    Flexibility matters when access to a significant site may last only a few hours. Researchers need to gather material rich enough to support questions that have not yet been formulated and technologies that may change long after a measurement session has ended. During the discussion after the lecture, Murphy described more recent work at St Paul’s Cathedral, undertaken with a composer who wanted impulse responses from the building. Three researchers had only three hours to move equipment through the enormous space and capture responses from locations including the nave, a stairwell and the Whispering Gallery. Practical decisions about where to measure become part of preservation itself. As Murphy observed, there is no single sound of a large building. Different positions offer different acoustic experiences, and any archive necessarily records selected relationships within a much larger field of possibilities.

    As OpenAir expanded, its growing range of places made the idea of acoustic preservation less straightforward. York Minster was an obvious candidate, since its long reverberation is closely connected with experiences of worship, tourism and musical performance. Other sites raised different questions about what deserves to be preserved and why. When the former Terry’s chocolate factory in York closed, Murphy and his colleagues gained access before redevelopment and measured spaces including a warehouse and the former typists’ room, a striking interior dominated by glass and wood. The activities for which these spaces had been designed had already disappeared. An empty typists’ room could still be photographed, but its appearance prompted another question: what might it have sounded like when filled with the overlapping mechanical activity of typewriters?

    A subterranean reactor hall beneath the Royal Institute of Technology in Stockholm preserved another relationship between architecture and former activity, while measurements in historic churches allowed acoustic theories to be tested rather than merely repeated. At St Andrew’s Church in Lyddington, the team examined jars embedded within the walls, architectural features sometimes interpreted through theories of resonant vessels extending back to the Roman architect Vitruvius. Measurement provided little evidence that the jars were making a substantial contribution to the acoustic character of the church. Their form did not correspond closely with the behaviour expected of effective Helmholtz resonators. Acoustic research could challenge explanations attached to historic architecture as well as document spaces admired for their sound.

    York Theatre Royal shifted attention from buildings as fixed objects towards places in changing states. Murphy’s team measured the auditorium before refurbishment and returned afterwards to document its altered acoustic. They also captured measurements with an audience present during a pantomime, recognising that an occupied theatre does not behave acoustically like the same room when empty. Seats, clothing and bodies absorb and scatter sound, making occupancy part of the acoustic system rather than simply a group of listeners placed within it. Materials age, spaces are repurposed and environmental conditions change. Preserving an acoustic environment may therefore involve documenting several states of the same place rather than searching for one definitive response.

    Outdoor and semi-outdoor locations created different practical problems, and the original measurement system could not simply be carried everywhere. On the Falkland Estate, the Bottle Dungeon could be reached through a trapdoor, but access was sufficiently awkward that the usual equipment was impractical. A balloon was attached to one stick, a pin to another and a microphone lowered into the space. Bursting the balloon remotely provided the excitation needed to capture a response. The improvised arrangement was far removed from the computer-controlled turntable used elsewhere, yet it addressed the same underlying need: introduce a suitable sound into an inaccessible environment and record how the space transforms it.

    Landscapes demanded further adaptation. Equipment had to become portable and independent of mains electricity as researchers travelled into the Yorkshire Dales to measure caves and gorges. Work in Finland examined the same forest under different seasonal conditions. Researchers used GPS alongside ribbons tied around trees to return to the same positions after deep snow had transformed the landscape. Geographically, it remained the same forest. Acoustically, it had changed. Snow altered the interaction between sound, ground and surrounding environment, demonstrating that acoustic character can change while location remains constant.

    A collaboration with Codemasters carried that thinking into interactive media. Looking at an archive rich in churches and historic interiors, the developer asked a practical question: what about the environments needed for games? The collaboration encouraged further work on landscapes and led to experiments for GRID Autosport involving vehicle interiors, where the acoustic problem was unusually complex. Codemasters wanted to represent a car gradually falling apart during a race, so the team needed measurements capable of describing changing states, including doors opening or disappearing and the boot being open. The experience of being inside a racing car also comes from more than airborne sound. Engine vibration travels mechanically through the structure and contributes to what an occupant hears and feels.

    Conventional room measurement could not fully represent that relationship, so Murphy and his colleagues experimented with using the engine itself as part of the measurement process. Revving the car caused the structure to vibrate as it would during use, after which signal-processing methods were applied to separate the excitation from the resulting cabin response and derive an approximation of the impulse response. The approach sought to preserve something more specific than the reverberation of a small enclosure. It attempted to capture the interaction between a vibrating machine, its structure, the enclosed air and the listener inside it.

    Games also demonstrated how preservation can become creative infrastructure. An impulse response gathered for research may later help construct a virtual environment, become part of a music-production tool or support a question that had not existed when the measurement was made. Murphy described OpenAir material finding its way into software used by musicians and audio practitioners, allowing measurements collected years earlier to acquire new purposes. Distribution under a Creative Commons licence reflected this wider ambition. Researchers can analyse the acoustic behaviour of a building, composers can use the same response creatively, sound designers can place fictional events inside measured environments and developers can incorporate selected material into new tools.

    OpenAir originally allowed members of the wider community to upload their own measurements. As contributions accumulated, variations in recording quality became difficult to ignore. The team eventually reviewed the existing material, retained the strongest contributions and moved towards a more curated model in which new contributors contact the team directly. Open access expands what an archive can become, but reuse also depends upon confidence in how the material was produced.

    These measurements deal with places that still exist, even when they are changing. The Temple of Decision presents a different problem. Its original interior has already gone. Once a room has disappeared, there is nothing left to measure. Its former acoustic behaviour has to be approached indirectly through surviving evidence and modelling.

    Using information about a lost structure, researchers can construct a three-dimensional geometric representation and simulate the propagation of sound within it. Virtual rays travel through the model, reflecting between surfaces to generate impulse responses for selected source and receiver positions. Those responses can then be analysed or used to process voices and other recordings, allowing listeners to hear an interpretation of how sound might have behaved inside architecture that no longer survives. Such a result differs fundamentally from measuring an existing building. Geometry may be uncertain, material properties need to be estimated and every modelling method introduces limitations. Historical auralisation produces an evidence-based acoustic proposition rather than a recording recovered from the past.

    Work on St Mary’s Abbey in York made both the possibilities and limitations of this approach audible. The former church survives as a ruin, while archaeological and architectural evidence allowed Murphy’s team to construct a three-dimensional representation suitable for acoustic modelling. Simulated impulse responses could then be compared with measurements from York Minster, a surviving building with some comparable characteristics. Estimated reverberation times occupied a similar range, but the reconstructed St Mary’s sounded noticeably brighter. The difference did not necessarily reveal a historical distinction between the buildings. Murphy explained that the ray-tracing model used for St Mary’s was less effective at reproducing low-frequency behaviour than the physical measurement system used in York Minster. Part of what listeners heard therefore belonged to the method of reconstruction itself.

    A model may sound convincing while still containing audible consequences of the technique used to create it. Plausibility has to emerge from evidence, comparison and methodological transparency rather than from the apparent realism of the result alone. Once those boundaries are understood, a model can make relationships perceptible in ways that drawings and numerical data cannot. During a public performance among the ruins of St Mary’s Abbey, a live choir was captured and processed through impulse responses derived from the reconstructed church, then projected to an audience gathered at the site. Present-day voices sounded among the physical remains while the model returned an interpretation of the missing acoustic architecture. Research data became part of an experience connecting a surviving place with a vanished interior.

    Reconstructing an abbey or temple can help audiences imagine how a lost building might have shaped music and speech. Murphy’s more recent work moved towards a question with wider historical consequences. If architecture changes what people can hear, could reconstruction help investigate who had access to speech in the past?

    Working with historians and art historians, Murphy’s team investigated spaces associated with the historic House of Commons within the former Palace of Westminster. Among the most revealing parts of that history was the experience of women who listened to parliamentary debate from a roof space above the chamber. Known as the Ventilator, this space allowed women excluded from formal political participation to gather above the House of Commons and listen through the architectural structure separating them from the debate below. Historical evidence could establish that they were there. Acoustic reconstruction allowed another question to be asked: what could they actually understand?

    Answering it required more than recreating the debating chamber as an isolated room. Researchers had to consider the chamber, roof void, Ventilator and routes through which speech travelled. The women listening above did not have a direct line of sight to the speaker, making their experience a problem of acoustic transmission through a complex architectural arrangement rather than ordinary listening within a single enclosure. Murphy connected this project with broader questions of directionality, speech transmission and listening position, while acknowledging that objective measures cannot reproduce every aspect of human attention or historical experience.

    No surviving recording can reveal exactly what those listeners heard. The team therefore combined historical reconstruction with comparative measurement, examining surviving spaces connected with parliamentary history or comparable in geometry, scale, period or use. Measurements from rooms at the University of Oxford, York Guildhall and the present House of Commons chamber provided contexts against which aspects of the model could be considered. None could prove how the lost chamber sounded, but together they allowed reverberation and speech intelligibility to be examined across different positions and occupancy conditions. A question about architectural acoustics had become inseparable from a question about political access.

    Hearing is a form of access. Architecture, distance, reverberation, occupancy and barriers influence whether speech remains intelligible, while attention, familiarity and expectations affect what can be understood from imperfect information. A person may be physically close to political debate while remaining acoustically separated from it. Reconstructing the conditions of listening can therefore contribute to historical questions about participation and exclusion that visual records alone cannot answer.

    The Temple of Decision now appears less like an isolated case and more like the beginning of a much larger enquiry. In the absence of clear echoes, how can we know a place? We can measure what survives, compare different conditions, preserve spaces before they change and build models from evidence when the original architecture has disappeared. We can listen to those models while remaining clear about what they can and cannot establish. Most of all, we can ask questions that become difficult to formulate when architecture is treated only as something seen.

    A photograph can preserve the appearance of a parliamentary chamber from one position. An architectural plan can show where walls, doors, galleries and roof spaces were located. Written testimony can tell us that people gathered somewhere to listen. Acoustic research adds another layer by asking how sound travelled between those positions, how reverberation affected speech and whether architecture enabled or obstructed understanding. The same thinking can ask how a ruined abbey shaped musical performance, how a theatre changed during refurbishment or how winter transformed the acoustic behaviour of a forest.

    Preserving the sound of a place is not simply an attempt to save an attractive reverberation before it disappears. Places participate in human activity. They change how people speak, perform and listen. Their surfaces and geometry influence whether voices remain intimate or become collective, whether musical phrases overlap or remain distinct, and whether somebody standing beyond a barrier can understand words spoken elsewhere. Acoustic conditions can shape behaviour, access and participation without leaving a visible trace.

    The Temple of Decision can still be visited. St Mary’s Abbey remains visible as a ruin. The old House of Commons chamber has disappeared, while the former typists’ room at Terry’s chocolate factory no longer performs its original function. A forest changes when snow arrives and changes again when it melts. Even a building that survives intact contains many acoustic relationships, only some of which can be measured during the limited hours when researchers have access.

    Sound is especially vulnerable to disappearance. Once a room changes, an audience leaves or a building is lost, its former acoustic behaviour cannot simply be photographed. Murphy’s lecture showed that it is not entirely beyond preservation. What remains may be a measurement, a model, a comparison or a carefully documented uncertainty, each offering a different way of understanding a place as more than a visual container for history.

    In the absence of clear echoes, we may never know a place completely. We can, however, preserve evidence of how sound moved through it, reconstruct plausible relationships when the original has disappeared and ask what those acoustics meant for the people who performed, spoke and listened there. An impulse response may last only a few seconds, yet within it can remain an acoustic trace of a cathedral, a factory, a theatre, a cave, a forest under snow or a room about to change forever. When the room itself has already disappeared, a model can return a possibility rather than a certainty: a voice reflecting from lost walls, a choir inhabiting a ruined abbey or political speech travelling towards listeners hidden above a chamber from which they were excluded.

    Preserving the sound of a place means preserving another way of understanding what happened there. Walls determine more than what people can see. They shape what can be heard, how clearly it can be understood and who is able to listen.

  • How Much Sound Does a Game Really Need? Gaetan Troutet on Casual Games, Creative Restraint, and Designing for the Real World

    Gaetan Troutet

    How much sound does a game really need?

    Most players never notice the sounds that have been deliberately left out of a game. During his online guest lecture for Edinburgh Napier University, Gaetan Troutet suggested that this is often the hallmark of successful sound design. Creating an effective soundtrack is rarely about filling every moment with audio. It is about deciding what genuinely deserves to be heard. Drawing upon his work developing casual games for Global Eagle Entertainment, he demonstrated how technical limitations, player behaviour and careful editorial judgement shape almost every creative decision. A single principle underpinned the discussion. Successful sound design depends as much upon restraint as invention.

    The environment in which Troutet’s games are played makes these decisions particularly demanding. Unlike many commercial titles developed for dedicated gaming hardware, his work must function across a diverse collection of in-flight entertainment systems installed on aircraft across the world. Some platforms provide comparatively modern hardware with generous storage and processing resources. Others continue to rely upon considerably older systems whose limited memory and bandwidth require soundtracks to be simplified before they can be deployed. The same game may therefore exist in several different technical versions, each shaped by the capabilities of the hardware on which it will eventually run. Even then, the hardware represents only part of the challenge. Every passenger experiences the soundtrack differently. Some use the headphones supplied by the airline, others connect their own, while many later encounter the same games on mobile devices with entirely different loudspeakers. Unlike a cinema or recording studio, there is no single reference listening environment. Troutet suggested that professional sound designers should accept this uncertainty rather than attempting to eliminate it. The objective is not to produce a soundtrack that sounds perfect under ideal conditions. It is to create one that continues to communicate effectively wherever it is heard.

    Although the lecture centred upon casual games, the questions Troutet raised apply to sound design far more generally. Every project exists within practical constraints, whether they involve memory budgets, processing power, production schedules or playback systems. Rather than viewing these restrictions as obstacles to creativity, Troutet argued that they often encourage clearer thinking. Once every sound occupies valuable storage, competes for the listener’s attention and requires implementation within a functioning game, designers become far more selective about what truly matters. Working as the sole audio practitioner within his development team reinforces that perspective. Troutet moves continually between creating sound effects, composing music, recording dialogue, implementing assets and collaborating with programmers and designers. Rather than treating these activities as separate disciplines, he presented them as interconnected parts of a single design process. Creative decisions influence implementation, technical limitations shape artistic choices and production realities affect every stage of development. Sound design therefore becomes inseparable from the wider process of building the game itself.

    One of the most thought-provoking moments in the lecture centred upon what appears to be a deceptively simple question. When a player performs an action, should that action always produce a sound? Many beginning designers instinctively answer yes. Buttons receive clicks. Menus receive confirmation tones. Every movement, selection, reward and transition appears to justify another layer of feedback. Troutet challenged this assumption directly. Rather than asking which sounds could be added, he encouraged students to ask which sounds genuinely improved the experience. Every additional sound competes for the listener’s attention. Every new cue alters the perceived importance of those surrounding it. Audio that initially appears informative can rapidly become repetitive, distracting or simply exhausting when heard hundreds of times during repeated play. Casual games make this question particularly important. Players often return to them repeatedly in relatively short sessions. Sounds that seem satisfying during the first few minutes may become irritating after dozens of repetitions. Troutet therefore described restraint as an active design decision rather than the absence of creativity. Silence is not an empty space waiting to be filled. It forms part of the overall balance of the soundtrack. Choosing not to add a sound may ultimately improve clarity far more than creating another effect.

    These same principles become particularly apparent in interface design, where audio functions less as decoration than as communication. Troutet encouraged students to think of interface sounds as messages directed towards the player rather than ornamental additions to menus and buttons. A confirmation tone, warning signal or navigation sound should communicate its purpose immediately, allowing players to understand what has happened without continually consulting the screen. One particularly memorable suggestion involved imagining the interface without any graphics at all. If a player were blindfolded and heard only the sounds, could they still distinguish success from failure, confirmation from cancellation, or navigation from selection? If the answer is yes, then the sounds are performing a genuine communicative role. If not, making them louder or more elaborate is unlikely to solve the underlying problem. Rather than treating interface sounds as decorative clicks or beeps, Troutet encouraged students to think of them almost as a spoken language. Every sound should communicate intention. Players should recognise whether an action has succeeded, failed or requires further input without consciously analysing what they have heard. Well-designed interface audio reduces cognitive effort. The player understands first and reflects afterwards. In this sense, interface sounds become part of the conversation between the game and the player rather than simply another layer of feedback.

    The same philosophy shaped Troutet’s approach to creating collections of related sounds. Rather than treating every effect as an independent recording selected from unrelated libraries, he described building what he called families of sounds. Interface elements, gameplay feedback and recurring actions share common characteristics, creating a recognisable sonic vocabulary throughout the game. Individual sounds may differ substantially in pitch, duration or function, though they continue to feel as though they belong together. Players may never consciously analyse these relationships, yet they often perceive the overall soundtrack as more coherent and easier to understand. Creating these relationships frequently meant recording original material rather than relying exclusively upon commercial sound libraries. Library recordings remain valuable resources, though bespoke recordings provide greater flexibility when developing a consistent sonic identity. Variations can be created from common source material, preserving subtle similarities that would be difficult to achieve using unrelated recordings gathered from multiple collections. The objective is not originality for its own sake. It is to ensure that every sound contributes towards a coherent listening experience rather than drawing attention to itself as an isolated event.

    Troutet consistently returned to the relationship between player experience and design judgement. Recording equipment, software and implementation techniques remained important, though they were never presented as ends in themselves. Every technical decision ultimately served the same objective: helping players understand, navigate and enjoy the game. Sound design therefore became an exercise in editorial judgement rather than accumulation. The important question was no longer how another sound might be added, but whether that moment genuinely deserved sound at all. Once that decision becomes the starting point, implementation, iteration and refinement begin to look rather different, forming the focus of the remainder of the lecture.

    Implementation forms the natural continuation of Troutet’s argument. Once the decision has been made that a sound genuinely deserves to exist, another set of questions immediately follows. When should it play? Under what conditions should it remain silent? How should it respond when players behave in unexpected ways? Troutet encouraged students to recognise that creating an individual sound is only one stage of the design process. A carefully recorded asset can still fail if it appears at the wrong moment, masks more important information or becomes repetitive through excessive triggering. Implementation therefore becomes an extension of sound design rather than a separate technical activity. Decisions about timing, variation and behaviour shape the player’s experience just as profoundly as the recordings themselves. Very few sounds remain unchanged after their first implementation. Once assets begin interacting with graphics, gameplay and player behaviour, weaknesses quickly become apparent. Sounds that worked well in isolation may feel intrusive within the finished game. Others disappear beneath music or gameplay effects, while some simply occur too frequently. Rather than treating these discoveries as failures, Troutet presented them as an expected part of development. Every implementation reveals more about how players actually experience the game, allowing successive revisions to refine the soundtrack until it supports interaction naturally.

    This willingness to revise also requires a particular creative mindset. Troutet observed that sound designers often invest considerable effort in creating individual recordings, making it tempting to defend them once they have been completed. Professional practice frequently demands the opposite approach. If a sound distracts players, interrupts the pacing of the game or simply fails to communicate effectively, attachment to the recording itself becomes irrelevant. During the lecture he summarised this philosophy with a familiar expression from creative practice: kill your babies. The phrase may sound severe, though the principle behind it is straightforward. The success of the overall experience matters more than preserving individual ideas. Removing or replacing a favourite sound is sometimes the decision that allows the remainder of the soundtrack to function more effectively. The willingness to edit critically therefore becomes every bit as important as the ability to create new material.

    The same philosophy extends beyond individual recordings into collaboration with the wider development team. Troutet repeatedly emphasised that sound design does not develop independently from programming, art or game design. Audio practitioners inherit decisions made elsewhere while simultaneously influencing the work of others. Effective collaboration therefore depends upon communicating design decisions in terms of the player’s experience rather than purely technical language. Requests for additional implementation features, changes to interface behaviour or modifications to gameplay become far easier to justify when they are framed around what players will understand, notice or enjoy. Communication, in this sense, becomes another aspect of sound design rather than an administrative task surrounding it. Professional organisation supports that collaboration in equally practical ways. Clear file names, consistent project structures and carefully maintained asset libraries rarely receive the same attention as recording or mixing, yet they influence every subsequent stage of production. Projects evolve over months or years, assets require continual revision and other members of the team must be able to locate the correct material quickly. Well organised sessions reduce confusion, simplify implementation and ultimately create more opportunities for genuinely creative work.

    Troutet also cautioned against becoming overly attached to particular software, plug-ins or recording equipment. Digital audio workstations continue to evolve, new tools appear regularly and production techniques inevitably change across a career. These developments undoubtedly influence professional practice, though they remain only means of achieving a larger objective. The more important questions concern what the player should hear, what information deserves emphasis and how audio contributes to the overall experience of the game. The same perspective shaped his comments on sources of inspiration. Commercial sound libraries, films and existing games all provide valuable references, though they should never replace careful design thinking. A distinctive soundtrack emerges through the relationships between sounds, the pacing of interaction and a clear understanding of the audience rather than through the novelty of any individual recording. Troutet consistently returned to the idea that sound design is fundamentally a process of making informed decisions rather than collecting techniques.

    Troutet repeatedly argued that sound should guide interaction rather than compete with it. Audio may reward success, reinforce important actions or draw attention towards changing events, though it should rarely distract players from the activity itself. This philosophy connects directly to the earlier discussions of restraint, interface communication and coherent families of sounds. Every element of the soundtrack exists to support understanding. Once a sound begins attracting attention to itself rather than to the player’s experience, its purpose deserves to be questioned. The measure of successful sound design is therefore not how much audio has been added to a game, but whether every element continues to justify its presence through the experience it creates for the player.

    The lecture concluded by returning, implicitly, to the same deceptively simple question that had shaped the discussion from the beginning. How much sound does a game really need? Troutet offered no universal formula. Different genres, audiences and platforms inevitably require different solutions. Instead, he encouraged students to replace assumptions with judgement. Does this sound communicate something important? Does it improve the player’s understanding? Does it strengthen the overall experience? If the answer is no, then adding more audio is unlikely to solve the problem. Careful omission often represents a stronger design decision than continual addition. Across examples ranging from airline entertainment systems to interface design, implementation and professional collaboration, Troutet consistently presented sound design as an exercise in thoughtful selection. The defining characteristic is judgement. Choosing which sounds deserve to exist, how they relate to one another and when they should remain silent requires an understanding of perception, interaction and communication that extends far beyond recording individual effects. Successful sound design is therefore measured not by the quantity of sounds within a project, but by how effectively those sounds help players understand, navigate and enjoy the worlds they inhabit.

  • How Do You Design Great Sound for Terrible Speakers? Tracy Bush on Creative Constraints, Game Audio, and Designing for the Real World

    Tracy Bush

    How do you design great sound for terrible speakers?

    Modern games present players with remarkably convincing sonic worlds. Dialogue responds naturally to changing situations, environments feel alive with movement and atmosphere, interfaces communicate information almost instinctively, and music adapts to the pace of play. Looking at contemporary productions, it is easy to imagine that these achievements are primarily the result of increasingly powerful technology. During his online guest lecture for Edinburgh Napier University, Tracy Bush suggested something rather different. Drawing upon a career that has included Blizzard Entertainment, Sony Online Entertainment, NCSoft and Sphero, he described how some of the most effective sound design emerges when technology imposes severe limitations. Small memories, limited processors, unpredictable playback systems and tiny loudspeakers do not simply restrict creativity. They force designers to think more carefully about what listeners genuinely need to hear.

    Bush’s own career reflected the rapid evolution of the games industry itself. Music had always formed an important part of his life, though his professional background began in information technology rather than audio. While working during the day, he spent evenings performing as a pianist in bars around San Francisco. After relocating to southern California, he joined Blizzard Entertainment in an IT role. His musical interests gradually became known throughout the company, leading colleagues to involve him in audio work whenever opportunities arose. Rather than following a carefully planned route into game sound, his career developed through a willingness to solve unfamiliar problems wherever they appeared. Looking back, Bush suggested that many people entered the industry in much the same way. Studios were small, responsibilities overlapped, and individuals frequently discovered new specialisms simply by becoming the person willing to tackle the next challenge.

    The games industry of the late 1990s differed substantially from the one students encounter today. Development teams were comparatively small, production pipelines remained fluid and many working practices were still evolving. Audio departments often worked alongside programmers, artists and designers in highly collaborative environments where formal boundaries between disciplines were less rigid than they later became. Bush described an atmosphere in which experimentation emerged naturally from everyday work. New hardware appeared rapidly, production tools changed continuously and every project seemed to introduce another set of technical problems that required fresh solutions. Experience remained valuable, though it rarely eliminated uncertainty.

    The computers on which players experienced those games introduced another level of unpredictability. Audio hardware varied enormously between systems, making consistent playback almost impossible to guarantee. Different sound cards reproduced music in noticeably different ways, while MIDI playback depended heavily upon whichever synthesis hardware happened to be installed inside an individual computer. A carefully balanced piece of music created inside the studio might sound dramatically different once it reached somebody else’s machine. Sound designers could control what left the studio. They could not control how it would ultimately be heard.

    This uncertainty extended well beyond music. Dialogue, sound effects and ambience all passed through hardware whose behaviour remained largely outside the control of the development team. Rather than designing for one predictable playback system, audio professionals found themselves designing for thousands of possible listening environments. Bush described this as one of the defining characteristics of early game audio. The question was rarely how a soundtrack sounded under ideal conditions. Instead, designers learned to ask whether it continued to communicate effectively when reproduced by equipment they had never encountered. The playback system itself became part of the design problem.

    Although contemporary technology has advanced enormously, the underlying challenge remains surprisingly familiar. Players now experience games through televisions, headphones, laptops, handheld consoles, mobile phones and increasingly varied listening environments, each introducing its own acoustic character. Perfect consistency remains elusive. The responsibility of the sound designer therefore extends beyond producing interesting sounds. It includes anticipating how those sounds will survive the journey from the studio to the listener.

    Bush also reflected upon the rapid transformation of production tools during this period. Early editing systems offered comparatively limited support for assembling large projects, requiring significant manual organisation and making complex revisions both time-consuming and potentially destructive. The arrival of Pro Tools transformed those workflows, allowing audio teams to edit non-destructively, manage increasingly complex sessions and collaborate more effectively. At much the same time, improvements in virtual sampling gave composers access to increasingly expressive orchestral sounds without requiring every revision to involve live performers. These developments expanded what small audio teams could realistically achieve while allowing creative ideas to evolve throughout production rather than becoming fixed at an early stage.

    The tools available to sound designers evolved just as quickly. Bush described middleware as another important step in that development. As implementation systems became more sophisticated, audio teams gradually assumed greater responsibility for how sounds behaved inside games rather than simply supplying recordings for programmers to trigger. Interactive playback, transitions and behavioural logic increasingly became part of the sound designer’s creative role. Technology expanded the possibilities available to audio departments, though it also broadened their responsibilities. Understanding implementation became almost as important as creating the sounds themselves.

    One observation from Bush’s time at Blizzard challenged another common assumption about technological progress. Greater technical capability did not necessarily encourage increasingly elaborate soundtracks. He reflected upon how musical direction gradually changed across successive projects, with later productions often favouring greater restraint rather than greater complexity. Earlier scores frequently relied upon dense orchestral textures intended to create scale and spectacle. Later work often achieved stronger dramatic results through simpler arrangements that allowed individual musical ideas greater space to breathe. Rather than filling every available moment with sound, composers became increasingly selective about where music should lead the player’s attention and where silence or restraint could prove more effective.

    The same principle appeared throughout sound design more generally. Memory budgets restricted how many sounds could be stored. Processor limitations reduced the number that could play simultaneously. Dialogue budgets limited the amount of recorded speech available to designers. Every technical restriction demanded choices. Which sounds genuinely communicated useful information? Which could be simplified without affecting the player’s experience? Which details would most influence the way a moment was perceived? Bush’s examples repeatedly suggested that successful sound design depends less upon including everything that is technically possible than upon identifying what is genuinely important for the listener.

    By this stage of the lecture, the discussion had established a way of thinking that extended well beyond the technology of any particular decade. New hardware, new software and new production methods continually alter the practical challenges facing sound designers, yet they rarely change the underlying task. Every project begins with a listener, a playback system and a collection of technical constraints that cannot simply be ignored. The role of the sound designer is to understand those conditions and create the most convincing experience possible within them.

    The relationship between creativity and constraint became considerably more tangible during Bush’s work with Sphero, where many of the assumptions underlying conventional game audio no longer applied. Working on licensed products featuring characters such as R2-D2, BB-8 and Lightning McQueen involved far more than transferring familiar techniques onto a different platform. Every sound would eventually emerge from a miniature loudspeaker housed inside a compact plastic enclosure containing motors, batteries, gears and electronic components. The finished product would be heard in kitchens, classrooms, living rooms and gardens rather than through carefully positioned studio monitors or high-quality headphones. Under those conditions, many established production practices simply ceased to be useful. The question was no longer how a sound performed inside the studio. It became how that sound survived once it reached the device for which it had actually been designed.

    Bush described changing his workflow to reflect that reality. Rather than completing the sound design and then testing it on the finished hardware, he monitored much of his work directly through the loudspeaker installed inside the product itself. Equalisation, dynamics, tonal balance and overall character were judged using exactly the same hardware that customers would eventually hear. The acoustic behaviour of the enclosure, the resonances introduced by the plastic casing and even the mechanical sounds generated by the internal motors became part of the design process. Instead of treating these characteristics as defects to be corrected afterwards, they became factors that shaped creative decisions from the beginning.

    The approach illustrates an important principle that extends well beyond embedded devices. Playback systems are never neutral. Every loudspeaker, pair of headphones, television or mobile phone colours the material passing through it. Sound designers often devote considerable attention to recording, editing and mixing, though the listening environment ultimately contributes just as much to the audience’s experience. Bush repeatedly returned to the importance of understanding where sounds will actually be heard. A design that performs beautifully on large studio monitors may communicate surprisingly little through the hardware used by most listeners. Successful sound design therefore depends not only upon creating interesting sounds, but also upon understanding the conditions under which those sounds will be experienced.

    Tiny loudspeakers presented another unavoidable challenge. Their physical dimensions simply prevented them from reproducing deep bass with any real authority. Attempting to force low frequencies through such hardware produced distortion long before it created convincing weight. Rather than attempting to overcome those physical limitations directly, Bush exploited the way listeners perceive sound. By introducing carefully controlled upper harmonics, he encouraged the auditory system to infer the presence of frequencies that the loudspeaker itself could not reproduce. The hardware remained unchanged, though the listening experience became noticeably richer.

    The solution depended upon psychoacoustics rather than brute force. Human hearing does not operate as a simple measuring device. Listeners continually reconstruct incomplete information, using harmonic relationships, timing cues and previous experience to build coherent auditory impressions. Bush’s work demonstrated how understanding those perceptual processes can prove more valuable than pursuing technically impossible specifications. The objective was never to reproduce frequencies that the loudspeaker could not generate. It was to create a convincing impression of fullness using the resources that remained available. Throughout the lecture, this distinction emerged repeatedly. Good sound design often depends less upon reproducing reality perfectly than upon understanding how listeners interpret what they hear.

    Sampling rates introduced another practical compromise. Embedded devices offered only a fraction of the storage and processing power available to contemporary games, requiring careful management of bandwidth and memory. Bush explained that these restrictions became particularly noticeable when working with robotic characters such as R2-D2, whose personality depends upon bright electronic vocalisations occupying the upper regions of the frequency spectrum. Lower sampling rates inevitably reduced the highest frequencies that could be reproduced accurately, making filtering and careful spectral management essential parts of the design process. Concepts that students often encounter as digital audio theory became everyday creative decisions affecting how expressive and recognisable the finished character would become.

    The material supplied by Lucasfilm also revealed how much organisation underpins apparently effortless performances. Bush did not receive complete scenes or finished sequences ready to be inserted into the product. Instead, he worked with an extensive collection of individual R2-D2 vocalisations drawn from the films. These recordings were not simply organised according to pitch or duration. Their emotional character proved considerably more important. Expressions of curiosity, excitement, concern, frustration and amusement were grouped together so that the robot’s responses could reflect changing situations while remaining faithful to the personality audiences already recognised.

    Randomisation played an important role, though not in the simplistic sense of allowing any sound to play at any time. Bush described carefully controlled systems that introduced variation without sacrificing recognisability. Human listeners identify repeated patterns remarkably quickly, yet behaviour that appears completely unpredictable can feel equally artificial. Convincing interactive audio therefore occupies a position between repetition and randomness. Familiar vocalisations return often enough to establish character, while subtle variations prevent those repetitions from becoming mechanical. The objective is not to surprise the listener continually, but to create the impression of a responsive and expressive personality.

    The same balance appears throughout interactive sound design. Footsteps, interface sounds, environmental ambiences and weapon effects all benefit from controlled variation rather than unlimited randomness. Collections of related recordings, small differences in pitch or timing and carefully managed playback logic often produce more convincing results than vast libraries of unrelated sounds. Bush’s examples demonstrated that believable behaviour frequently depends upon the relationships between sounds rather than the number of sounds available.

    As the lecture broadened beyond embedded devices, Bush argued that creating individual sounds represents only one part of a modern sound designer’s role. Interactive media introduces challenges that simply do not exist in linear forms such as film or television. A film editor knows exactly when every line of dialogue will be heard and how every scene will unfold. Games surrender much of that control to the player. Conversations may begin unexpectedly, be interrupted, or never occur at all. Players may spend hours exploring one environment while another moves through it in minutes. The soundtrack therefore cannot be constructed as a fixed sequence of events. It has to respond continuously to changing circumstances.

    Middleware transformed this aspect of production. Earlier generations of game development relied heavily upon programmers to implement even relatively modest audio behaviour. As middleware matured, sound designers gained much greater control over how sounds responded to events within the game itself. Playback logic, transitions, priorities and interactive behaviours increasingly became part of the sound designer’s creative responsibility. Recording remained an important part of the job, though implementation became equally significant. Designing how sounds behave proved just as important as designing the sounds themselves.

    This shift also changed the relationship between audio departments and the wider development team. Bush repeatedly emphasised that sound design does not exist in isolation. Programmers determine what information becomes available. Designers establish the systems that govern player behaviour. Writers shape dialogue, animators influence timing and movement, while artists define the visual environments within which sounds operate. Audio departments respond to all of these decisions while contributing their own expertise in return. Successful interactive soundtracks emerge through continual collaboration rather than from any single discipline working independently.

    One discussion during the lecture addressed the way sound professionals are perceived within development teams. Bush reflected on labels such as “the sound guy” or “the noise boy”, expressions that dramatically underestimate the breadth of contemporary audio practice. Modern sound designers contribute far beyond the creation of individual sound effects. They solve technical problems, shape interactive behaviour, collaborate across disciplines and influence how players ultimately experience the game. Titles such as Audio Director acknowledge that broader creative and technical responsibility.

    Questions from students later turned towards virtual reality, where many of these relationships become even more apparent. Convincing virtual environments depend upon much more than visual realism. Sound provides continuous information about distance, movement, scale and spatial relationships, allowing users to build coherent mental models of spaces extending beyond their immediate field of view. Carefully designed spatial audio therefore contributes directly to presence, orientation and immersion rather than acting as a decorative addition to the visual experience.

    Across subjects as varied as desktop games, embedded devices, robotic toys and virtual reality, Bush repeatedly returned to the same way of thinking. Every project began with an understanding of the available technology, the listening conditions and the perceptual abilities of the audience. The hardware changed dramatically throughout his career, though the questions facing the sound designer remained remarkably consistent. Rather than asking how to exploit every available technical capability, Bush continually asked what listeners actually needed to hear and how the available technology could communicate that experience most effectively.

    Across projects as different as Blizzard’s games, Sphero’s robotic products and emerging virtual reality systems, Bush consistently returned to the same set of design questions. Technology continued to change throughout his career, introducing new platforms, workflows and constraints, yet the underlying task remained remarkably stable. Successful sound design depended upon understanding how people listen, how technology behaves and how creative decisions bridge the gap between the two. Whether working with a full orchestral score, an interactive dialogue system or a miniature loudspeaker inside a robotic toy, the objective was never simply to produce impressive sounds. It was to create listening experiences that remained convincing under the conditions in which they would actually be heard.

  • How Do We Know What We Are Hearing? Professor Albert S. Bregman on Auditory Scene Analysis and Perceptual Organisation

    Albert Bregman

    How do we know what we are hearing?

    The question sounds simpler than it is. A voice is heard as a voice. A violin is heard as a violin. A passing vehicle is recognised almost immediately. Everyday listening creates the impression that sound sources reveal themselves directly. Most people rarely stop to consider how much processing has already taken place before recognition becomes possible. Professor Albert S. Bregman’s research begins from the observation that sound sources do not arrive at the ears. Acoustic mixtures do. By the time vibrations reach a listener, contributions from many different events have already combined. Voices, musical instruments, footsteps, ventilation systems, birdsong, machinery, and countless other sources may all contribute to the same signal. The auditory system must somehow determine which parts of that mixture belong together and which do not. Before Bregman’s work, hearing research had developed detailed accounts of pitch, loudness, masking, localisation, and frequency analysis. Considerably less attention had been paid to a more fundamental question. How does a listener determine what produced a sound?

    Bregman did not begin with a theory. He began with a puzzle. During memory experiments involving sequences of short sounds, he noticed that listeners often perceived groupings that were not physically present within the stimulus itself. Sounds sharing similar characteristics appeared to organise themselves into separate perceptual streams. The observation recalled ideas from Gestalt psychology, where visual elements combine into structures that cannot be understood simply by examining their individual parts. What began as an unexpected observation gradually became a larger problem. If listeners organise sounds into streams, how does that organisation occur? More importantly, what role does it play in perception itself? Bregman often approached the issue through analogy. Imagine standing beside a lake while observing only two floating markers moving up and down on the water’s surface. The movement provides evidence that something has happened, though many explanations remain possible. A boat may have passed nearby. Several boats may be moving in different directions. Wind may be disturbing the surface. Something may have fallen into the water. The available evidence does not identify the cause. Any conclusion depends upon inference. According to Bregman, hearing presents a similar challenge. The ears receive information about acoustic activity, though they do not receive direct information about the events that produced it. From patterns of pressure variation reaching two eardrums, listeners somehow infer the existence of voices, instruments, machines, animals, and other sound-producing events. Nothing in the signal arrives labelled. The auditory system must determine which acoustic components belong to the same source.

    Questions of speech perception, localisation, attention, and communication all depend upon this process. Before speech can be understood, before a melody can be followed, and before a sound source can be identified, the auditory system must first determine which acoustic components belong together. Organisation is therefore not one stage among many. It provides the conditions under which many other aspects of perception become possible. This perspective led Bregman towards what became known as auditory scene analysis. The term reflects an analogy with vision. Just as visual perception involves identifying objects within a visual scene, auditory perception involves identifying sound-producing events within an acoustic scene. The challenge lies in the fact that sound sources combine before reaching the listener. The auditory system therefore faces a decomposition problem. It must separate a complex mixture into components that plausibly belong to distinct events. A central claim running throughout the lecture was that perception involves more than detecting acoustic information. It also involves organising that information. Bregman’s demonstrations repeatedly returned to this point. Listeners often assume that qualities such as rhythm, melody, pitch, loudness, timbre, and location belong directly to sounds themselves. His examples suggested a more complicated picture.

    Auditory stream segregation provides one illustration. Under certain conditions, listeners stop hearing a single sequence of sounds and begin hearing multiple independent streams. Once this occurs, rhythms that were previously obvious may disappear. New rhythmic structures emerge. Melodic patterns change. The acoustic signal remains unchanged, though the perceptual outcome does not. Bregman’s demonstrations suggested that the consequences extend much further than rhythm or melody alone. Again and again, he returned to the idea that many perceptual properties depend upon how sounds are grouped. Listeners often assume that pitch, loudness, timbre, and spatial location belong directly to sounds themselves. Yet these properties can also be influenced by the way acoustic components are assembled into perceptual objects. When those groupings change, perception may change even when the underlying stimulus remains constant. This claim sits near the centre of auditory scene analysis. The framework is not simply concerned with separating one sound source from another. It is concerned with how perceptual objects are formed in the first place. Before listeners can judge the loudness of a sound, identify its pitch, recognise its timbre, or determine its location, the auditory system must first decide which components belong together. The resulting structure shapes many of the properties that listeners subsequently experience. From this perspective, perception becomes a problem of interpretation. Faced with an acoustic mixture, the auditory system must determine which explanation is most plausible. What listeners hear is not a direct copy of the physical world. It is the outcome of a process through which the auditory system attempts to reconstruct the events most likely to have produced the available evidence.

    Bregman argued that listeners exploit regularities commonly found in the physical world. Certain acoustic relationships provide evidence that components are likely to originate from the same source. Harmonicity offers one example. Many naturally occurring sounds contain frequency components related by simple numerical ratios. When such relationships are detected, the auditory system often groups those components together. Similar reasoning underlies what Bregman described as common fate. Components that begin together, change together, or move together over time frequently appear to belong to the same event. These principles do not guarantee correct interpretation. Rather, they provide strategies that usually correspond with the structure of the physical world. Auditory scene analysis is therefore concerned with probability rather than certainty. The auditory system rarely knows exactly what caused a sound. It generates interpretations that are likely to account for the available evidence. Most of the time those interpretations correspond closely enough to events in the environment that listeners remain unaware that any interpretation has occurred at all. Throughout the lecture, Bregman emphasised that these organisational processes usually pass unnoticed. Listeners rarely experience themselves as constructing interpretations. The world appears already divided into voices, instruments, footsteps, vehicles, and other familiar sources. Auditory scene analysis directs attention to the work required to produce that impression. The apparent simplicity of hearing may be one reason the problem remained difficult to recognise. Successful perception conceals many of the processes that make it possible.

    Music occupied an interesting position within the lecture. Bregman suggested that composers had discovered practical consequences of auditory organisation long before psychologists attempted to explain them. Counterpoint, orchestration, and performance practice frequently involve maintaining distinctions between perceptual streams or encouraging sounds to fuse into larger structures. Musical traditions therefore provide a long record of experimentation with the same organisational tendencies that auditory scene analysis later sought to describe. Music also offers situations in which these processes become unusually apparent. Changes in perceptual organisation can alter the melodies and rhythms listeners hear, making it possible to observe principles that often remain hidden during everyday listening. Bregman was not suggesting that composers were unconsciously applying psychological theory. Rather, centuries of musical practice had encountered many of the same perceptual constraints that later became objects of scientific investigation.

    Yet music represented only one instance of a broader phenomenon. Following a conversation in a crowded room, recognising a familiar voice over the telephone, locating a sound source in a busy environment, distinguishing one instrument from another, and understanding speech in noise may appear to involve different problems. Bregman’s framework suggested that each depends upon a prior act of organisation. Auditory scene analysis altered the relationship between many areas of hearing research by drawing attention to this common foundation. Rather than treating speech, music, localisation, and auditory attention as entirely separate domains, the framework highlighted organisational processes upon which they all depend. Seen in this way, auditory scene analysis is not merely a theory about particular auditory illusions or laboratory demonstrations. It addresses a question that sits beneath much of auditory perception research. How does a listener move from an undifferentiated acoustic mixture to a world populated by distinct events, objects, and sources?

    The framework also shifted attention away from sound as a purely physical phenomenon and towards perception as a process of inference. Earlier approaches often focused on the contents of the acoustic signal. Bregman drew attention to a prior question. Before a listener can recognise a voice, identify an instrument, understand speech, or respond to a warning signal, the auditory system must first decide what probably caused the sound.

    The answer is usually reached so quickly that the problem remains unnoticed. Voices appear as voices. Instruments appear as instruments. Bregman’s work suggests otherwise. Listening depends upon a continual process through which the auditory system constructs explanations from incomplete evidence. Most of the time those explanations correspond closely enough to the surrounding environment that hearing feels direct and effortless.

  • Can Sound Quality Be Measured? David Bowen on Psychoacoustics, Product Design, and Human Perception

    David Bowen

    Can sound quality be measured?

    For engineers, the question seems perfectly reasonable. Modern acoustic analysis can measure sound pressure levels, frequency content, vibration, loudness, roughness, sharpness, tonal components, and countless other characteristics. Faced with such an abundance of data, it is tempting to assume that product sound quality can ultimately be reduced to a collection of numbers. If we can measure a sound accurately enough, surely we can determine whether it is good or bad.

    During his online guest lecture for Edinburgh Napier University, David Bowen spent much of his time explaining why the answer is not nearly so simple. Across more than three decades working in acoustics, vibration, psychoacoustics, and product sound quality, Bowen has helped organisations understand how people respond to the sounds products make. Throughout a career spanning industrial research, consultancy, and product development, he has worked at the intersection of acoustics, psychoacoustics, engineering, and product design. Again and again, his examples pointed towards the same conclusion. Sound can be measured. Sound quality cannot.

    This distinction formed the foundation of the lecture. Sound quality, Bowen argued, is not a property of a product. It is a response of people. A microphone does not experience annoyance. A sound level meter does not perceive quality. Only listeners do. Understanding product sound quality therefore requires understanding both the physical sound and the human beings who hear it. Difficulties emerge as soon as engineers attempt to connect measurements to human responses. Bowen illustrated this challenge through examples in which sounds with similar measured levels produced dramatically different subjective reactions. A pure tone, broadband noise, an organ note, or a piece of industrial machinery may all produce similar sound levels, yet listeners often describe them in very different ways. Some sounds are judged pleasant. Others are irritating. Some feel powerful. Others feel weak. Part of the difficulty lies in the way human hearing operates. Psychoacoustics has demonstrated repeatedly that listeners do not experience sound in a simple or linear fashion. Sensitivity varies across frequencies. Loudness does not increase proportionally with sound pressure. Perception depends not only upon what reaches the ears but also upon how the brain interprets it. Measuring the sound itself is only part of the problem.

    Bowen illustrated this point through several examples that challenge common assumptions about listening. Human memory for loudness is surprisingly limited. When listeners hear two sounds separated by even a relatively short interval, their ability to compare levels accurately begins to deteriorate. Judgements become influenced by expectation, context, and interpretation rather than purely acoustic characteristics. Even when measurements are reliable, the perceptual processes through which listeners experience those sounds remain considerably more complex.

    For decades, researchers attempted to bridge this gap through increasingly sophisticated metrics. If sound pressure level proved insufficient, perhaps loudness would provide a better predictor. If loudness proved inadequate, perhaps perceived noisiness, roughness, sharpness, or other psychoacoustic measures would help. Each new metric offered valuable insights, yet each also revealed new limitations. Bowen discussed how the arrival of jet aircraft exposed weaknesses in existing approaches to noise evaluation, prompting the development of measures intended to capture perceived noisiness more effectively. Those measures improved predictions in some contexts while proving less successful in others. Similar challenges emerged across industrial machinery, transportation systems, and consumer products. As soon as one perceptual factor appeared understood, another emerged. Listening proved stubbornly resistant to simple description.

    Bowen’s career spans a period during which acoustics increasingly recognised that physical measurements alone could not explain human responses. Successive generations of psychoacoustic metrics attempted to narrow the gap between measurable sound and perceived quality. Each represented an improvement upon what came before, though none provided a complete solution. Human perception remained influenced by context, expectation, memory, meaning, and experience. The history of product sound quality therefore became, in part, a history of increasingly sophisticated attempts to understand how people listen. Similar problems emerge elsewhere. A piano recording played backwards retains many of its measurable characteristics, yet listeners immediately perceive something fundamentally different. What sounds like a piano becomes something closer to an organ. Human listeners detect meaningful changes that conventional measurements often struggle to explain. Again and again, perception proves more complicated than measurement.

    If measurements alone cannot fully predict how people will respond, a difficult question follows. How should products be designed?

    For Bowen, the answer lies in listening. Much of the lecture focused on sound quality jury testing, a methodology that places human listeners at the centre of the evaluation process. Rather than asking which sound measures best, researchers ask which sound people prefer, which sound communicates particular qualities, and which sound supports the intended experience of a product.

    This creates an interesting tension. Engineers naturally seek measurements. Manufacturers want targets that can be specified, monitored, and improved. Product development processes favour quantities that can be compared and optimised. Yet listeners remain the ultimate judges of quality. No matter how sophisticated a measurement becomes, a product succeeds or fails according to how people experience it. Jury testing therefore emerged not as a rejection of engineering but as a recognition that engineering alone could not answer every question.

    Carefully designed listening tests provide information that measurements alone cannot. This approach complements rather than replaces traditional acoustic analysis. Measurements help researchers understand what a product is doing acoustically. Listening tests help them understand how people respond. Product sound quality emerges through the relationship between these two perspectives. Designing listening tests of this kind is far from straightforward. Participants must be selected carefully. Stimuli need to be prepared consistently. Presentation order can influence responses. Questions must be designed in ways that avoid leading participants towards particular conclusions. Statistical analysis becomes essential if meaningful patterns are to emerge from the resulting data. Throughout the lecture, Bowen emphasised that listening tests require as much methodological care as any engineering measurement.

    One particularly interesting aspect of this work involves the creation of what Bowen described as virtual products. Rather than constructing numerous physical prototypes, researchers can isolate individual sound components and manipulate them independently. Motor noise, airflow noise, pump sounds, valve sounds, and other elements can be adjusted before being recombined into new versions of the product. Listeners can then evaluate these alternatives, allowing researchers to explore how specific design decisions influence perceived quality without repeatedly redesigning the product itself.

    One of the lecture’s most illuminating examples involved front-loading washing machines. Modern washing machines generate a wide range of sounds, including motor noise, water movement, pumping systems, valves, and the movement of clothes within the drum. Traditional noise control might focus simply on reducing these sounds wherever possible. Bowen’s research adopted a different approach. Rather than treating the machine as a single noise source, the different sounds produced during filling, washing, draining, and spinning were analysed separately. Each stage introduced its own acoustic characteristics and potential design challenges. Water movement, pump operation, motor behaviour, valve activity, and the interaction between clothes and the drum all contributed differently to listener perceptions. Individual sound components were isolated and manipulated. Participants evaluated these variations through listening tests, allowing researchers to identify which sounds influenced acceptability most strongly.

    The resulting data could then be analysed using statistical models that linked changes in specific sound components to listener ratings. One of the most interesting aspects of this work involved the creation of response-surface models that allowed engineers to visualise how perceived quality changed as different sound characteristics were adjusted. Rather than producing a simple pass-or-fail result, the models created maps of possible design outcomes. Engineers could explore how increasing one characteristic while reducing another might influence listener responses. Product sound quality rarely involves finding a single perfect solution. Designers must balance acoustic quality against manufacturing constraints, performance requirements, reliability considerations, and cost limitations. Statistical modelling provides a way of navigating these trade-offs while retaining a clear understanding of how design decisions influence perception.

    Similar principles appeared in Bowen’s work on vacuum cleaners. Consumers often claim that they want quieter products, yet a vacuum cleaner that becomes almost silent introduces a different problem. Users may begin to question whether it is working properly. Certain sounds communicate power, airflow, and cleaning effectiveness. Eliminating every sound is not necessarily desirable. In this case, the challenge is not simply reducing noise but preserving those aspects of the sound that contribute positively to the user’s perception of performance. What emerges from Bowen’s examples is a view of product sound that differs significantly from traditional approaches to noise control. Sounds are not merely by-products of mechanical systems. They communicate information about performance, condition, reliability, quality, and identity. A washing machine, a vacuum cleaner, a refrigerator, and an aircraft each occupy different places in people’s lives. Listeners bring different expectations to each. A refrigerator should not sound like a lawnmower. Equally, a lawnmower should not sound like a refrigerator. The challenge is therefore not simply reducing sound, but designing sounds that make sense within a particular context.

    Seen in this light, product sound quality becomes a remarkably human problem. Engineers can measure sound with extraordinary precision. Researchers can develop increasingly sophisticated psychoacoustic models. Statistical techniques can reveal relationships between acoustic characteristics and listener preferences. Yet none of these tools removes the need to understand people. Sound quality emerges not from products alone but from the relationship between products and listeners. What emerged from the lecture was a challenge to a familiar engineering instinct. Faced with a difficult problem, engineers naturally seek better measurements. Bowen’s work suggests that measurements remain essential, though they are not enough on their own. Product sound quality exists at the point where physical acoustics meets human perception. This creates an unusual situation. Few areas of engineering depend so heavily upon subjective judgement while simultaneously demanding rigorous measurement. Product sound quality requires microphones, analysers, statistical models, listening tests, psychoacoustic theory, and human listeners. Remove any one of these elements and the picture becomes incomplete.

    Perhaps this is why the question that opened the lecture remains so difficult to answer. Can sound quality be measured? David Bowen’s career suggests that the answer is both yes and no. Sounds can be measured with extraordinary precision. Human responses can be studied, modelled, and predicted. Yet quality itself ultimately emerges through experience. The most successful products are not necessarily the quietest products, nor the products with the best acoustic measurements. They are the products whose sounds make sense to the people who use them. In the end, product sound quality is not really about sound at all. It is about understanding listeners.

  • Who Are We Designing For? Professor Bruce Walker on Sound, Accessibility, and Human-Centred Design

    Bruce Walker

    Who are we designing for?

    At first glance, the answer appears obvious. Designers create products for users. Engineers build systems to help people accomplish tasks. Technology exists to solve problems. Yet during his online guest lecture for Edinburgh Napier University, Professor Bruce Walker repeatedly returned to examples suggesting that the answer is often more complicated than it first appears. Again and again, he described situations in which technically impressive systems failed to account for the realities of the people expected to use them. A solution might work perfectly according to engineering specifications while proving frustrating, distracting, or simply undesirable in practice. Across projects involving navigation, education, museums, accessibility, sonification, and auditory interfaces, Walker argued that successful design begins not with technology but with understanding human needs.

    Sound provided the central thread running through the lecture. Many people associate auditory interfaces with simple alerts and alarms. Computers beep. Phones ring. Vehicles issue warning tones. Yet Walker demonstrated that sound can serve far more sophisticated purposes. It can guide navigation, communicate data, support education, enable accessibility, assist decision-making, and provide entirely new ways of interacting with technology. These possibilities emerge not from adding sounds indiscriminately but from carefully considering what information people need, when they need it, and how they can use it effectively.

    This emphasis on understanding users before designing solutions appeared throughout the lecture. These broader questions became particularly visible in Walker’s discussion of the SWAN project, the System for Wearable Audio Navigation. The goal was deceptively simple. Could sound help people navigate when they could not rely on vision? Blind users are an obvious example, though Walker deliberately framed the problem more broadly. Firefighters moving through smoke-filled buildings, soldiers operating at night, divers underwater, and workers engaged in visually demanding tasks may all find themselves unable to look or unable to see. Rather than designing exclusively for a particular group, the project focused on a shared perceptual challenge.

    Approaching the problem in this way immediately changed the nature of the design process. Navigation might seem like a familiar activity, something most people perform every day without conscious thought. Yet once the team began analysing the task carefully, they discovered layers of complexity hidden beneath the surface. People need to know where to go, though they also need information about obstacles, changes in terrain, landmarks, hazards, and points of interest. Navigation is not simply a matter of moving from one location to another. It involves understanding an environment while continuously making decisions within it.

    The resulting system employed spatialised audio beacons that users could follow through space. Walker compared them to a virtual carrot suspended ahead of the listener. Rather than receiving a sequence of verbal instructions, users simply moved towards a sound source. When a turn became necessary, the sound shifted position accordingly. The concept appears elegant partly because it exploits abilities listeners already possess. Humans are remarkably good at locating sounds. Rather than teaching an entirely new interaction technique, the system builds upon existing perceptual skills.

    What makes the project particularly revealing, however, is the extent to which users shaped its development. Early assumptions frequently proved incorrect. Designers initially believed they should describe surface transitions in detail, informing users when they were moving from pavement to grass or from one surface to another. Users quickly pointed out that such information was often redundant. They already knew where they were standing. What mattered was knowing what was coming next. By listening carefully to users rather than insisting upon their original assumptions, the team produced a more efficient and less intrusive system.

    This pattern appeared repeatedly throughout the lecture. Successful auditory interfaces emerge through collaboration, observation, and evaluation rather than through technological enthusiasm alone. Walker repeatedly emphasised the importance of testing systems with real users performing real tasks. Maps of navigation paths, performance data, error rates, and subjective feedback all played important roles in understanding whether a design genuinely worked. The question was never whether a system could be built. The question was whether it improved people’s ability to accomplish what they were trying to do.

    Perhaps nowhere was this philosophy more apparent than in the team’s work with bone-conduction audio. Navigation systems often rely upon stereo or spatial audio, which typically requires headphones. Yet many users rejected conventional headphones immediately. Blind people rely heavily upon environmental sounds. Firefighters need to hear what is happening around them. Covering the ears solved one problem while creating another. Rather than treating this as an unavoidable limitation, the researchers reconsidered the entire system. Bone-conduction devices allowed spatial audio to be delivered without blocking environmental awareness. Once again, the solution emerged not from pursuing technology for its own sake but from understanding the realities of users’ lives.

    Walker extended these ideas beyond navigation into the design of auditory menus and interfaces. Modern computer systems contain large amounts of information organised visually through menus, icons, scroll bars, and navigation structures. Translating these elements into sound presents significant challenges. Simply reading everything aloud through text-to-speech quickly becomes inefficient and frustrating. Long contact lists, extensive music libraries, and complex software systems require more sophisticated approaches.

    Many of the solutions developed by Walker and his collaborators demonstrate an intriguing combination of technical ingenuity and psychological insight. Spearcons, for example, compress spoken words into highly abbreviated auditory cues that users rapidly learn to recognise. Spindex systems provide indexing sounds that help listeners move efficiently through large collections without hearing every item in sequence. Whispered speech can indicate unavailable menu items while preserving the overall structure of an interface. These innovations are clever, though their importance lies less in their novelty than in their effectiveness. Each emerged through extensive experimentation designed to determine what users actually understood and preferred. What makes this work particularly interesting is that it was never simply about making visual interfaces audible. Instead, it explored how auditory interfaces might exploit the strengths of listening itself. Users do not experience sound in the same way they experience vision, and successful interfaces acknowledge that difference rather than treating audio as a substitute for a screen.

    The lecture repeatedly highlighted a distinction between engineering and design. Engineering can produce systems that function correctly. Design concerns whether people will actually want to use them. Walker discussed several examples of technically impressive systems that failed precisely because they neglected this distinction. Some provided too much information. Others demanded excessive attention. Many ignored the broader contexts within which people operate. A system may be capable of delivering enormous amounts of information, though that does not necessarily mean people want to receive it.

    Questions of accessibility broadened these concerns further. Much of Walker’s work focuses on enabling participation rather than merely providing access. He described projects supporting education for blind students, making scientific information more accessible, and improving experiences within museums and aquariums. These examples revealed another recurring theme. Accessibility is not simply about removing barriers. It is about ensuring that people can engage meaningfully with experiences, opportunities, and ideas.

    His work within museums and aquariums illustrates this particularly well. Modern cultural institutions often provide physical access while leaving informational and emotional access largely unresolved. A blind visitor may be able to enter an aquarium, though the experience remains fundamentally visual. Standing before an enormous tank filled with whale sharks and rays offers little if the most important aspects of the exhibit remain inaccessible. Walker’s team explored ways of using tracking systems, sonification, narration, and auditory displays to communicate not only what was present but what was happening. The objective was not merely to describe the environment. It was to create opportunities for engagement, curiosity, and wonder.

    Educational projects revealed similar concerns. Throughout the lecture, Walker repeatedly returned to the distinction between access and participation. Providing information is only one part of inclusion. Students also need opportunities to explore, question, discover, and develop understanding independently. Whether working with scientific data, classroom materials, museum exhibits, or public spaces, the challenge remained remarkably consistent. How can information be presented in ways that support meaningful engagement rather than passive reception? Accessibility, in this sense, becomes a question of design quality rather than a specialised feature introduced at the end of a project.

    Underlying many of these projects is the field of sonification, the practice of representing information through sound. Walker described sonification as both a design challenge and a research problem. Any attempt to translate data into sound requires decisions about mapping, scaling, timing, context, and interpretation. Should temperature be represented through pitch, loudness, or tempo? How should complex information be organised so that listeners can understand it? These questions have no universal answers. Effective solutions depend upon understanding both the data and the people expected to interpret it.

    One reason sonification remains challenging is that many listeners have relatively little experience interpreting information through sound. Graphs, charts, and maps are familiar cultural forms. Auditory representations are far less common. Designers therefore need to balance learnability with expressiveness. A system may communicate information accurately while remaining difficult to interpret. Conversely, a system may sound appealing while conveying very little. Walker’s research repeatedly demonstrated that effective sonification emerges through iterative testing with users rather than through theoretical assumptions alone.

    Such challenges reveal why Walker remains sceptical of simplistic approaches to auditory design. Throughout the lecture, he criticised the tendency to reduce audio interfaces to collections of arbitrary beeps and alerts. Sound possesses enormous communicative potential, though realising that potential requires careful thought. Designers must consider attention, context, usability, aesthetics, cultural expectations, and human behaviour. A sound that performs well in a laboratory may fail completely in everyday life. A technically accurate representation may prove ineffective if users cannot interpret it.

    The phrase “beeps and bops” became a useful shorthand for this problem. Many technologies employ sound only at the most superficial level, relying upon alerts, warnings, and notifications while overlooking the richer possibilities of auditory interaction. Walker’s work points towards a broader conception of sound, one capable of supporting navigation, exploration, learning, communication, and discovery. The challenge is not simply adding sound to technology. It is designing meaningful auditory experiences.

    Towards the end of the discussion, Walker reflected on what he described as a “failure of imagination” in technology design. Sometimes designers struggle to imagine how people actually live with technologies. At other times, users struggle to imagine possibilities that do not yet exist. Successful innovation requires navigating both challenges simultaneously. Revolutionary technologies rarely emerge through user requests alone. Yet genuinely useful technologies also cannot emerge through engineering in isolation. Design becomes a process of bridging these perspectives.

    Looking back across the lecture, what emerges most clearly is not a story about auditory interfaces but a broader philosophy of design. Sound happens to be the medium through which Professor Walker explores these questions, though the underlying principles extend much further. Navigation systems, auditory menus, museum exhibits, educational technologies, sonification projects, and accessibility tools all reveal the same challenge. Technologies succeed not when they demonstrate technical sophistication but when they become meaningful parts of human activity.

    Perhaps this is why Walker repeatedly resisted framing accessibility as a specialised concern. The challenges faced by blind users, firefighters, drivers, students, museum visitors, and countless others often reveal broader truths about human interaction with technology. Designing for specific needs frequently produces insights that benefit everyone. When designers stop asking what a system can do and start asking what people need, entirely new possibilities begin to emerge.

    Throughout the lecture, examples ranging from spatial navigation to aquarium exhibits pointed towards the same conclusion. Successful technologies rarely begin with devices, software, algorithms, or interfaces. They begin with people. Understanding how people listen, learn, move, explore, communicate, and make decisions provides the foundation upon which everything else is built.

    For Professor Bruce Walker, the future of auditory interfaces does not lie in adding more sounds to the world. It lies in understanding how sound can help people navigate, learn, communicate, discover, and participate more fully in the experiences around them. The technology matters. The research matters. The engineering matters. Yet each ultimately serves a more fundamental question, one that quietly shaped the entire lecture from beginning to end: who are we designing for?

  • How Do We Know What Sounds Good? Dr Geoff Martin on Loudspeaker Design and Human Hearing

    Geoff Martin

    What does a good loudspeaker actually do?

    At first glance, the answer seems obvious. A loudspeaker should reproduce sound accurately. It should introduce as little distortion as possible, deliver a flat frequency response, and remain faithful to the original recording. These ideas are deeply embedded within audio culture. Specifications are compared, measurements are analysed, and products are often judged according to how closely they approach technical ideals. Yet Dr Geoff Martin’s guest lecture at Edinburgh Napier University suggested that the question is considerably more complicated than it first appears. Dr Martin, Principal Tonmeister at Bang & Olufsen, spends much of his professional life developing loudspeakers and television audio systems. Throughout the lecture he discussed cabinet volumes, amplifier power, driver behaviour, diffraction, directivity, prototype development, and measurement techniques. Beneath these technical details, however, lay a much broader question. If loudspeakers are ultimately designed for listeners, then how should engineers balance what can be measured against what people actually hear?

    That question has shaped Dr Martin’s career from the beginning. Before joining Bang & Olufsen, his doctoral work explored what he described as a phenomenological model for acoustic simulation. Rather than attempting to recreate every physical characteristic of a real concert hall, the objective was to create something listeners would perceive as convincing. A simulation could differ from reality in measurable ways while still producing an experience that sounded authentic. This distinction between physical accuracy and perceptual accuracy quietly reappeared throughout the lecture, surfacing in discussions of room acoustics, loudspeaker behaviour, directivity, and listening tests. Although the presentation focused on loudspeaker development, the deeper theme concerned a problem that extends across audio engineering as a whole. Sound is a physical phenomenon that can be measured with extraordinary precision. Listening is a human experience that cannot be reduced quite so easily.

    Much of the lecture examined how a loudspeaker is actually developed. Popular discussions of audio technology often imply that engineers begin with a clear target before gradually refining a design until it reaches perfection. Dr Martin described something rather different. Loudspeaker development begins not with solutions but with constraints. How much will the product cost? How large can it be? How loudly should it play? How low should it reproduce bass frequencies? How much internal volume is available? How much amplifier power can be accommodated? Such questions emerge long before the final product exists. Acoustic engineers, industrial designers, product managers, manufacturers, and marketers all contribute to the process. Every decision influences every other decision. A larger cabinet may improve low-frequency performance while creating industrial design challenges. A smaller enclosure may look elegant while limiting acoustic capability. Additional amplifier power may improve output levels while increasing cost and heat. Loudspeaker design therefore becomes a process of balancing competing priorities rather than pursuing a single ideal.

    For this reason, development proceeds through a series of prototypes. Early versions frequently employ off-the-shelf drivers mounted within simple enclosures that approximate the intended cabinet volume. At this stage, nobody is trying to create the finished product. Engineers are asking questions. Does the concept possess sufficient acoustic potential to justify further development? Is the enclosure volume realistic? Can the desired frequency range be achieved? Dr Martin compared this process to testing an engine outside a vehicle. Nobody is concerned with comfort, aesthetics, or handling characteristics. The objective is to establish whether enough performance exists to make further investment worthwhile. As development continues, the questions become increasingly specific. Drivers are modified. Internal structures change. Cabinet geometry evolves. Diffraction effects emerge. Resonances are identified and controlled. Measurements reveal new problems while prototypes reveal new possibilities. Progress rarely follows a straight line. Instead, the process resembles a conversation between engineering decisions and acoustic consequences, with each iteration producing a slightly deeper understanding of the system being developed.

    What makes this process particularly interesting is that measurements alone never provide all the answers. Loudspeaker development relies heavily upon objective data. Engineers measure frequency response, distortion, directivity, impedance, output capability, and countless other parameters. Without such measurements, development would quickly descend into guesswork. Yet Dr Martin repeatedly returned to a simple observation that changes how these measurements should be interpreted. Real listeners do not experience loudspeakers in anechoic chambers. They experience them in rooms.

    That observation may sound almost trivial, though its implications are profound. When a listener sits in a living room, only part of what reaches the ears comes directly from the loudspeaker. Sound also reflects from walls, ceilings, floors, windows, furniture, and countless other surfaces. Every room participates in the listening experience. A loudspeaker therefore does not simply radiate sound forwards towards a listener. It radiates sound into an environment. Once those reflections begin interacting with direct sound, the listening experience becomes considerably more complicated than a single frequency response measurement might suggest.

    This is why Dr Martin devoted considerable attention to directivity. Many audio discussions focus almost exclusively on what happens directly in front of a loudspeaker. Place a microphone on axis, measure the response, and examine the resulting graph. Such measurements remain important, though they tell only part of the story. Engineers also need to understand how sound is distributed throughout space. How much energy radiates to the sides? How much travels upwards and downwards? How does this behaviour change with frequency? To answer these questions, loudspeakers are measured repeatedly while being rotated through hundreds of positions, producing detailed maps of acoustic radiation. The resulting data reveals how a loudspeaker interacts not only with listeners but also with rooms.

    This shift in perspective transforms the problem entirely. Two loudspeakers may produce remarkably similar measurements directly in front of the listener while sounding quite different in real environments. The reason often lies in what happens away from the central listening position. A loudspeaker that distributes energy broadly throughout a room creates a different pattern of reflections from one that concentrates energy more narrowly. Those reflections influence spaciousness, localisation, tonal balance, and listener perception. Suddenly, the loudspeaker is no longer just a source of sound. It becomes part of a larger acoustic system that includes the room itself.

    At this point the lecture moved beyond engineering and into psychoacoustics. Dr Martin argued that directivity influences more than tonal characteristics. It also shapes how listeners perceive space. Human beings routinely use reflections to estimate the distance of sound sources. Outdoors, where reflections are relatively limited, sounds often appear perceptually closer than equivalent sounds heard indoors. Rooms provide information about scale, distance, and location through the reflections they generate. Loudspeakers participate in these same perceptual processes. A design that radiates energy widely into a room can produce a different impression of distance from one that concentrates energy more narrowly, even when other measurements remain similar.

    One particularly memorable example involved speech reproduction. Under certain circumstances, different frequency components within a voice can appear to occupy slightly different perceptual distances. The recording itself remains unchanged. The effect emerges from the loudspeaker’s changing directivity across the frequency spectrum. Some elements of the voice radiate broadly while others become increasingly directional. Listeners may not consciously identify the source of the discrepancy, though they often perceive something unusual. Once noticed, the effect can become difficult to ignore. Examples such as these reveal why loudspeaker design cannot be reduced to frequency response curves alone. Human hearing does not experience isolated measurements. It experiences integrated perceptual events in which distance, localisation, spaciousness, timbre, and context continuously interact.

    Seen in this light, many of the lecture’s apparently technical discussions acquire a different significance. Cabinet diffraction is not merely a measurement problem. Driver placement is not simply a mechanical decision. Directivity is not just another engineering specification. Each ultimately influences how listeners interpret acoustic information. A loudspeaker cannot be understood solely by examining what happens directly in front of it. It must also be understood in terms of how it interacts with a room and how listeners interpret the resulting acoustic information. Directivity, reflections, diffraction, frequency response, and cabinet design are not independent concerns. They are different parts of the same perceptual problem.

    This helps explain why loudspeaker development remains such an iterative process. Engineers measure, build, listen, modify, and measure again. Each prototype reveals something about the relationship between the physical behaviour of the loudspeaker and the way that behaviour is ultimately perceived. Better measurements improve understanding, though they do not eliminate the need for listening. Listening remains the reason the measurements exist in the first place.

    Looking back across the lecture, what emerges most clearly is not a story about loudspeakers but a story about the limits of measurement. Measurements remain indispensable. Without them modern loudspeaker design would be impossible. Yet measurements alone cannot answer the question that matters most. They can describe what a loudspeaker does. They cannot completely describe what it is like to hear it.

    That gap between measurement and perception is where much of loudspeaker design actually happens.

  • Designing Fear: Matt Yocum on Horror, Tension, and the Psychology of Sound

    Matt Yocum

    What is the fastest way to make a horror film stop being scary?

    Matt Yocum’s answer was immediate: mute it.

    At first, the response feels almost too simple. Horror cinema is often discussed in terms of monsters, visual effects, darkness, violence, or shock. Yet remove the soundtrack and something fundamental changes. The creature remains on screen. The corridor remains dark. The threat still exists. What disappears is much of the tension. Anticipation begins to weaken. The feeling that something terrible might be about to happen gradually fades away. For Yocum, whose career has included sound design work across film and television, this observation reveals something important about the role of sound in horror. Sound design is not simply about creating interesting sounds. It is about shaping emotion. Throughout his guest lecture at Edinburgh Napier University, whether discussing creature design, immersive audio, audience psychology, or jump scares, a remarkably consistent idea emerged. Horror is not primarily about making audiences hear frightening things. It is about making them feel uncertain about what might happen next.

    That distinction helps explain why some of the most effective moments in horror involve remarkably little happening at all. A character walks slowly down a hallway. A door stands slightly ajar. An empty room appears entirely ordinary. Nothing overtly threatening is visible, yet audiences become increasingly uncomfortable. According to Yocum, much of horror operates through tension and release. Viewers are encouraged to anticipate an event before that event actually arrives, and sound plays a central role in constructing that anticipation. Environmental detail begins to disappear. The soundtrack becomes quieter. Attention narrows. Audiences recognise the pattern immediately. Years of watching horror films have taught them that something is coming. A character approaches a door, the atmosphere tightens, and the audience braces itself for the inevitable scare. The door opens and nothing is there. Relief briefly returns, only for the real scare to arrive moments later when attention has already begun to relax. Horror repeatedly exploits this relationship between expectation and uncertainty. Audiences respond not only to what they hear, but also to what they believe they are about to hear.

    Silence therefore occupies a surprisingly important position within horror sound design. Although the genre is often associated with loud impacts and sudden shocks, Yocum argued that removing sound can be just as effective as adding it. As environmental information falls away, attention becomes focused on the sounds that remain. Breathing becomes more noticeable. Footsteps acquire greater significance. The creak of a floorboard suddenly feels loaded with meaning. None of these sounds are inherently frightening. Their significance emerges through context. A footstep heard in a crowded shopping centre communicates something very different from a footstep heard in an empty house late at night. Horror succeeds by manipulating those relationships, encouraging audiences to reinterpret ordinary sounds as signs of vulnerability, danger, or uncertainty. Rather than overwhelming viewers with information, effective sound design often achieves more through careful restraint. The audience begins searching for clues, assigning importance to small details, and constructing explanations from incomplete information. In many respects, horror is less concerned with frightening sounds than with the psychology of listening itself.

    Questions of interpretation also emerged throughout Yocum’s discussion of creature design. Audiences often imagine creature sound as a process of inventing something entirely new, though the reality is frequently more complicated. Effective creature design begins not with software, plug-ins, or signal processing, but with observation. How large is the creature? How does it move? Does it walk, crawl, slither, or fly? Does it possess lungs? How much does it weigh? What sort of anatomy produces its sounds? Such questions help ground fictional beings within believable worlds. Sound gives visual effects a sense of physical presence. A creature that appears enormous on screen can feel surprisingly weightless without appropriate sonic support. Movement, impacts, breathing, and vocalisation all contribute to the illusion that something genuinely occupies space. The task is not simply to create an unusual sound. It is to persuade audiences that a fictional entity belongs within the world they are experiencing.

    One of the most memorable moments in the lecture emerged when a student described creating a creature vocalisation from the sound of a restaurant toilet flush. Rather than dismissing the idea, Yocum praised the approach. Organic source material, he argued, often provides richer creative possibilities than excessive processing. A toilet flush already contains qualities that resemble breathing, resonance, and vocalisation. More importantly, it originates in the physical world. Throughout the lecture, Yocum repeatedly returned to the value of starting with interesting source material rather than attempting to manufacture complexity through endless layers of effects. This preference led naturally into a broader discussion about creative confidence. Early in his career, he admitted that he often attempted to solve design problems through increasingly complex layering and processing. Over time, he recognised a common trap. Designers frequently add more and more material when they become uncertain about their choices. One piece of advice from veteran sound designer Erik Aadahl remained particularly influential: the less confident you are, the more likely you are to throw the kitchen sink at a design. The observation is humorous, though it points towards a deeper truth about creative practice. Effective sound design is rarely an exercise in accumulation. It is an exercise in decision-making. Success depends less upon how many sounds can be added and more upon understanding which sounds genuinely belong.

    A story later in the lecture illustrated this principle perfectly. Working on a film involving a supernatural creature, Yocum spent weeks developing vocalisations based upon detailed descriptions provided by the filmmakers. Numerous versions were presented. None satisfied the directors. More versions followed. Still nothing. Eventually, after countless iterations and experiments, the sound that made it into the final film turned out to be a heavily processed recording of his French bulldog. The story generated laughter, though it also revealed something important about professional practice. Sound design is rarely a straightforward process of technical problem-solving. It often depends upon experimentation, intuition, collaboration, and a willingness to recognise successful ideas when they emerge from unexpected places. Behind the technology, the software, and the increasingly sophisticated production tools lies a creative discipline that remains deeply dependent upon listening, judgement, and imagination.

    Questions of attention remained central throughout the lecture, particularly when Yocum turned towards immersive audio formats such as Dolby Atmos. Discussions of Atmos often focus upon technology. Additional speakers create opportunities for sounds to move around an audience, above them, and through three-dimensional space. Yet one of the more interesting aspects of Yocum’s discussion was the extent to which he resisted treating the technology itself as the primary attraction. Additional channels do not automatically create better storytelling. A sound placed behind the audience is not effective simply because it appears behind them. It becomes effective when its position contributes to the emotional experience of the scene. This principle feels especially relevant to horror. Audiences are often more frightened by sounds they cannot see than by threats directly in front of them. A creak somewhere behind a listener immediately encourages questions. What caused it? How far away is it? Is it moving closer? A sound overhead may suggest a presence occupying unseen space. Rain surrounding a house can make isolation feel more tangible. In each case, the sound itself matters less than the uncertainty it creates. Atmos therefore becomes a storytelling tool rather than a technological showcase. The objective is not to demonstrate that sounds can move around a room. The objective is to shape how audiences imagine the world beyond the frame.

    Many of Yocum’s examples returned to this relationship between hearing and imagination. Horror repeatedly exploits the simple observation that listeners can hear far more than they can see. Sound extends perception beyond the limits of the image. A camera may reveal only a small portion of a location, though audio can suggest activity elsewhere. Something may be moving in another room. A distant voice may imply an unseen presence. A sound above a ceiling can transform an ordinary environment into a potentially threatening one. Once audiences begin constructing explanations for sounds that lack visible sources, imagination becomes an active participant in the storytelling process. Classic horror cinema frequently depends upon this principle. Yocum pointed to Alien as a particularly influential example. Although the creature has become one of the most recognisable monsters in film history, much of its effectiveness emerges from how rarely audiences see it clearly. Sound plays a crucial role in sustaining that uncertainty. The audience hears evidence of the creature’s presence long before receiving a complete visual understanding of what it is. Strange noises, movement within confined spaces, and subtle indications of activity allow imagination to fill gaps that images deliberately leave unresolved. The result is often more effective than direct revelation. Once a threat becomes fully visible, it also becomes more understandable. Horror frequently derives its strength from resisting that certainty.

    A similar logic appeared in Yocum’s discussion of possessed objects and haunted spaces. One example involved whispers gradually drawing a child towards a crack in a wall. Physically, very little is happening. The wall remains a wall. The room remains a room. Yet sound transforms the situation. The whispers encourage audiences to assign significance to something that would otherwise appear entirely ordinary. An inanimate object begins to feel charged with possibility. Attention becomes focused upon a location that images alone could never make equally compelling. Sound therefore contributes not only to atmosphere but also to narrative meaning. It guides audiences towards particular interpretations of what they are seeing.

    What emerged repeatedly throughout these examples was the importance of expectation. Horror does not simply frighten audiences through sudden surprises. It first teaches them how to anticipate those surprises. Once viewers recognise familiar patterns, filmmakers can begin manipulating them. Yocum highlighted Barbarian as a particularly interesting contemporary example. The film repeatedly establishes situations that appear to be moving towards conventional horror outcomes before abruptly changing direction. Audiences believe they understand what will happen next. The film then exploits that confidence. Sound design plays a central role in this process. Expectations must first be established before they can be disrupted. A soundtrack may encourage viewers to anticipate danger in one place while the real threat emerges somewhere else entirely.

    Taken together, these examples reveal a consistent philosophy running throughout Yocum’s lecture. Sound design is not simply concerned with what audiences hear. It is concerned with where they direct their attention, what they expect to happen next, and how they interpret incomplete information. Atmos, creature design, silence, environmental detail, and possessed objects may appear to involve very different techniques, though they frequently pursue the same objective. They encourage audiences to imagine worlds extending beyond what is immediately visible. Horror thrives within that gap between perception and certainty. The less certain audiences become about what lies beyond the frame, the more actively they participate in constructing the experience themselves.

    Looking back across the lecture, what emerges most clearly is a conception of sound design that extends far beyond the creation of individual sounds. Discussions of horror often focus upon monsters, jump scares, disturbing imagery, or technical effects, yet Yocum repeatedly returned to something more fundamental. Sound design is ultimately concerned with emotion. Every creative decision, from the selection of source material to the placement of a sound within an immersive environment, contributes to how audiences experience a story. This perspective helps explain why so many of the lecture’s examples appeared to revolve around expectation rather than spectacle. Silence becomes valuable not simply because it removes sound, but because it changes how listeners interpret what remains. Creature design succeeds not through complexity alone, but through an understanding of physiology, movement, and character. Atmos becomes meaningful when it directs attention towards spaces that audiences cannot see. Even the most effective jump scares depend less upon the scare itself than upon the tension that precedes it. Across each of these examples, sound functions as a way of shaping perception and guiding interpretation.

    Many of the stories shared throughout the lecture pointed towards the same conclusion. A restaurant toilet flush can become the foundation for a creature vocalisation. Weeks of carefully crafted designs may ultimately give way to a recording of a French bulldog. A whisper can transform an ordinary wall into something unsettling. None of these outcomes emerge from technology alone. They emerge from a creative process built upon listening, experimentation, and a willingness to follow ideas wherever they lead. The tools may continue to evolve, though the underlying challenge remains remarkably consistent: understanding how audiences will respond to what they hear. Perhaps this is why horror provides such a revealing lens through which to understand sound design more broadly. The genre exposes processes that are often present in other forms of storytelling but are easier to overlook. Audiences are constantly interpreting sounds, assigning meanings to them, and using them to make sense of the worlds unfolding around them. Horror simply makes those processes more visible. A creak in a floorboard, a distant movement, or a barely audible breath can suddenly become the focus of intense attention. The sounds themselves may be entirely ordinary. What changes is the emotional framework through which they are experienced.

    Returning to Yocum’s opening observation, the fastest way to make a horror film less frightening may indeed be to mute it. Doing so removes far more than sound effects or atmospheric detail. It removes anticipation. It removes uncertainty. It removes many of the subtle cues that encourage audiences to imagine what might happen next. Horror depends upon those moments of expectation, and sound plays a central role in creating them.

    A hallway. A footstep. A whisper from another room. A door slowly opening.

    None of these things are especially frightening on their own.

    Yet in the hands of a skilled sound designer, they can make an entire audience hold its breath.