Architecture is often thought of as a purely visual form. After all, humans are widely thought of as visual creatures, interacting with a space first with our eyes.
But according to the emergent field of psychoacoustics, the sonic elements of a built space are as important to user experience as the more widely acknowledged aspects of the perceptible space.
A building’s sound can have a profound impact on the way that space is used, from questions of accessibility to hearing-impaired users to impacts on the way even neurotypical users with a full range of hearing interact with the space.
The sound of a built space has even been shown to affect the psychological and physical health of the people who use it — sometimes with surprisingly dramatic results.
“Psychoacoustics is really the psychological study of auditory perception,” said Dr Chris Plack, a professor of auditory neuroscience at Lancaster University in Lancashire, England. “What we’re interested in is the relationship between the physical sounds in the environment and your perceptions and your sensations that arise from that.”
A psychoacoustician considers the effects of the design choices made in the building process and how they affect the user experience of auditory effects such as loudness, echo and reverberation.
But as Dr Tim Ziemer, a postdoctoral researcher at the University of Bremen Spatial Cognition Center in Germany, points out, acoustics are often an afterthought in the design process.
“Unfortunately, many people are not consciously aware of most acoustical aspects of their environment until either an acoustician directs their attention to the acoustics or something goes horribly wrong,” Ziemer said. “This is true for those who commission, plan, build and, finally, use the built space. Acousticians are often consulted to rescue unbearable conditions of built spaces, instead of involving them at the planning phase.”
As Ziemer puts it, the acoustical design process originates from two different viewpoints. The first is purely practical; the second is a more artistic and affective approach.
“On the practical side, the acoustics of built spaces serve their specific purposes,” Ziemer said. “They support speech intelligibility in auditoriums; music enjoyment in concert venues; orientation at train stations; concentration in the office; relaxation in a park; comfort in a waiting room; proper communication of small groups in crowded function rooms; or privacy between adviser and customer.”
“On the artistic side,” Ziemer continued, “the acoustics of built spaces can be diversified, interesting, engaging and entertaining on a level between ambient and obtrusive. Artist and sound designers created soundwalks, soundscape compositions and sound sculptures, but these forms of art and entertainment are very rare.”
Physical and psychological impacts of sound
How do the acoustics of a space affect the people who use it?
According to Ziemer, the consequences of acoustic design can have a big impact on a person’s experience in a building or space. “Appropriate acoustical design makes you feel much more comfortable and safer,” Ziemer said, whereas badly designed acoustics cause immediately noticeable effects.
“Many people notice the negative effects of inappropriate acoustics in particular,” Ziemer said, including footstep or traffic noise, fragments of conversations travelling through open-plan offices and unintelligible announcements at airports and train stations. “Some buildings can even become an acoustical harassment for the people who live or work nearby,” Ziemer said, citing the case of Beetham Tower, which hums in high winds, causing sonic disruptions to both the users of the building and the surrounding community.
Plack cites classroom and office acoustics as particularly prone to design error. “When we take rooms, which are often quite large, and divide it up with partitions, you have all this background noise,” Plack said. “At the same time, all these hard surfaces cause a lot of reverberations and the sound bouncing around. This is a very hostile environment for someone with hearing loss, but also for people with normal hearing.”
Plack conducted a study showing poor acoustical design can lead to adverse information retention during lectures. “Even though people with normal hearing might understand the teacher, they have to expend a lot more effort to do so,” Plack said. “As a result, they get more fatigued and they have fewer resources for actually understanding the material.”
Designing an acoustically effective space
How can designers work to create an acoustically effective space?
For Plack, it starts with awareness. “Sound design often seems to be an afterthought with a lot of spaces,” Plack said, “but I think it’s a very important issue.” Consulting with audiologists at early stages of the design process can help architects conceptualise the ways that their design choices will affect the users’ sonic relationship with the space.
What’s more, taking the time to really consider your personal acoustic environment is a great place to start. “My advice is to attend a soundwalk,” Ziemer said. “This is an eye-opener (or rather, an ear-opener) for everybody, even for people with acoustical expertise. You are guided through an environment while listening to it, in different ways, with different tasks. There is so much to discover in our acoustical environment — our ‘soundscape.’ Once you’ve done that, you are certainly more open to acoustical design.”
Architect Gail Kennard agrees. “The impact of acoustics is very important in the design process,” Kennard said. “For the design of auditoriums, churches, libraries and other spaces used for performances, acoustics is critical. It impacts design elements such as where windows will or will not be placed.”
“For other places like hospitals, schools and childcare centres,” Kennard continued, “there is often a trade-off between the need for hard surfaces that can be cleaned easily vs. the need to buffer the greater sound that hard surfaces produce. Think the sound of shoe heels clicking on tile or vinyl flooring vs. carpets.”
Balancing effective sonic engagement with a space is an important part of making it user-friendly. And for designers interested in achieving this balance, psychoacoustics can be a vital piece of the puzzle.