5.1 Introduction

It wasn’t that long ago when our products only talked to us through sounds: beeps, alarms, bells, and squeaks. These days, Siri, Alexa, and other digital assistants talk to us in whatever language we choose on our computers and in our cars. We have come to depend on these auditory exchanges, just as we do with sight and touch, to enrich our sensory experiences. Design decisions can determine what things sound like, such as Siri’s voice or the microwave’s beeps.

We know that sounds engage people’s attention, whether as background in the environment or during specific product interactions. While you are reading this, what kind of sounds do you hear around you? Are some of those sounds closer to you and some farther away? These are all part of what is called the soundscape and many sounds that products emit are aimed to fit into the surrounding soundscape. However, many soundscapes are not harmonious: how many times has your focus been disturbed by an ambulance or fire truck siren? That persistently annoying and distinctive sound is very useful when emergency vehicles are weaving through traffic to answer an emergency call, but much less useful when it disturbs your quiet meditation practice at home! Have you ever been in a place where the ambient noise is so overwhelming that you can’t hear the person across from you? Many people have that experience when they visit busy restaurants, and as you may imagine, some of these sounds are unwanted. In design, we focus on sounds that are wanted, even if they are not always appreciated at the time – like a very loud alarm waking you up from a deep sleep.

Most people would agree that the sounds of nature, like a babbling brook or birdsongs, are more soothing to the ear than the sounds of highway traffic and road construction. On the other hand, you may have heard people who live near highways compare the constant noise to the ocean’s roar. This is a kind of biophilic response (Wilson, 1984; Kellert, 2018) in which we experience elements of our environments or objects as if they represent nature. However, many design elements do not provide for that biophilic response as designers prefer to incorporate intentional sounds into products that remind us of our prior sound associations and, therefore, leverage our abilities to interpret sound messages accurately. For example, designers generally do not design our toasters to croak like frogs when the toast is ready, or our keyboards to growl like angry bears when we hit a delete key, or our electric ovens to crackle like an open fire when we bake a cake. With these products, designers select sounds that are intentional, so that we hear our toasters “pop”, our keyboards “tap”, and our electric ovens “beep” when the cake is ready.

In this chapter, we will explore auditory experiences from three points of view: the properties of sounds, how people experience sound, and sound design. You will learn about:

• The properties of sounds that convey auditory information.
• The features of soundscapes that we interpret in meaningful ways.
• Applications for sound that are relevant to design.
• The emotional appeal of sounds.
• The categories of sound that correspond to different auditory messages.
• The process of sound design.