Sound Design at Edinburgh Napier University

Category: Products

  • How Do You Give a Monster a Voice? Matthew Collings on Performance, DSP, and Creature Sound Design

    Matthew Collings

    Every audience knows what a dinosaur sounds like. Dragons roar, aliens snarl and giant monsters shake cinemas with impossibly deep voices. Yet none of these creatures has ever existed. Every sound associated with them has been created from scratch, yet audiences instinctively accept them as real. Creating that illusion is one of the most fascinating challenges in sound design.

    This was the starting point for Matthew Collings’ guest lecture on creature vocalisation and real-time sound design. As an audio programmer at Crotos, the company behind Dehumanizer, Collings explored how advances in digital signal processing are changing the way creature voices are created. The lecture, however, was about much more than a single piece of software. It invited the audience to consider a broader question: how can technology extend creative expression without diminishing the artistic judgement that remains central to sound design?

    Creating convincing creature voices has traditionally been one of the most demanding areas of audio production. Designers layer recordings of animals, manipulate pitch, combine multiple processing techniques and painstakingly synchronise every vocalisation with an animated character. The results can be extraordinary, but they depend upon considerable time, technical expertise and countless creative decisions made after the original recording has taken place.

    To illustrate this established approach, Collings showed a video in which legendary sound designer Ben Burtt described the creation of Chewbacca’s voice for Star Wars. Rather than relying on a single animal recording, Burtt assembled the character’s voice from bears and numerous other animals, selecting each recording because it conveyed a particular emotional quality. Some sounds suggested affection, others frustration, aggression or excitement. Through careful editing and synchronisation, these individual elements became the distinctive voice of a character that had never existed. The example serves as a reminder that audiences respond to emotion and personality as much as acoustic realism.

    Collings argued that this creative principle remains unchanged, even as production workflows evolve. Traditionally, creature voices were assembled through careful editing once recording had finished. Increasingly, however, designers can manipulate voices in real time, hearing the transformed result immediately as they work. Instead of constructing every roar, growl or vocal gesture afterwards, they can shape those sounds during the act of performance itself. Digital signal processing therefore becomes more than a post-production tool. It becomes an expressive instrument, allowing sound design to move beyond editing and towards live creative interaction.

    That shift has implications far beyond creature effects. It changes the relationship between performer, sound designer and technology, bringing them together within a single creative process. The remainder of the lecture explored how real-time processing makes this possible, why it offers advantages over traditional workflows, and what this evolution might mean for the future of sound design in film, games and immersive media.

    If real-time processing changes the way creature voices are produced, what actually makes this approach different from traditional sound design? At first glance, the technology itself seems familiar. Pitch shifting, convolution, granular processing and modulation have all been part of the sound designer’s toolkit for many years. As Collings demonstrated, the real innovation is not the individual processes but the way they can be combined and controlled during a live performance. Instead of waiting until recording has finished, designers can hear the transformed voice immediately and respond to it in the moment.

    This represents a significant departure from established workflows. Traditionally, creature vocalisations have been built through accumulation. Designers layer recordings of animals, manipulate pitch, combine multiple processing techniques and synchronise every sound with an animated performance. The results can be extraordinarily rich and expressive, but they are achieved through careful editing and refinement after the original recording has taken place. Every decision is made retrospectively.

    Collings demonstrated an alternative way of working. Rather than treating the recorded voice as material to be reconstructed later, the performer hears the transformed character immediately while responding to the animation. Every breath, hesitation and change in vocal expression influences the processed sound as it happens. Recording, listening and refinement become part of a continuous creative cycle rather than a sequence of separate production stages.

    Watching this process unfold was particularly revealing. It felt less like observing a conventional editing session and more like watching a musician perform with an unfamiliar instrument. The software undoubtedly transformed the incoming voice, but the character emerged through timing, expression and continual adjustment. Technology extended the performer rather than replacing them.

    The individual processing techniques shown during the lecture each contributed something different to the final result. Pitch shifting altered the apparent scale and physical presence of a creature. Granular processing introduced texture and unpredictability, while convolution blended characteristics borrowed from recordings of the natural world. None of these techniques was presented as a complete solution. Instead, convincing creature voices emerged through the interaction of multiple subtle transformations, all shaped by a responsive vocal performance and careful listening.

    This also explains why recordings from the natural world remain so important. Animal vocalisations contain acoustic qualities that listeners instinctively recognise, even when heavily transformed. Rather than imitating individual species directly, designers borrow elements from familiar sounds and reshape them into voices that feel plausible despite belonging to imaginary creatures. The result is neither entirely natural nor entirely artificial. It occupies a convincing space somewhere between the two.

    Perhaps the most striking aspect of the demonstration was how quickly the technology faded into the background. Audiences do not hear convolution, granular synthesis or pitch shifting. They hear a creature reacting to its environment. For the practitioner, the individual processing modules matter far less than the expressive possibilities they create. The objective is not to showcase sophisticated digital signal processing, but to shape a voice that feels authentic within the fictional world it inhabits.

    By reframing digital signal processing as a creative instrument rather than simply a collection of effects, Collings presented real-time sound design as more than a technical improvement. It represents a different way of thinking about the craft itself, where listening, experimentation and creative judgement become increasingly intertwined with the act of performance.

    The implications of this approach extend well beyond creature vocalisation. Although Collings’ demonstrations centred on monsters and dinosaurs, the underlying principles apply wherever sound must respond dynamically to performance. Film, games and immersive media increasingly require audio that can evolve alongside the action rather than being fixed during post-production. As production workflows become more interactive, sound design is beginning to shift from constructing sounds after the event towards shaping them as creative decisions unfold.

    This evolution also changes the relationship between performer and sound designer. Traditionally, these roles have been separated. An actor delivers a vocal performance, while the sound designer interprets and transforms it later through editing and processing. In Collings’ demonstrations, however, those boundaries became less distinct. The transformed voice could be heard immediately, allowing every vocal gesture to influence the next. Performer, practitioner and software formed part of a continuous dialogue in which listening, adjustment and expression happened simultaneously.

    Watching this process unfold felt surprisingly different from observing a conventional recording session. Rather than painstakingly constructing every vocalisation afterwards, Collings responded to the animation as it played, continually refining the sound in real time. The software functioned as an expressive instrument, yet the musicality came from the person using it. Timing, pacing and emotional intent remained far more influential than any individual processing technique.

    Perhaps the most revealing aspect of the lecture was its emphasis on listening. Numerous processing techniques were demonstrated, but none was presented as a formula for creating convincing creature voices. Instead, expressive results emerged through continual refinement, balancing multiple transformations until the voice felt appropriate for the character and the scene. The demonstrations reinforced a familiar truth within sound design: technical knowledge provides possibilities, but careful listening determines which possibilities are worth pursuing.

    This way of working also encourages a more exploratory creative process. Because ideas can be evaluated immediately, designers are free to experiment with subtle variations in delivery, processing and timing without committing to lengthy post-production workflows. Some ideas will inevitably be discarded, but others may reveal unexpected qualities that would have been difficult to discover through a more linear editing process. Real-time processing therefore supports experimentation not by making creative decisions easier, but by making them easier to explore.

    Looking beyond creature vocalisation, Collings’ demonstrations suggest a broader evolution in the practice of sound design. As digital signal processing becomes increasingly responsive, practitioners are no longer confined to refining performances after recording has ended. They can participate in the creative act itself, shaping sound as it develops while drawing upon the same critical listening, imagination and editorial judgement that have always defined exceptional work. The tools may be changing, but the craft remains firmly rooted in human perception and creative decision-making.

    Although Dehumanizer provided the focus for the demonstrations, the lecture ultimately explored a much broader evolution in sound design practice. Throughout the session, Collings showed that the most effective technology is rarely the most conspicuous. Whether refining a creature’s vocalisation, combining different processing techniques or responding to an animated sequence in real time, the objective remained the same: to create voices that audiences accepted instinctively as part of a believable world.

    One consequence of this approach is that experimentation becomes far more immediate. Presets provide useful starting points, while more advanced controls allow practitioners to shape every aspect of the resulting sound. Instead of investing time constructing complex processing chains before hearing the outcome, designers can move quickly between ideas, evaluating and refining them as they work. The software therefore accelerates exploration without diminishing the value of experience or technical understanding.

    The lecture also reinforced an enduring lesson about creature vocalisation itself. Convincing voices rarely emerge from a single recording or a single processing technique. They develop through the careful interaction of vocal performance, recordings from the natural world, digital signal processing and critical listening. Each contributes something different, but none is sufficient on its own. The illusion succeeds because these elements are brought together in support of character, emotion and storytelling.

    Taken together, Collings’ demonstrations point towards a broader change in the discipline. As real-time processing becomes increasingly sophisticated, the traditional boundaries between recording, editing and performance begin to blur. Sound designers are no longer limited to refining material after a recording session has ended. Increasingly, they are able to shape expressive performances as they unfold, responding directly to performers, animation and narrative in the moment.

    This does not redefine the purpose of sound design, but it does reshape the role of the practitioner. The craft continues to depend upon careful listening, imagination and aesthetic judgement. What is changing is the point at which those skills are applied. Rather than waiting until production has finished, they become part of the performance itself.

    That is perhaps the lecture’s most enduring contribution. Rather than presenting another collection of digital effects, Collings demonstrated how real-time processing is reshaping the practice of sound design while leaving its creative foundations unchanged. If the opening question was how imaginary creatures can sound so believable, the answer lay not in software alone, but in giving sound designers increasingly expressive ways to listen, respond and shape performances as they unfold.

  • 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.

  • 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.