One very interesting trend the last couple of years has been the advances in hi-fi audio cues in interaction designs. As speakers are becoming smaller, better, and cheaper, we suddenly find ourselves in an immense milieu of sounds and audio cues. In this articles I’ll highlight the invisible details of audio design, and hopefully make you think about how best to integrate the effects of audio cues in your next interaction design.

TEDtalk: Julian Treasure: The 4 ways sound affects us

Sounds influence us on a very deep level. They can calm us – or stress us. Sounds influence our mood, and as such they are very powerful tools when designing interfaces.

When Sound is Designed

Tweetbot by TapBots has a completely bespoke interface. It’s part of their brand and one of the primary drivers of their fame. But they also have a bespoke sound-scape. They’ve included subtle, and some not so subtle, audio cues to polish the experience and delight their users. It’s a marriage that works great – and Tweetbot is actually one of my favorite apps because of this.

BMW, Mercedes, and Bang & Olufson are renowned for their work on audio design. When closing a CD-player on a B&O stereo it has a very distinct sound. Like Goldilocks the sound must not be too loud, or clunky, or plastic-y – it has to be just right. When you slam a door shot in a Mercedes it should sound like closing a heavy-duty safe – secure, purposeful, built to last. The sound may have nothing to do with the actual materials used. Yet, the audio designers must create sound, which hints the user of the implied quality of the product they operate. It’s part art and part science.

Learn from Hollywood

Hollywood is the land of stories and storytellers. As interface designers we can learn a lot from them. Foley artists and sound editors have produced immersive and convincing audio backdrops for decades. Using associative sounds in your interface, you get a whole new palette of brushes to enhance and develop your interface from.

Take the iconic sound of a roaring V8 and how it perfectly epitomizes the dream of the fast car. Hollywood has taught us for generations that’s how a fast car sounds. The sound of the roaring motor is so engrained in our cultural understanding of the performance car, it’s quite a challenge to design a performance sound for the EV era (never mind slamming luxury doors).

Audi knew this when they built their electronic version of their super car, the R8 e-tron. EVs really don’t produce much natural sound except for a bit of wind and tire noise. Gas powered vehicles all produce a familiar sound of Vrrom due to the combustion, tubes of exhaust pipes, and matrix of moving cogs and pistons. Electronic Vehicles don’t have such luxuries when it comes to natural sound production. The engine in an EV has very few sound-producing parts other than an electric drivetrain, which only produces a flat hiss – not quite the contestant to the mighty V8. Faced with this challenge Audi had to design an exhilarating quality ‘operational’ sound for the car.

Audi R8 e-tron sound design

Yet, sounds not only work to enhance the experience, but can also work as a safety measure. Pedestrians and cyclists orient themselves to the surrounding cars by the sound a car makes. But if cars make no significant or recognizable sound, we have a potentially dangerous situation. Audi designed an engine sound for their e-tron that not only alerts pedestrians but also evokes emotions of power and acceleration. It’s not a digital recording of a combustion engine mascaraing the car as gas-guzzling V8, but the team instead looked towards Hollywood and recreated the iconic warping sound of cars in the future.

Using sounds in Interaction Design you can access a part of the brain that is very hard to reach using visual sensory. Sounds feed directly into our emotional system and often directly to the subcortical part of our brain, and thus bypass the filtering function of our cortex. You can test it on yourself; next time you watch a horror movie, try to mute it in one of the scary scenes, and see what happens. Not nearly as scary, right? Sound and music are subliminal – it operates on a much lower level than visual sensory. When designing interfaces you can exploit this fact and design sounds to enhance the experience, guide actions, and motivate the object-manipulation – without bringing attention to the actual sound. It’s like a fabric you can wrap your whole interaction in to achieve different effects.

Quick Tips for Sound Design

Design for the context. Is the sound to be used in a car or a cellphone? The speaker and the surrounding ambient noises are very different from a car and a cellphone. Find sounds that suit the speaker type and interaction mode. Work with the constraints.

Be subtle. Just like anti-aliased text rendering works wonders on fonts for screen display, subtle sounds can truly enhance the emotional experience of the product. Practice the Goldilocks principle; the sounds mustn’t be so pervasive that you continually notice them, but on the other hand can’t be so low that you hardly notice them at all.

Don’t be corny. Strike a balance of recognizable and original. Associative sounds are powerful tools to be used lightly. The sound of a traditional phone ringing is VERY constrained in its uses because it’s soiled in cultural associations. Even the more subtle sounds, like the keyboard click-sounds on the iPhone and iPad virtual keyboard, can be very distracting. In my opinion the iPhone’s keyboard clicks are way too suggestive of an actual physical keyboard, which it’s obviously not. The iOS keyboard clicks are the audio equivalent of the Corinthian Leather stitches.

Learn from Hollywood. Be a storyteller. Exploit the fact that Hollywood has trained the world for generations in how everything from cars to robots sound. Use it and build upon it.

Experiment. Sound is a very dynamic medium. Our environments and technology, as well as our expectations to our devices and interfaces, change all the time. Experiment with the Doppler Effect or noise-cancelling algorithms. Surprise and delight.

DDB Stockholm’s “Fun Theory” campaign for Volkswagen.

Next time you design an interface, whether mobile, desktop, physical, or something entirely different, consider the implications of sounds. Integrate sound design from the ground up. Research sound-scapes, like you’d research color palettes. Experiment and try to build a specific navigation with the primary interaction mode guided by sounds instead of visual cues. The future is bright and sounds great.

Inspiration and further reading:

Designing With Audio: What Is Sound Good For?
Neuroscience and Music (PDF)
Andrew Spitz Sound Design 

Feature image CC Vancouver Film School