How do robots communicate through sound?
People increasingly interact with technology through sound. Smartphones acknowledge completed payments, electric vehicles alert drivers to potential hazards, wearable devices provide subtle notifications and intelligent products communicate through a growing vocabulary of tones, chimes and alerts. Yet these sounds rarely receive the same attention as visual design. During his online guest lecture for Edinburgh Napier University, Connor Moore explored the growing discipline of Audio User Experience (Audio UX), demonstrating how carefully designed sounds help products communicate naturally, build trust and express personality. Drawing upon projects for companies including Google, Tesla and Postmates, he argued that successful product sound design extends far beyond creating attractive audio. It begins with understanding the people for whom they are designed. Throughout the session, one principle emerged repeatedly. Every sound should communicate with purpose.
Moore introduced his work by describing the remarkable breadth of modern Audio UX. Working from California’s Bay Area, he collaborates with companies developing products across robotics, automotive technology, connected devices, consumer electronics and digital services. Although these industries appear very different, they all share a common challenge. Products increasingly communicate with people through sound, requiring designers to think carefully about what those sounds communicate and how they contribute to the wider identity of a brand. Rather than approaching each project as an isolated collection of sound effects, Moore described building coherent sonic systems that extend across products, marketing, physical environments and user interactions. Individual sounds matter, though they become most effective when they form part of a larger and recognisable design language.
This broader perspective also explains why strategy sits at the beginning of every project rather than at the end. Before designing a single sound, his team seeks to understand the objectives of the product, the identity of the organisation and the experience that users should ultimately have. Brand workshops, creative discussions and detailed reviews of existing sounds all contribute towards this early stage of development. Competitor analysis also plays an important role. Understanding how other companies sound allows designers to identify opportunities for meaningful differentiation rather than unintentionally reproducing familiar ideas. The objective is not simply to sound different. It is to create a sonic identity that genuinely reflects the values and personality of the organisation. Sound therefore becomes a strategic design material rather than a decorative addition introduced once the product has already been completed.
One of the most thought-provoking ideas introduced during the presentation concerned what Moore described as connected audio ecosystems. Many organisations continue to commission isolated sounds for individual products or services, yet users increasingly encounter the same company across multiple devices and environments. A person may hear a notification on a smartphone, interact with a smart speaker at home, use an in-car navigation system and later encounter advertising or public installations produced by the same organisation. Rather than allowing each experience to develop independently, Moore argued that they should all share recognisable sonic characteristics. Consistent instrumentation, similar timbral qualities and carefully related musical ideas allow users to recognise a brand without needing to see a logo or screen. Sound therefore becomes another component of brand identity, working alongside visual design to create familiarity and trust.
Google’s product ecosystem provided one of the clearest illustrations of this philosophy. Moore described how his work began during the development of Google Glass, a product that sought to make an unfamiliar technology feel approachable. Rather than emphasising futuristic electronic sounds, the design drew upon simple acoustic instruments such as piano, chimes and mallet percussion. These familiar timbres helped ground an otherwise unfamiliar experience, making the product feel more human and intuitive. As Google’s product portfolio expanded through devices such as Pixel phones, Google Pay and automotive systems, this underlying sonic character evolved while remaining recognisably connected. Different products naturally demanded different technical solutions and frequency ranges, though the overall identity remained remarkably consistent. Moore argued that brands evolve in much the same way as people do. Their sonic identities should therefore develop over time while retaining a recognisable sense of continuity.
Perhaps the most unexpected principle discussed during the session concerned silence. Designers often assume that every interaction requires another notification, another confirmation or another layer of feedback. Moore challenged this instinct directly. As products increasingly incorporate sound into everyday life, designers also acquire a responsibility not to make the world unnecessarily louder. Like negative space in graphic design, silence performs an important communicative function. It creates contrast, draws attention to genuinely important events and prevents users from becoming overwhelmed by constant auditory stimulation. Successful Audio UX therefore depends not only upon knowing which sounds should exist, but equally upon recognising which moments deserve silence instead.
He illustrated this philosophy through the development of Sense, a sleep monitoring device designed to help users understand the quality of their sleep. Conventional alarm clocks often rely upon abrupt, attention-grabbing sounds that force people awake almost instantly. Moore saw an opportunity to rethink that experience entirely. Instead of beginning loudly, the alarms gradually evolved over time, introducing increasing musical complexity, richer timbres and subtle changes in tempo. Lighter sleepers could wake during the earliest stages, while heavier sleepers would gradually encounter a more energetic composition. Even error tones and voice interactions were designed using soft, restrained timbres that preserved the calm atmosphere of the bedroom rather than disrupting it. The project demonstrated that product sounds need not simply communicate efficiently. They can also influence the emotional quality of everyday experiences.
Moore then introduced one of his central design philosophies: communicative and expressive design. Throughout the presentation, he repeatedly distinguished between creating sounds that merely reinforce a brand and creating sounds that genuinely help people understand what is happening. Branding undoubtedly matters, though communication always takes priority. Every sound should first convey meaning. Only then should it contribute towards a wider sonic identity. This perspective encourages designers to think carefully about urgency, expectation and human perception rather than treating every notification as another opportunity for creative expression. Product sounds exist to guide behaviour as much as they exist to establish identity.
Tesla provided a particularly revealing case study. Moore described developing different categories of sounds according to the urgency of the information they needed to convey. Low-priority events, such as incoming calls, were designed to emerge gradually using softer timbres and lower levels of perceptual urgency. Medium-priority notifications, including seatbelt reminders, employed greater repetition and brighter timbres, encouraging users to respond without becoming unnecessarily stressful. High-priority warnings, including forward collision alerts, demanded a very different approach. Higher frequency content, more percussive attacks and rapid repetition ensured that these sounds immediately captured attention during situations where rapid action could prevent an accident. Rather than relying upon arbitrary aesthetic decisions, Moore demonstrated how pitch, repetition, harmonic content and timbre can all be manipulated systematically to communicate different levels of urgency. Sound becomes a carefully designed language through which products communicate urgency, intention and behaviour.
By this stage, a clear philosophy had emerged. Audio UX is not simply concerned with creating pleasant sounds or memorable sonic logos. It asks how products should communicate with the people who use them every day. Strategy, branding, silence, musical structure and perceptual psychology all contribute towards that objective, though none of them represents the ultimate goal. Every design decision serves the relationship between people and technology. Once sound is understood as a form of communication rather than decoration, the challenge shifts from asking what a product should sound like to asking what it should say. That question became even more significant when Moore turned to the rapidly developing world of robotics.
The second half of Moore’s presentation shifted from broad design principles towards a detailed case study that demonstrated how those ideas are applied in practice. The project centred on Serve, the autonomous delivery robot developed by Postmates. Rather than treating the robot simply as another product requiring notification sounds, Moore used it to explore a far broader question. How should an intelligent machine communicate with people as it moves through shared public spaces? The answer, he suggested, depends upon much more than selecting attractive sounds. It requires understanding personality, context, expectation and human behaviour long before the first sound is ever designed.
Like every project discussed earlier in the presentation, the design process began with strategy rather than sound. Before any recording or composition took place, the team explored what the robot represented, how people would encounter it and the personality it should express. Several distinct sonic directions were developed around different interpretations of the brand before being refined through successive design reviews and evaluated within the robot itself. Moore emphasised that successful Audio UX develops through continual iteration rather than moments of inspiration. Sounds that appear convincing inside a studio may behave very differently once reproduced by a moving robot navigating busy streets, restaurants and crowded pavements. Testing therefore becomes an integral part of the creative process rather than simply a means of checking technical performance.
One of the most revealing aspects of the project concerned personality. Popular culture has encouraged audiences to expect robots to communicate through futuristic electronic sounds or highly expressive synthetic voices. Moore deliberately avoided both extremes. The ambition was to create a robot that felt warm, approachable and reassuring without pretending to possess human intelligence or emotional awareness. At the same time, the team resisted the temptation to rely upon recorded speech, recognising that a natural voice would create expectations that the technology could not consistently fulfil. Instead, they searched for a middle ground in which sound suggested character without imitating humanity. This balance between familiarity and honesty reflected one of the most thoughtful ideas running throughout the presentation. Good Audio UX should communicate clearly without misleading users about a product’s capabilities.
Developing that personality required exploration rather than immediate certainty. Moore described creating several contrasting sonic directions, each expressing a different interpretation of the robot’s identity. Some embraced more mechanical qualities that acknowledged the machine’s physical presence. Others explored vocal-like synthesis capable of suggesting expression without becoming literal speech. A third direction employed simple sine-wave tones that created a calmer, softer and more abstract character. Rather than choosing a favourite instinctively, these alternatives became prototypes through which designers could observe how people responded emotionally to different sonic identities. The final design combined warmth, clarity and subtle expressiveness, producing a robot that felt approachable without becoming theatrical or sentimental. The process illustrated an important principle: successful sound design rarely emerges fully formed. It develops through comparison, evaluation and refinement.
Attention then shifted from the robot’s overall personality to the design of individual interactions. Different situations demanded different styles of communication. Interactions inside restaurants, where staff loaded deliveries into the robot, prioritised efficiency through short, direct auditory cues that confirmed actions without interrupting the workflow. Encounters with members of the public required a gentler approach. Longer note durations, more relaxed phrasing and softer musical gestures created the impression of patience rather than urgency. In effect, the robot adapted its acoustic behaviour according to the social environment in which it operated, much as people instinctively alter their own behaviour between professional and public settings.
A particularly memorable example centred on one of the simplest interactions imaginable: saying, “Excuse me.” Rather than relying upon recorded speech, Moore developed a brief auditory gesture that politely attracted attention before allowing the robot to continue its journey. The intention was not to surprise pedestrians or demand an immediate response. Instead, the sound functioned more like a courteous acknowledgement of another person’s presence. This small interaction captured a principle that extended throughout the presentation. Effective communication often depends upon restraint rather than intensity. Products should seek attention only when attention genuinely needs to be given.
Safety presented a different set of priorities. Warning sounds must communicate immediately and unambiguously, leaving little room for ambiguity or interpretation. Here, Moore returned to ideas introduced earlier in the presentation. Instead of inventing unfamiliar sonic languages, the design frequently drew upon acoustic references that people already understood from everyday experience. Turn indicators, movement cues and other operational sounds retained familiar characteristics while remaining consistent with the robot’s wider sonic identity. This reduced the need for users to learn entirely new sonic conventions. Familiar sounds could be interpreted almost instinctively, allowing people to respond appropriately without consciously analysing what they had heard.
Perhaps the most technically demanding challenge involved the robot’s continuous movement through public space. Moore explored several possible solutions, including humming, whistling and slowly evolving tonal textures that he described as “glowing.” Each communicated the robot’s presence in a slightly different way. Some attracted attention more effectively, while others blended more comfortably into the surrounding soundscape. Extensive user testing, including sessions involving blind participants, revealed that restrained harmonic complexity and carefully controlled modulation proved more effective than more elaborate alternatives. Yet Moore resisted the temptation to increase the amount of sound simply to improve awareness. His longer-term ambition was quite the opposite. Intelligent products should become quieter rather than louder. If a robot recognises that nobody is nearby, there may be no need for it to produce sound at all.
This idea provides a fitting conclusion to Moore’s broader philosophy of Audio UX. The discipline is not concerned with filling products with attractive sounds or memorable sonic logos. It asks how technology can communicate clearly, respectfully and appropriately with the people who use it. Whether designing for autonomous robots, electric vehicles, smartphones or medical devices, the same principles continue to apply. Strategy comes before implementation. Communication matters more than novelty. Personality should remain authentic. Silence deserves to be designed as carefully as sound itself. When those ideas come together successfully, sound ceases to be decoration and becomes an essential part of the conversation between people and technology.