Bright Lights, Quieter Cities?

A Techwise Conversation with acoustic engineer Nick Antonio

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Hi, this is Steven Cherry for IEEE Spectrum’s “Techwise Conversations.”

Probably ever since humankind learned to control fire, people have organized themselves into settlements, villages, towns, and eventually cities. But in 2007, the world reached a tipping point: For the first time in history, a majority of the world’s population now lives in urban environments. There are now 20 megacities—that is, 10 million inhabitants or more—with two more by 2015. By the 2030s, 5 billion people will live in cities. That’s a lot of people—and a lot of noise.

There’s a bunch of defining characteristics of cities—art, theater, skyscrapers, museums, finance, fine dining, and, of course, bright lights—but one of them has to be noise. From the garbage trucks grinding their way through the predawn hours to the horns of the taxi drivers creating their own traffic jams late at night, with rattling jackhammers and screeching subways, with trucks and buses, sidewalk vendors and street musicians, it all adds up to a lot of noise.

Tourists seem to welcome it; it’s part of the what they travel hundreds of miles to experience. But for residents, it’s just one more thing we have to put up with. Or do we? Are there things cities can do to make themselves less noisy?

My guest today, Nick Antonio, is an acoustics engineer with Arup. He joins us by phone from Los Angeles, but Arup is a global firm of designers, planners, and engineers. Its projects range from Paris’s Pompidou Centre and the Sydney Opera House to New York’s Second Avenue subway and the 2008 Olympics in Beijing.

Nick, welcome to the podcast.

Nick Antonio: Hi, Steven. It’s good to join you.

Steven Cherry: Nick, did I overdo it in my intro? How big a problem is noise?

Nick Antonio: For me, it’s huge. This is my life, if you will. Noise is very much treated as a Cinderella pollutant, in my eyes. Obviously it’s got very low or negligible energy savings if you reduce noise, and it’s ephemeral and invisible and ubiquitous, but it’s huge and it’s everywhere, if you will.

Steven Cherry: Yeah, a Wall Street Journal article recently called it “secondhand smoke for our ears.” What about regulations? Are they too weak or just not enforced? Are they effective at all?

Nick Antonio: That’s a really big question. Around the world, it varies, obviously, between different countries. Here in the States, we have various noise regulations which are really quite simplified. But when it comes down to sound isolation, for instance, between apartments, the performances that we’ve got here are really not very good at all. We’ve got some of the lowest standards of the developed world here in the States. In Europe, it’s much better. In Northern Europe the standards are excellent, and as you tend to move south through Europe, they tend to be slightly more relaxed.

Steven Cherry: Well, I guess everywhere, better technologies will help. Let’s start with transportation. That seems to be something a lot of cities come to your company for. I guess there’s a big difference whether we’re talking about an individual truck or a subway car or designing an entire highway or subway line. Maybe just walk us through all that, no pun intended.

Nick Antonio: Yeah, I mean clearly there’s a number of different noise issues that you would look at in designing transportation sources themselves. Obviously there’s the people who are in the transportation themselves, so there’s the design of acoustics within railcars and reducing the noise that people are exposed to. But the big issue with most transportation sources, of course, is the impact that the transportation source has on the surrounding environment, and that really varies. I mean, people respond differently to different transportation sources, interestingly enough. So, for instance, people really don’t like the sound of helicopters, but for a given noise level, the same number of decibels, people are more accepting of a fixed-wing aircraft. And people like trains more than they like cars, and they like cars more than they like aircraft. So people react differently to different transportation sources for the same level of sound.

Steven Cherry: So what do you do as a designer to make people’s experience better?

Nick Antonio: There’s a number of different aspects. I mean, quite closely tied in with the sound itself is the source of the sound, so there are all sorts of psychoacoustic approaches to these things, and different senses merge, if you will. A really interesting experiment carried out some years ago was where a professor, Hugo Fasti, took a very controlled acoustic environment and played the noise from a train at a fixed level to a bunch of students and put a picture of a red train on the wall. It was just a stationary train. And he asked the students to rate the noise level of the train, so they marked this thing. And then he put exactly the same noise level into the same space and played it to a bunch of students again and put a green train on the wall. And the guys that saw the green train rated it as quieter than the guys that saw the red train, even though the noise level was exactly the same. So this basically tells us that we don’t just look at each sense in isolation, but we have other factors, as well, which affect the way that we perceive the world.

Steven Cherry: So other than painting cities entirely green, what can you do?

Nick Antonio: From a mechanistic point of view, there’s a whole series of things, of course. We can put barriers in. We can put screening in. We can deal with noise at source. So road traffic is the main pollutant in most cities, and dealing with that at source is in tire design, in low-noise road design, the road surface itself. Clearly if we can change the speed of cars, then we can reduce the noise of them as well, and then we start moving into barriers. And if we’ve got the ability to work at a larger scale than cities, then we could put in barrier blocks and move roads effectively away from sensitive areas. So we can start looking at holistically designing spaces so we can have quieter areas and noisier areas.

Steven Cherry: So those highway barriers really make a big difference…

Nick Antonio: Oh, absolutely. Yeah, absolutely. There’s a lot of work that’s gone into highway barriers. I mean, the big thing, of course, is height with the barrier, but we’ve also looked at different types of barriers so that they are acoustically absorbtive, so there’s less reflection from them. And also some really interesting work is happening at the moment in terms of barrier shape—the tops of barriers—because clearly a barrier, sometimes it’s fixed in terms of its height, and people have been looking at different ways to scatter sound going over the top or diffract sound going over the top of barriers, so that a lower barrier can have the same performance as a higher barrier, but its just got an unusual shaped top to it.

Steven Cherry: And what about the vehicles themselves, and in the case of us subway commuters, the subway cars themselves?

Nick Antonio: We normally try and reduce sound within subway cars, and that’s really in the design of the vehicles, the sound isolation of the vehicle, and reducing vibration within the space itself. For motorcars, we’re really on the cusp of something very very exciting at the moment in terms of the step change that we’ve got for electric vehicles. For the last hundred years, we’ve had internal combustion engines, and it’s really quite difficult to significantly reduce the noise from an internal combustion engine. But moving to an electric motor, they are really significantly quieter.

Steven Cherry: I’m interested in talking a little bit more about the economics of your profession. It seems to me this might be one of the big problems for you—that putting barriers on highways don’t improve the number of cars that the highway can carry. You pointed out at the top that working on noise doesn’t improve the efficiency of anything. It seems to me, you know, in New York, at least, our experience is that restaurants don’t spend a single dime making it easier for people to hear one another.

Nick Antonio: Restaurants are a really interesting case in point from an acoustic perspective, because we have drivers within restaurants, where the users of a restaurant would really like to have the space quieter and more peaceful, if you like, so they can talk to their colleagues and their friends and whoever they’re having a meal with. From a restaurant user’s point of view, and perhaps this is just me being cynical about this, they have an incentive in many restaurants to actually have people eat their food and not linger and talk and carry on within the space. So there are incentives in restaurants and in clubs, of course, to decrease the amount of communication that we have in there. And it’s sort of evolutionary, I feel, where some restaurants are quiet and subdued and you can sit and talk to your friends. But many of them, they just want to get people in, feed them the food, get the bill, and then move on, if you like.

Steven Cherry: Yeah, I think restaurateurs want their places to seem more lively and energetic, and they like it to be noisy.

Nick Antonio: Absolutely. And that’s another perhaps less-cynical view of the way that people actually experience restaurants and why they go to them as well.

Steven Cherry: You mentioned apartment buildings earlier, and it’s a well-known fact here in New York that older apartment buildings—the so-called prewar buildings—are much quieter than newer ones. The walls are thicker, I guess, or at least more absorbent of sound. But here, again, it seems like nobody’s willing to sink whatever it costs to make apartments quieter.

Nick Antonio: I disagree with that slightly. I think there’s a range of people who will develop things. And again, we need to be careful about which countries we’re looking at this in, because code varies quite considerably around the world. In some parts of the world—Germany and some of the Nordic countries—code is really quite high, to the point where when we design high-end residential buildings here in the States, we’re effectively reproducing those sorts of standards. I mentioned at the top of this program that code is really quite low here in the States, and at the bottom end of things, it’s a point where certainly many people might be expected to easily hear their neighbors and probably be upset with their neighbors.

The only other thing is that we have the ability to be able to demonstrate aural environments much more clearly now. There’s a breaking technology, so the SoundLab is a space where we can use it to either demonstrate the acoustics of a space accurately, and it’s really quite magical from an acoustic perspective. Being able to play an unbuilt space accurately to somebody, to say, “This is what you’re going to get” or “This is the effect of design changes in that space.” And we can do that both from a room-acoustic point of view, so internally within spaces, and we use it traditionally for concert halls and auditoria and theaters and things like this, but we also use it as well for environmental noise. So environmentally we can play people the sound of trains into an existing environment. And it becomes a very powerful tool, because we’re not saying to somebody, “We think that you won’t have a problem with it.” What we’re saying is, “This is what you’re going to get, and you can now make your own mind up in an accurate informed-decision sort of way.” And it means that we don’t need to resort to numbers, which are probably meaningless to most people, and also we avoid the semantic comparisons. So we’re not saying, “It would be as loud as a city street or as quiet as a bedroom at night” or something. We can actually accurately play people a sound in a controlled environment and allow them to make their own minds up.

Steven Cherry: And ideally it would actually be the architects who design spaces who would be making their minds up. Is this the sort of tool that an architect could actually use?

Nick Antonio: Oh, totally. Absolutely. Yeah, yeah. We use it a lot with architects, also with the end users, because there’s a real incentive for an end user to be able get buy-in, and it’s a great opportunity to be able to know early on in the design if somebody has a problem with something, and it gives somebody the confidence as well that we’re going in the right direction from an end-user point of view. The better that we have buy-in and understanding, the better the design will go toward the end of it.

Steven Cherry: So how does this work? Is it all in software, or do you have to actually build something physically?

Nick Antonio: The Arup SoundLab is basically—we have a number of these around the world—but it’s an ambisonic space. The room itself is relatively low tech, if really quite clever, in terms of its being quiet and acoustically controlled. But the really clever side of things—and I think this is where you’re coming from, if you like—lies in the processing power that’s now available to us to auralize spaces. It’s effectively a sphere of sound. So we have the ability to be able to accurately play back sound not in mono or stereo, or even in 5 or 7 or 13.1, or whatever, but in a 3-D way. So the sound is coming accurately in phase and in level and in frequency to the people that are actually listening to this, so that we could actually show somebody, demonstrate the exact environment within a space.

Steven Cherry: One last question: It seems to me that we’ve had acoustic engineers for the better part of a century now, and yet overall I’m not sure that the world hasn’t just gotten more noisy. What’s your projection for the future? Is noise going to keep winning, or will the acoustic engineers finally get the upper hand?

Nick Antonio: We talked a little bit before about quieter vehicles, and that’s going to make a huge difference to the global environment. But I feel that the real driver is going to be probably at a high governmental level in terms of legislation and control. We already see this in Europe, with the Environmental Noise Directive, and looking at the way that that’s controlling noise in Europe. We don’t have a parallel for that here in the States, so it’s going to be patchy, and I think that noise is generally going to reduce, driven from the highest levels and with some new technologies.

Steven Cherry: Well, very good. Well, Nick, the population of the planet continues to rise, and cities are the most efficient way for humans to live, so we’d better make them as habitable as possible, and that’s where people like you come in. So on behalf of all of us city dwellers, good luck to you, and thanks for joining us.

Nick Antonio: Thanks, Steven.

For IEEE Spectrum’s “Techwise Conversations,” I’m Steven Cherry.

Announcer: “Techwise Conversations” is sponsored by National Instruments.

This interview was recorded 3 April 2012.
Segment producer: Barbara Finkelstein; audio engineer: Francesco Ferorelli

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