Hear Here!

Artwork provided by  Jon McCormack .

Artwork provided by Jon McCormack.

This episode was written and produced by Fran Board.

Humans have been fascinated with acoustics since our earliest ancestors. From Roman amphitheaters to modern symphony halls, we’ve designed our spaces with sound in mind. But the relationship between acousticians and architects isn’t always smooth sailing. In this episode, we explore the way acoustics has shaped our history and what we might do to make our spaces sound better today. Featuring Emily Thompson, author of The Soundscape of Modernity and Professor of History at Princeton University, and Trevor Cox, author of Sonic Wonderland and Professor of Acoustic Engineering at the University of Salford.


Oh My My (Instrumental) by Summer Kennedy
Going Forward Looking Back by Sound of Picture
Bambi by Sound of Picture
Gears Spinning by Sound of Picture
Tweedlebugs by Sound of Picture
Algorithms by Sound of Picture
Trundle by Sound of Picture
Delta by Sound of Picture
Massive Attack by Sound of Picture
Lone Road by Sound of Picture
Flutterbee by Sound of Picture

Twenty Thousand Hertz is produced out of the studios of Defacto Sound, and hosted by Dallas Taylor.

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View Transcript ▶︎

[SFX: Inchindown sax]

You're listening to Twenty Thousand Hertz. I'm Dallas Taylor.

[SFX: Inchindown sax up]

Believe it or not, this is the sound of one, single, saxophone. The angelic sound is created by the space around the saxophone. This recording was done in an old oil depot called Inchindown. It’s an underground complex of huge oil tanks in Scotland. Some of these tanks are forty feet high and double the length of a football field. But the coolest thing about them is they hold the record for the longest reverberation time of any man-made structure.

[SFX: Inchindown sax crossfades with the music track]

[music in]

Acoustics is the study that deals with how sound works in a space. It’s something we don’t usually think about, but it actually plays a huge role in our lives.

Here’s the good news... You’re already an acoustics pro! Humans are great at listening for clues about our surroundings. That’s how you already know that I’m speaking to you from a recording studio. You’d notice right away if I were somewhere else, like in a bathroom [SFX reverb] or a cathedral [SFX reverb]. See? You already inherently know all about acoustics.

And while we don’t usually come across acoustics quite as spectacular as this oil depot, they play a big part in our lives wherever we are.

[music out]

We’ve only just begun to really understand acoustics in the last hundred years. But our fascination with it goes back thousands of years.

[music in]

Trevor: If you go into a cave or you go into a stone circle, the acoustics would have been unusual to our prehistoric ancestors. It would be really surprising if you didn't go in there and enjoy the acoustics. After all, if a toddler goes into a railway tunnel, they all start yelping because it sounds exciting.

That’s Trevor Cox. Trevor’s a Professor of Acoustic Engineering at the University of Salford. He’s also the saxophonist you heard at the start of the episode.

Trevor: There's this theory around that where cave paintings are found is where the acoustics are good.

Researchers found that cave paintings of animals like horses and bison are usually found in more reverberant spaces. If the most interesting acoustics were in a narrow tunnel that was difficult to paint in, our ancestors would sometimes just draw red marks on the wall instead. It’s as if they were highlighting the interesting sounds.

[music out]

The theory is that these places were used for ceremonies and storytelling. We all know how much more interesting voices sound when they’re echoing off the walls. These reverberations could even turn the sound of hoofed feet [SFX] into a herd of galloping horses [SFX]. Our ancestors might not have understood the science of acoustics, but it sure seems like they were fascinated by them.

[music in]

Man-made structures have been built with acoustics in mind since the earliest human civilizations.

Emily: People have been considering how sound behaves in space really for as long as we have records, at least within Western civilization. You can go back to Ancient Greece and Rome, and writings indicate that people were considering these problems.

That’s Emily Thompson. She’s a professor of history at Princeton University. Her studies focus on sound technologies in American culture.

Emily: It's important to understand that, back in the time of Ancient Greece and Rome, architecture, science, music, were all considered a kind of part of the same holistic intellectual entity. They weren't considered distinct or separate in the way we perceive them today.

Many of these ancient civilizations believed that everything was tied together by harmonic ratios.

Emily: This connected the movement of the planets to principles of design for architecture, as well as the harmonies of music, and all of nature was really understood to be tied together by perfect ratios.

Emily: And so, that was one way to connect sound and space: To design spaces that embodied the kinds of harmonic ratios that were seen as the foundation of music.

[music out]

One of the best examples of man-made acoustics from this era is the amphitheater. These spaces hosted gruesome gladiator battles and chariot races [SFX], as well as theater and music. The largest amphitheaters could hold about fifteen thousand spectators. Architects designed these spaces to filter out background noise so everyone could hear what was going on. And considering there was no electricity for amplification, it’s a pretty remarkable feat for an ancient civilization if you think about it.

And just like today, a lot of old spaces were designed with music in mind. But other times, composers crafted their music around the space instead. It’s actually had a significant impact on our music history.

Trevor: If you look at Western music, going back to, sort of, 16th, 17th century, it's all about what was happening in churches really, in terms of Western classical music.

Trevor: There's no point, for example, going to a grand cathedral and writing something with lots of very fast moving music and words that are rapidly delivered, ‘cause everything would have been a mush and unintelligible

Trevor: That's the reason you have things like plainsong. It's a kind of way of getting words across which is more intelligible in a very reverberant environment.

[SFX: Plainsong]

In the 16th Century, churches started being built with balconies inside of them. That sounds like a small detail… but even small changes can alter acoustics drastically.

Trevor: The acoustics tend to get a bit drier, less reverberant. That then influences music. Because you can write more intricate music. There's people who argue that Bach's music, some of his very fast moving pieces would never have been written if church acoustics had never changed.

[SFX: Bach’s B Minor Mass]

Some people think that this seemingly tiny detail is actually one of the most important factors in the history of music. And it was all thanks to acoustics.

[music in]

Our understanding of acoustics evolved dramatically in the late 1800’s. Harvard University had just constructed a new museum. But they soon discovered one of its lecture halls was completely unusable due to the acoustics. The room was huge, with semi-circular walls and a domed ceiling. Because of this, students couldn’t tell at all what the professor was saying... So, the university’s president turned to a young physics lecturer, Wallace Sabine, to try and fix the room’s sound problem.

Emily: The president probably thought that he would just do a little bit of research, figure out why the music hall at Harvard sounded pretty good, and then apply that knowledge to this new room which didn't sound good.

But it wasn’t quite that easy.

Emily: Sabine was a kind of consummate, perhaps even obsessive, experimenter, and he took this small query and actually spent three years working late at night, when the campus was quiet, painstakingly taking measurements of the sound of spaces all over campus.

One time, Sabine threw out thousands of measurements after he realised that his clothes were having a tiny effect on his results. To most of us it might not have mattered. But for Sabine, this was a big deal. He started all over again, and from that point on he always wore the same outfit.

[music out]

Sabine would move huge amounts of soft surfaces into a room, like cushions and rugs. Then, he’d measure how it changed the sound of the room. He didn’t have any fancy technology to do this - just an organ pipe and a stopwatch.

[music in]

Emily: Sabine pored over his data, the data that he had been collecting painstakingly in notebooks for years and years, and he finally discovered a mathematical relationship between all these data points, that would ultimately provide a kind of a key to connecting the different materials that make up an architectural space with the reverberant or echoey quality of that space.

He figured out that the time it takes for sound to fade away is based on the size of the room and the amount of absorbent material in it. It may sound obvious to us now, but this breakthrough is the cornerstone of all of modern-day acoustics.

[music out]

Right away, Sabine’s formula was changing the way buildings sounded.

Emily: This became a very powerful design tool that offered the authority of scientific understanding, but at the same time it didn't force the architect's hand. It allowed you to choose what kind of materials you wanted to use, and by doing so proportionally, you could create any kind of reverberant quality you wanted.

Around that time, the Boston Symphony Hall was being built and an acoustics expert was needed.

Emily: The idea was to create a temple for this musical sound.

So they hired Sabine to advise them on how to make the hall sound just the way they wanted.

Trevor: It actually made a great concert hall, which is still revered as one of the great concert halls in the world today.

There’s even a plaque dedicated to Sabine in the lobby of Symphony Hall. It commemorates the building as the first auditorium in the world to be built according to his specifications and formula.

Here’s what Symphony Hall sounds like. This is the Boston Symphony Orchestra performing Shostakovich’s Presto from Symphony number 6.

[SFX: Symphony Hall, Boston]

[music in]

Trevor: If you look at a modern concert hall and look at what Sabine was working with, it's like comparing a Model T Ford with a modern car. A lot of the basics are very similar but there's a lot and lot of development.

Modern day materials can help spread the sound more evenly across an entire symphony hall. This gives the audience a more equally enjoyable listening experience no matter where they are seated.

Emily: They developed a way to create a tile that had a porous surface, and those pores would absorb sound energy.

These tiles let architects design spaces that sounded completely different from how they looked. You could make a big Gothic cathedral sound more like a small, intimate space.

Emily: It was clear that the way a room looked was no longer inherently connected to the way it would sound, in the sense that had always characterized the sound of architecture, for centuries really.

Acoustic materials, like special plaster and flooring, are used in all types of modern buildings to control acoustics.

[music out]

Nowadays, modern concert halls can even change their sound on demand. This is great for music fans, since it means one space can be used for all sorts of different performaces.

Trevor: Often, if it's a venue where there's a very famous orchestra, the primary purpose will be designed to make it to work for the classical orchestra. [SFX: Classical music] But, then if you go and bring along a rock band [SFX: Rock music], you'll find it sounds awful, a soupy sound, doesn't work with electronic reinforcement with loud speakers. What you typically do is you bring in an absorbents, you bring in material, fluffy stuff that deadens the acoustic.

While we understand acoustics pretty well, there still isn’t one mathematical formula for creating the perfect concert hall. Sometimes, it’s just down to personal preference.

Trevor: There isn't a definitive ideal design for a concert hall.

Trevor: There are people who like to listen to lots of reverberation, so they like to have a swimming sound, a little bit like being in a cathedral. But, there's the other people who prefer a clear sound, a bit more like listening to a CD.

[music in]

Concert halls today look and sound amazing. Thanks to Wallace Sabine, we can enjoy Beethoven symphonies, Chopin nocturnes, or even modern rock music in a space tailored perfectly for it. But even though we’ve come a long way, good acoustic design is still slipping through the cracks. And this oversight might just be jeopardising our future. We’ll find out how, after the break.

[music out]


[music in]

A lot of thought goes into the acoustics of modern concert halls and theaters. So you’d think that other important buildings would sound good too, right? Well… not exactly.

Let’s think about some buildings where sound really matters. For me, schools and hospitals are near the top of the list… Maybe offices and transit stations too.

[SFX: train station]

Unfortunately, these places are well known for having lousy acoustics.

[music out]

Trevor: The design of everyday spaces tends to get overlooked, but it's incredibly important.

If a concert hall sounds terrible, people will notice. Designers know that it’s important that they sound just right. But acoustics in schools and offices have been a massive problem for decades and few people have spoken up.

Trevor: I think the problem with architecture is it's taught very much as a visual art. So, if you go to an architect school, you'll see lots of pictures up, you submit your folder of visual images about the building you're making, or you might get a walk through, nowadays, in a VR suite, but it probably won't have any sound on it.

Trevor: So, they're taught to think about circulation, light and visual, but they're not really taught so much to deal with the acoustic. It's obviously a bit harder to get your head around, because it's not something you can print on a page.

As a result, the architecture-acoustics relationship is pretty murky.

Trevor: Bexley Business Academy is a really good example of what happens if architects and acousticians don't work together to make it a success.

[music in]

Bexley Business Academy was built in London in the early 2000’s. It was designed by award-winning architects. The British Prime Minister opened the building and it was even short-listed for a prestigious architectural award. But amazingly, the architects had designed the classrooms with no back walls.

Trevor: So you can imagine a sort of a big office block, where you have a central atrium, and off to the sides, you have what would normally be the offices, but in this case were the classrooms.

This was an open-plan school?

Trevor: And the added stupidity was they put design and technology at the ground floor. So there were people using machines down on the ground floor, the noise would come up through the atrium and leak into the classrooms. [SFX: machinery noise] You can imagine how amazingly distracting and how difficult it is to teach in such an environment.

They had to spend tons of money sorting out the acoustics.

Trevor: To give you a sense, I think it was nearly a million dollars worth of remedial work to put walls back in.

Trevor: It shows you how much money you can waste if you don't get the acoustics right the first time.

[music Out]

Thankfully, there aren’t too many classrooms without back walls. But bad acoustics are a big problem in traditional classrooms as well. Modern design trends are a big part of the problem. Hard shiny surfaces like glass and polished wood may look nice, but they bounce sound around the room like crazy. Even older school buildings can be a problem, with high ceilings and hard floors.

The most obvious problem with this sort of design is that it’s hard to hear the teacher. But that’s just the tip of the iceberg.

[SFX: classroom babble]

Trevor played the sound of this classroom chatter to a group of teenagers while they were taking a test. He wanted to find out how it affects their performance, it lowered their cognitive ability by three years. Study after study shows that noise is terrible for learning.

It can cause stress, hearing loss, bad behavior, high blood pressure, and more… and these aren’t just abstract theories. They’re happening right now.

The good news is you don’t have to be an engineer or a physicist to improve the acoustics around you. Things like carpets and cushions can make a real difference. And it’s certainly worth giving it a try. Scientists have tested whether better acoustics would improve classrooms. In one case, kids’ grades improved, and in another, teacher illness plummeted by thirteen percent.

The key is creating a more thoughtful relationship between architecture and acoustics.

Trevor: One of the problems we have in architectural acoustics is the people like me, the acousticians, the experts, are engineers. We work with charts and graphs and we really understand it. The architect comes from a completely different background and probably has very little or no acoustic training.

[music in]

Fortunately, there’s a modern breakthrough that could solve this problem. It’s called Auralization. It lets architects actually hear what a building will sound like before it’s built. Imagine how that might have helped that open-plan school...

Trevor: We're all listeners. That can be the start of a conversation to say okay, if you design it this way, it's not going to sound good and rather than say this number is wrong, we can say, listen to it. Can you hear that effect?

Listening gives architects and acousticians a common language, which is something we clearly need.

Emily: Architectural acoustics matters because the ways we experience and engage with our sonic environment really tie us very physically and materially to that place where we are, as human bodies.

We’ve been fascinated with acoustics since our earliest ancestors made paintings in caves. Today, we have the knowledge to design beautiful sounding spaces that make our lives better. It’s a testament to the amazing things human ingenuity is capable of. And we can use that ingenuity everywhere, not just in concert halls and theaters. We’re all experts in acoustics, so it’s important we get them right.

[music out]

[music in]

Twenty-Thousand Hertz is produced out of the studios of Defacto Sound, a sound design team dedicated to making television, film, and games sound incredible. Find out more at defactosound.com.

This episode was written and produced by Fran Board, and me, Dallas Taylor, with help from Sam Schneble. It was sound edited by Soren Begin. It was sound designed and mixed by Jai Berger.

Thanks to Trevor Cox of Salford University and Emily Thompson for speaking with us. If you’d like to find out more about acoustic technology and its effect on culture, check out Emily’s book, “The Soundscape of Modernity.”

Thanks also to Danielle Marcum York for naming this episode. If you’d like to help name future episodes, or want to tell us what you think is the best sounding concert hall, write us on facebook or twitter, you can also email us at hi@20k.org.

Thanks for listening.

[music out]

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