More Than Just Noise

Anna Moldenhauer: Dr. Kusitzky, what does the city of the future sound like?

Thomas Kusitzky: Ideally, it should sound like what we imagine felicitous urban life would sound like. Future generations will have to decide for themselves what the specific sound of the city is to be. It's difficult to develop a universally valid “ideal sound” for the city of the future from our current perspective. Urban planning is full of grand visions that have turned out to be problematic in retrospect. It's therefore less about a master plan and more about negotiation processes that have to take place on the part of the people who live in cities and help develop them. What we can already analyse today, however, are existing problems, such as traffic noise, which we have to deal with, as well as aspects of sound that can already be considered positive.

What does your work look like in concrete terms?

Thomas Kusitzky: Initially, I approached looking at the sound of the city from an artistic point of view, but soon became active in research. About fifteen years ago, at the Berlin University of the Arts (UdK), I founded the Auditory Architecture Research Unit together with colleagues. At that time, several of our projects were funded by the Federal Office for Building and Regional Planning, and our main focus was on very fundamental questions: What aspects of design are we actually looking for when we talk about the sound of the city? What do we need to deal with in concrete terms? We came to the conclusion that the sound of the city should be considered primarily as a perceptual phenomenon. Based on this, we developed methods for capturing, representing and designing a city's sound as a perceptual phenomenon.

So it's a combination of research and practical application, supplemented by free artistic elaboration?

Thomas Kusitzky: My starting point was sound art in public spaces, but later my main focus became how to design the sound of everyday urban spaces in their entirety. The research projects I worked on were always practice-oriented, but despite this orientation I realised that a certain academic framework was necessary. For this reason I recently ventured a further step in the direction of practice: Since July of this year I've been working for the Berlin branch of the engineering firm Müller-BBM. The idea is to expand upon their existing technical-acoustic consulting services in urban land use planning by addressing the topic of urban sound design, in order to be able to consider as many influencing factors as possible.

Why has the field of auditory urban design seen so little development up to now?

Thomas Kusitzky: I can only speculate about this. There are already a great number of studies In the field of noise research, and many regulations as a result of this. These regulations are exclusively concerned with urban sound as a nuisance, however. This approach is rooted primarily in the 19th and early 20th centuries, when cities were perceived as becoming increasingly noisy as a result of ever more extensive industrialization and then electrification. The positive aspects of urban sound, on the other hand, continue to receive little attention today. In my opinion they are nevertheless extremely important for urban life and the experience one has in a city.

I certainly agree with you there! The technical side of sound is actively discussed, for instance in the planning of interiors, and also with a view to the well-being of people within the space. When we talk about architecture, on the other hand, the importance of sound is given little attention

Thomas Kusitzky: In architecture, when it comes to sound, the focus is usually only on function. This then involves optimised room acoustics for good speech intelligibility or for certain musical performances, for example. The goal is fixed from the outset and is to be achieved by technical means. Usually, there aren't any further considerations with regard to auditory qualities in the interior spaces. The situation is no better with regard to the external aural impact of the respective buildings: What sound is emitted or how building components reflect sound only plays a role, if at all at, with regard to noise protection regulations.

How do you make a room come alive, sound-wise?

Thomas Kusitzky: Within buildings, sound propagation can be controlled by the size and shape of a room, and by the kind of surfaces it has. This is what makes classic room acoustics. For example, if the surfaces of a room reflect sound strongly, it will seem larger – but a cooler atmosphere may also be created. In addition, it's important to keep an eye on what and when sound is entering from outside the room. So what can I expect to have in the individual rooms, and what's a suitable use for a particular room? And the use of the rooms themselves naturally has an effect on the sound experience as well. After all, this is where most of the sound comes from. In the case of urban space, the situation is quite different since many different sound-relevant activities take place in parallel and need to be included in the planning. The decisive factor here is the organisation of the spaces themselves. Sometimes it even makes sense to create attractive areas where people are inclined to spend more time. Their activities then become audible.

Can you give me an example?

Thomas Kusitzky: At the UdK we had a major research project for Berlin's listed Ernst Reuter Platz. The approximately 180-square-metre plaza consists of a multi-lane roundabout, a large central island, and several large side areas outside the roundabout that are mostly unused. Surrounding the plaza are several office buildings, and the joint campus of the UdK and the Technical University is located in the immediate vicinity. As a result, there are always quite a few people on the move on weekdays. Interestingly, however, they are almost inaudible. Instead, you almost exclusively hear road traffic, even if it's not that loud, at least in the large side areas. The fact that the many people can hardly be heard is mainly due to the fact that they only cross the plaza, but don't spend any time there. Ths means that hardly any conversations can be heard and other activities that could be audible don't take place. The central island is also rarely used, as there's little incentive to spend time there. Of course, it would help to slow the traffic down a bit and thereby reduce it acoustically, but this wouldn't make any other activities audible, since they don't take place anyway. The plaza would likely remain the inanimate and barren place it now is. One solution would therefore be to create incentives for people to spend time there. This could be, for example, a skating rink in the winter or a basketball court during the summer. Of course, something like a café or restaurant would also be conceivable, something that brings some life to the plaza and counteracts the monotony of the traffic.

So it's important to think about human dynamics in urban planning and to avoid a homogeneity of sounds?

Thomas Kusitzky: If you could establis some other activities at this plaza, the traffic noise would no longer be in the foreground. However, since each place has its own conditions, and it also depends on what you want to establish there, I wouldn't say that a heterogeneity of sounds is basically good.

So one place's sound concept is not necessarily transferable to another. In your research have you been able to find out whether the quality of a public space is perceived as higher when people hear themselves, for instance their own footsteps?

Thomas Kusitzky: This is indeed the case. We haven't conducted any scientific studies on this, but there is definitely empirical knowledge in this regard. Especially in Berlin, you often hardly notice yourself on the large, multi-lane streets. You don't hear your own footsteps, you don't hear the way your clothes rustle when you move. On some streets, you also have to talk very loudly in order to be understood at all. I would say self-awareness is a quality to strive for in most places. It's true that there are places where it's just a matter of blending in with the crowd, like at markets. But in many situations it's unpleasant if you aren't aware of yourself because you're virtually swamped by the sounds surrounding you.

Are there any materials that you'd like to avoid using in architecture, from a sound perspective?

Thomas Kusitzky: That really depends on the overall context. Glass, for example, which is very highly sound-reflective, is not fundamentally a bad material. However, you have to be aware of what it does, and then you can use the effect in a targeted way. The big problem with the many glass facades in the city is that there is still a lot of automobile traffic, the noise from which is amplified by reflections on smooth walls. Visually, glass facades are usually talked about as being transparent. From a purely acoustic point of view, however, they are the opposite, as they allow very little sound to pass through. If you are able to open a window, that definitely has a tonal quality as well: You then have the opportunity to connect with the outside space, making it a form of participation.

Are there sounds that you specifically look for in a city?

Thomas Kusitzky: It depends on the situation I'm in and what I want at that particular moment. In my opinion, there's no such thing as the “ideal” urban sound. Cities should instead offer diversity for their residents: Access to quiet places as well as to those that allow participation in public life. To be connected to the community, but to still have privacy. In one of my projects, a resident I interviewed once said she wanted to hear her neighbours without wanting to understand them. I think some kind of phasing would be desirable. For example, if suburban residential areas don't have any diversity, they become inanimate during the day, which leads to an insane acoustic void for people who don't go to work in the morning. You're then no longer part of the community.

Diverse sound situations thus also have an impact on social behaviour, on a feeling of togetherness. At the same time, silence is often praised as a valuable commodity when searching for a place to live, and paid for accordingly. What do you think about this?

Thomas Kusitzky: This ideal of silence that's been promulgated again and again in recent years is an interesting point, for example in some guides on noise protection. I would say that it's the wrong direction, however. When there's a noise problem, the knee-jerk reaction is often to remove as many sounds as possible. But instead I would say that if you define noise as unwanted sound, then in most cases the solution is not to have no sound, but instead desirable sound.

How the city sound is perceived is very individual. How can you design a city that is perceived as pleasant by the cross-section of residents?

Thomas Kusitzky: To a certain degree, I would take issue with the assumption that the perception of sound is only subjective. Of course each person hears for themself and each has an individual sound experience. But the most important thing for the auditory experience is one's own hearing biography, and there's a huge overlap here. We share many listening experiences with our fellow human beings, especially when it comes to the same cultural area. We grew up in the same places, were confronted to a large extent with the same sounds and had similar experiences with them. The experiencing of sound is therefore individual, because each person hears for themself. But at the same time it's also intersubjective, because your momentary experience is based on common experiences. Using this common foundation, it's then possible to design. It's possible to say with a certain degree of confidence what the goal is and what's to be avoided, even if it isn't possible for the respective overall sound to please everyone all the time. In the end, this isn't any different than in the visual field of architecture.

There are many points of view in the discussion about the sound of mobility in the city – automobile engines are becoming quieter in the course of electric mobility, but at the same time, sounds are needed for orientation and safety in road traffic. A lot of experimentation with sound design in concept cars is happening right now. Where would you position yourself on this?

Thomas Kusitzky: Many hopes for less traffic noise are associated with electromobility, as the motors are hardly audible. At speeds of more than 35 km/h, however, tyre noise is much more relevant. Electric cars are also no longer seen as really helping to create quieter cities, since they have to emit artificial noises at speeds below 20 km/h in order to avoid accidents. In terms of the quality of the city's sound, I would therefore instead advocate a more comprehensive change in overall traffic patterns, away from private cars. Space previously used for streets could also be rededicated, allowing the resulting environment to be tonally enriched by new uses.

Partly, sounds are produced at local transport stops to create a pleasant atmosphere. How far would you say it is justifiable to want to influence the mood of people in cities through sound?

Thomas Kusitzky: As soon as this is done in a manipulative way, it's to be rejected, as far as I'm concerned. There's a device called The Mosquito, for example. It produces a very loud, high-pitched buzzing at over 17,000 hertz. This is now being used to drive young people away from selected places. With age, hearing in the upper frequency range diminishes, and therefore the noise only disturbs a certain age group. I'm also very sceptical about music in public space, because whether the music presented appeals to me depends very much on my personal taste and, of course, on my mood at the moment. Finding something that works for everyone all the time is probably a hopeless undertaking.