The Infinite Monkey Cage - The Science of Sound

Episode Date: December 12, 2011

Robin Ince and Brian Cox head north for the second time this series, and take residence for one episode in the BBC Philharmonic's headquarters to talk about the science of sound. They are joined by the University of Salford's acoustic expert Professor Trevor Cox, neuroscientist Professor Chris Plack and comedian and former acoustics student Tom Wrigglesworth to talk about all things noise related. With some musical accompaniment, they'll be discussing why some sounds sound nice and some sound horrible. Why certain sounds are noise and others are literally music to our ears, and whether specific sounds can trigger specific emotions. But perhaps the biggest question of all is, are there any clues in the chord sequences to D:Ream's hit "Things can only get better" that made it the perfect soundscape for to a political leadership campaign?..maybe that's something that even science can't answer!Producer: Alexandra Feachem Presenters: Robin Ince and Brian Cox.

In our new podcast, Nature Answers, rural stories from a changing planet, we are traveling with you to Uganda and Ghana to meet the people on the front lines of climate change. We will share stories of how they are thriving using lessons learned from nature. And good news, it is working. Learn more by listening to Nature Answers wherever you get your podcasts. This is the first radio ad you can smell. The new Cinnabon pull-apart only at Wendy's. It's ooey, gooey and just five bucks for the small coffee all day long.

Taxes extra at participating Wendy's until May 5th. Terms and conditions apply. This is a download from the BBC. To find out more, visit bbc.co.uk slash radio4. Hello, this is the Infinite Monkey Cage and he is Brian Cox. His favourite law is the

second law of thermodynamics. I would go so far as to say that it makes him hot but clearly it doesn't or at least not for very long. And here's Robin Ince, and his very big law was Hooke's law until he found out it only applies below the elastic limit. Why only below the elastic limit? Yet again, Wikipedia, with its information, ruins my life.

Today we are looking at the physics of sound. As we're discussing sound, we've come to the home of the BBC Philharmonic here in Salford. Sadly, though... We couldn't afford the whole BBC Philharmonic because I frittered the entire BBC science budget away on volcano-resistant shoes and Gore-Tex. If only you hadn't used the helicopter to get here. I was so looking forward to having a violinist.

So we had a wit round, and we got just one! So, please welcome this week's special guest, violinist Julian Gregory. For regular listeners who might not know, we always have a regular violinist, because they haven't heard it. We do always have a regular violinist, but they normally get cut out from being rubbish. Julian, this is a no-pressure situation.

Violin for us. MUSIC Jaunty. I like my science jaunty. MUSIC That's enough, that's enough. Don't overdo it. In today's show, we'll be seeking scientific answers to questions such as, what is the most terrifying noise to human ears? And what are the probable evolutionary reasons that we find these sounds disconcerting?

Sounds such as... Yeah, it's going to be an amazing science show. Why would we find the sound of a drill that we normally think of as going into our teeth and creating agony, why would we find that disconcerting? We'll be giving you scientific reasons. And why do certain sounds just make us miserable? Yes, we're in Salford, so we are playing there.

Aren't cockneys miserable, unlike you lovely northerners? Card. So what is the science of sound? To help us find out, we're joined by a panel of experts and a comedian because we think comedy helps the average listener comprehend the complex nature of the natural world. Yes, for instance, I only understood the ramifications of the relativistic nature of time when I went to see Ken Dodd.

3am before the first interval. 3am! Joining us today is Trevor Cox, who is a professor in acoustic engineering. His special interest is the perfect design of rooms for intelligible speech and music, which is why he's banned from Radio 1. Professor Chris Plack holds the Ellis Lewitt Jones Chair in Audiology at Manchester University,

and he's published over 50 articles in peer-reviewed journals, including The Effects of Low and High Frequency Suppressors on Psychophysical Estimates of Basilar Membrane Compression and Gain. Popular one. I've got to laugh. Available in all good bookshops. And Off-Frequency Growth of Masking of masker duration in forward masking. Further evidence for the influence of the peripheral non-linearity, as if further evidence was required.

You're right there, Brian. I think we've got enough, haven't we, on the peripheral non-linearity nowadays. Finally, Tom Rigglesworth is a comedian and winner of So You Think You're Funny competition in Edinburgh. He was also nominated for the Edinburgh Comedy Award and has also won a Sony, but today he's returned to his old stomping ground, the Acoustic Department of Salford University, that should be made clear that do not stomp in the Acoustic Department. It may affect the results of some of the experiments. And this is our panel. Trevor, we're in this room which has been specifically designed

for classical music, the home of the BBC Philharmonic. Is the design of concert halls, would you say, a science? Is it an art? Is it architecture? Is it some kind of mixture of the three? It's probably a mixture, but I think in this room there's more science in here than probably art, because this is... LAUGHTER

Maybe I should rephrase that. Even when the orchestra is playing. In the design of the hall, there's probably more science than art because it's specifically designed for recording in. So we're not trying to create a great architectural space for audiences normally. So as you look around this room, you'll see perspex bent shapes above us, reflectors there, specifically there to give reflections

down to the orchestra so they can hit themselves we have all these strange slatted things around the walls which are all specifically angled to give reflections to help the orchestra hear each other so there's a lot of design work gone into making this sound exactly right and that is a science now why is it um we went off on tour a while back and found that concert halls were not good for spoken word quite often. A couple of concert halls we play, particularly if Dara O'Brien talks very quickly

about poorly thought-out research into neutrinos in Hollywood movies while swearing, going, ah, there's pesky neutrinos. If he does that very fast, it appears... In a New York accent. Oh, those pesky neutrinos. Of course, because he's doing the voice from the film, you idiot. So we found that some people in certain corners of the concert hall, in between us. Of course, because he's doing the voice from the film, you idiot. So we found that some people in

certain corners of the concert hall, for the spoken word it was very difficult to pick up all of the swearing. Most concert halls which are used for classical music are designed first to work for the orchestra. So they design it to have this big reverberance. But that's not very good for speech. That actually gets in the way of intelligibility.

It makes the words run into each other. most halls most intelligent halls have got designs in there they've got stuff fluffy stuff they bring out literally sort of curtains and all sorts of stuff to try and dampen the space down for when they have electronic stuff when they have speech but there are halls where that isn't done very well and yeah it's a it's an unintelligible mush see i like there was one concert we played the seats had been specially made to absorb sound, forgetting, of course, that hopefully there will be people sitting in the seats that are sitting on the sound absorber. Oh, that's quite deliberate,

because an orchestra will rehearse in an empty concert hall, and they don't want the concert hall to be very different when they come and play the concert. I mean, if you go and rehearse in a space with wooden chairs, like a church, it will sound completely different when the congregation come in and fill up all the pews. So they try and make the acoustic roughly the same, empty, occupied, half full, whatever it is.

It's got to be roughly the same. So if you had an audience that looked like most people were quite bony, should you then try and compensate by asking for some people who'd let themselves go a bit as well to try and absorb the sound? There was a very good paper from Australia years ago which looked at the effects of clothing on absorption so they had the audience in various levels of undressed down to swimming trunks to see what effect it had on the absorption and we're going to repeat that experiment this evening

now tom tom you did a degree in acoustics here at Salford. So what does that entail? I mean, is it mathematics, is it a mixture of physics, is it a mixture of engineering? Well, I'm going back... You don't remember, do you? 12 or 13 years, yeah, there's been a lot of time and alcohol between then and now. And I must state as well that I did study under Professor Trevor Cox here,

so anything I say which is wrong... LAUGHTER ..it's not strictly my fault. LAUGHTER But it's basically incredibly hard mathematics. That's my memory of acoustics. It's really, really hard maths. And it's good, because I think that's why music is appealing, really, to me, because artistically, of course, it's very creative,

but it's sort of underpinned by this very solid groundwork of physics and hard maths. And I'm really fascinated by that, the joining of the two, which is why these rooms are really interesting, because I know it looks awful, but it sounds so alive. And you can create great art in here, but it's all underpinned by this real bedrock of hard maths. So do you think that means people enjoy, you know, as a mathematician,

you go, well, of course, I enjoy Beethoven a lot more because I understand it mathematically, whereas those people who can't do the sums will never enjoy this. You get musical snobby, though, don't you? You get jazz and jazz is even harder, like harmonically and mathematically, to unpick than X Factor, for example. So, yes, I think musical snobs would argue

that they understand it more, therefore enjoy it more. The same way that people might like fine wine, as opposed to Vimto. I mean, Sam, we're going to come back, actually, to the mathematical underpinnings of music. Let me ask Chris first. We're talking about sound in this room, and I suppose to a physicist, sound is very simple to define.

It's just a pressure wave going through air. But is there more to it, or is that it? How would you define sound? Well, I think there are two definitions, really. You can either define it in a physical way, which is just pressure variation. It doesn't need to be any medium at all. Or you can define it as sound is something that we hear. And that goes to the essential question, you know,

if a tree falls in a forest for no one there to hear it. That's philosophy. It's banned. We don't do philosophy. Well, no, no, no. It's a new definition. If a tree falls in a forest, no one there to hear it, then according to the physical definition, yeah, there's a sound, because you still get pressure variations, but in terms of the psychological definition, then no, there wouldn't be a sound because there was no-one there to hear it.

So it's got to have a receiver to validate the definition. Yeah, but the interesting thing is when you have sounds which aren't actually in the physical world, but you hear them, and one example of that is, I don't know if anybody here has tinnitus where you have some ringing in your ear if you listen to lots of people are nodding out there I get it a bit if you've listened to a lot of loud music in your life you can often damage the ear a little bit and that can create these sort of phantom sounds and there's no sort of physical pressure variations going on but people still say they hear a sound.

I do find it very weird when you say the thing about when a tree falls. The sound does occur, just because we didn't experience doesn't mean that there aren't two separate arguments. But I was talking to you beforehand, come on here, where when I'm on a plane at high altitudes, I seem to be able to hear music very specifically as if it's actually in my ears. And this may well be a cry for help. And I wonder if there is something which is changing my perceptions.

It's not with my ears popping or anything like that. I can actually be sitting there with no headphones in or anything like that, and I can hear very clear music, and it's kind of not just ideas that I'm picking out from the air around me. It's specific songs. Now, is there a way that a brain changes the way it perceives sound or the way that it can itself create the imagination of sounds? Yeah, I mean, the brain is always trying to form order out of disorder.

So if you're in a plane, there's a lot of noise when you think about it. I don't know what the sound level in a plane is. Trevor probably knows. So 80 dB, 90 dB maybe. So it's a pretty high sound level. But it's basically just noise. It's just a formless kind of sound. And because your brain's always trying to impose,

just like looking at clouds, you see faces in clouds and animals and things like that. So perhaps your brain is doing a good job of trying to extract some meaning from this meaningless noise. To me, that's an interesting thing. When we are listening to music, when we are listening to music when we listen to noises how much do we as human beings still place our own personality our own perception maybe maybe Trevor you know but how much in terms of our own perception changes what we might be

hearing compared to what other people are hearing? Well there's things which are culturally learned such the scales that we listen to so if I I go into Asia, their musical scales are quite different from the musical scales we get in Western countries. And if I listen to Asian music and I'm not used to it, I think it sounds a bit odd. But obviously that's what Asian people listen to. So we can learn what we want to listen to. So you can decide to associate anything you like. So we tend to associate minor scales, minor keys with sadness, but you could associate it with nice jolly things if you wanted. Can you really? Julian, perhaps you could give us a minor scale.

A minor scale sounds like this. Now, that does indeed, as everybody knows, sound sad. That's a sad song in a minor scale or a minor key. Is that learnt? Have we learnt that that progression, that harmonic progression, is sad? Or is there something inherently sad about it? I mean, lots of scientists have looked at this,

but the present sort of understanding is it's a learnt response. You might be hearing to these sounds, even from in the womb you can hear some music going on, and you start to associate these sounds with different events, and people will learn that that means sad. So could you test it then? If you kidnapped two identical twins and played one constantly major scales, happy, happy music,

but showed them images of train wrecks and haunted houses and graveyards and Sheffield United winning the Cup. And, you know, terrible events. And then had the twin with... A minor scale. A minor scale, of course, showing him Wednesday winning the Cup, showing lovers reuniting at train stations, candy floss, happiness. Would they... Would that completely reverse? Or would you just get charged for kidnap?

I tried to get ethical approval for such an experiment, but unfortunately the ethics committee wouldn't allow me to do it, so we'll never know. I mean, the experiment's kind of been done, right? Because in the Middle East, minor scales sound associated with happy music, right? Can you do it? That suggests that there's a tempo element to it.

Well, actually, Trevor, you might start by outlining what a scale is. So physically, what is it? Well, we can't play every single frequency that's available to us, because actually on a violin, obviously you can play a glissando and just have every frequency playing, but if everyone was playing any old frequency they like as a group, it would just sound awful. It would sound terribly distant and really horrible. So we have to know there's certain frequencies we have to hit

so the notes will go nicely together. So we know that if we have an orchestra playing and they're all trying to hit those frequencies, we've got a better chance of it sounding nice together as if everyone's playing any old frequency they want, where it'll just sound terrible. And why those particular notes? What is it?

We talked earlier about or mentioned the mathematics of music. So what is it mathematically that defines the notes that we happen to have chosen in the West? Well, it goes back actually to Greek, working out how notes are interrelated. So notes which go nicely together, I say a note and a fifth above. We'd like to just play that for us, Julian. Those notes just sound naturally good

together. And actually they're closely related mathematically. One's one and a half times the other frequency. So that we know when you play a note on an instrument, you don't just get the frequency of that note. You get all these harmonics, which are more multiples of those frequencies, and they come out as well. And how those different harmonics interact determine whether the notes sound nice together or sound nasty. And so our scales are largely constructed in Western music about how the different notes sound in pairs or in large groups in chords. Tom, what always fascinates me is how... I think it was Pythagoras that invented the idea that the fifth, as Julian played before, and the fourth...

..are so closely linked that anyone that's learnt a musical instrument will be aware of the 1-4-5 chord progress. Exactly. So Pythagoras unwittingly wrote the entire status quo. And that is why,

I mean, I think Pythagoras did some excellent work with, I love his A squared, B squared, C squared stuff, but it is why I won't have triangles in the house. But he was a founder member of status quo, wasn't he? Is Motorhead more Aristotelian, do you think? Now, Trevor, I know, moving away from music,

just talking about sounds in particular, I know you ran a research project at Salford, which is a mass online experiment to find the world's worst sound. I think over a million people participated. And I'd like to read out the top ten list, first of all. So the number one worst sound was vomiting, followed by microphone feedback, wailing babies, trains scraping on tracks, a squeaky seesaw,

a poorly played violin... It's still working! Yeah. A whoopee cushion, an argument in a soap opera, mains hum and the Tasmanian devil. Now, Tasmanian devil, perhaps that's a geographical response to the people. So let's take a few of those. Vomiting, why would that be the number one most objectionable sound?

I'm just amazed you didn't go from ten down to one. You had the chance to have the Top of the Pops music on and relive your youth then. You missed out. At one point we were going to have the sound effects for all these things, but thinking that possibly playing the top ten most hated sounds may well be a big turn-off. I'm turning over to radio too. But again, there must be some, I mean, from an evolutionary perspective, we must have some insight as to why sounds like that.

Let's take vomiting, for example. What is it? I know what it is, but... That's what I like about your science. We have to start with the basics. I mean, there's a well-researched phenomenon called the disgust reaction, which is meant to help us catch disease. So we try and stay away from things that might have disease in them, like vomit, for example. So we have a repellent reaction to bodily fluids and nasty stuff,

and that's meant to protect us from disease. So it would seem logical that the sound of someone being sick is going to be repellent because it's a sign of someone ill, maybe, who's carrying a disease that you need to get away from. I'm interested just in the audience, because I don't Tom, I mean, what would you put as your, you know, out of that list there, vomiting, microphone feedback, wailing babies, train scraping on tracks,

is there one there that you think... Train scraping is awful, microphone feedback, I can't stand. I mean, a lot of those overlap really, don't they? They're very high-pitched, scratchy sound. So what is it about high-frequency sounds? They seem relatively unnatural in this case. I mean, most of them are modern, microphone hum, trains, etc.

I don't think we really entirely know why they're very unpleasant, but one of the suggestions, which goes back to the early 80s work on this, is that actually these sounds are a bit like the sound of someone screaming. So you take fingernails down the blackboard, it's got a certain kind of frequency and a certain roughness to it that you also get if you let rip with a very big scream. So maybe there's a connection between the sound and distress cries, and that might be what we're reacting to

on a very simple level. But I don't think anyone's actually really done any experiments to show this is true or not. See, I think that... I don't know what other people think, but I disagree with... I'm sure I'll ask you... You can't disagree with that. No, I do disagree with it. No, no, no, I don't know. I certainly think, but I disagree with this. I'm sure I'll ask you, Tom. I disagree with that. No, I do disagree with that. No, no, no.

I certainly don't ask me for support. But I keep looking at this list. He's been doing this too. And vomiting. I understand vomiting, right? Fair enough. But squeaky seesaw, right? Vomiting.

Oh, no, someone's sick and they're full of disease. Squeaky seesaw. Oh, no, happy children. It's really, to me, I mean, there's some of these, whoopee cushion I don't see, in fact Trevor, am I right in saying you were once in the Guinness Book of Records for, did you possess the largest whoopee cushion?

I did at one point have the world record for the world's largest whoopee cushion And was this part of the research? No, I think the big whoopee cushion came after this one, that was a stage prop for stage show because actually a whoopee cushion, the output of it, behaves very much like, say, when you're blowing a trumpet or when you're at the reed of a saxophone or something like that,

so it was used as a prop to explain how musical instruments work. But unfortunately I lost the record to a friend who broke it, and the record currently is, I think, three metres in diameter. Is that all? And it was here that Tom saw his dream begin. I could train every day for five years. I'm not going to beat Usain Bolt, but I could make a whoopee cushion 3.1 metres in diameter.

The physics, unfortunately, defeats you, because what happens is you get bigger and bigger. It goes lower and lower in frequency, so it gets less and less impressive, and it's still got to make the sound. So there is a physics limit to how big the world's largest whoopee cushion could ever get. Dang!

Isn't it awful when a rude pop is defeated by the laws of physics? Yeah, totally. One of the other areas, just going to a broader pop culture area as well, is the way that sound is used, sound design, in popular culture. For instance, in films, where very rarely... The amount of orchestration you hear in the average film is we are constantly being manipulated to have emotions beyond just what we're seeing visually,

beyond the voices, what we're hearing. I watched Crime Watch the other day, and there was a sad scene where something sad happened. You knew it was sad because someone had died, but they still went, we'd better put some sad music on as well, because then they really know it's meant to be sad, not one of those funny someone had died but they still went we better put some sad music on as well because then they really know it's meant to be sad not one of those funny someone's died moments but this is you know sorry tell me can i tell you a story about when i was nine years of age um it depends on my ninth birthday right this is completely true my my granddad died right which was um both

disappointing as it was selfish um i thought you were going to... Yeah, yeah, you can... Shall I say that again over the top of that? OK. If you can just fake a comical reaction. When I was nine years of age, my grandfather passed away on my ninth birthday, which was as disappointing as it was selfish. Anyway, we went to the funeral, right,

and I'm from a very emotionally repressed family. I mean, it's just Yorkshire, so we're all a bit backward emotionally, but we went to the church, and I was only nine years. I was nine years of age, and in the funeral, I wasn't used to seeing the output of emotion from all the grieving relatives. It completely did me in. It completely floored me emotionally.

I was on the ropes. I was seeing everybody sobbing and weeping and hugging, and I'd never seen anything like it. So I was just in pieces, right? And then one note happened in the hymn. That note made me cry so hard, it almost turned me inside out. I can't describe the rush of emotions that went, whoosh, like that, out of me.

I had to be sent home from a funeral. I've probably been the first person ever to be thrown out of a funeral. I was sent home for a funeral, and then a few years later, we inherited the piano. My grandad didn't need it anymore because he was dead. So messing about on the piano I picked out this note and it's called the devil's note or something.

Can you do it Julian, just that one bit? That distance there is a tritone. It's three notes apart. And it does have a very special effect. It's really useful in music for giving an effect. I mean, it's interesting that we're talking about how different cultures perceive music and the way it works.

I think that, for everyone, has got to be spooky. And so I don't know if it's anything which is indigenous in the culture. I believe, as a musician, there are effects that you can make, that you can give to people just simply by what you play and that will work for anybody and i can frighten anybody with that so we were just talking that i mean in films for instance we were something we're chatting about for where you have when you you know hitchcock knew with bernard herman you know the incredible moments there where why why, can we just play,

I suppose the most obvious one is to go for Psycho there. Yeah, yeah. So that is, I presume, is that again, that's the nails on the blackboard, that's that kind of, it's putting us really on edge as if seeing someone in drag stabbing a young woman to death isn't enough. I think there is that sort of fingernails down the blackboard quality, but there's also the fact that it's repetitive and you don't know when it's going to stop.

And that's something which can add to horribleness, is if you keep doing it over and over again and you can't escape it. So we know if you haven't got control of a sound, your reaction to it is much stronger. And then something like the Jaws one, which again is probably one of the most famous ones. Can you do that on the violin? I've been looking at Jaws and it's really clever because he uses several

different techniques to get you to feel threatened. One of them is to start with one note. This should be on the cellos and basses who are over there. Or at least they normally are when there's a full budget. Couldn't afford them. Anyway, this is the pattern.

Which you all know. Immediately that sounds threatening. He adds another one. So you know something's approaching. Actually, this is not going away. Something more is going to... And then the next one is four notes. And then it speeds up. So it's

obviously getting not only closer, but more aggressive. So now, you really get the sense of something approaching. That's psychological. What I like, though, is that with the violin, rather than the cello there, it does make for a jauntier shark. It does.

It's a shark that's going to come out and then go, da, I'm out of here. We'll very quickly just go through the audience questions. We asked our audience, if you could take one sound to a desert island of silence, what would it be and why? We've taken out the 500 answers that were Brian Cox's voice saying everything's nice.

But, yes, we did note them, don't worry. Here's one from Ian Fitter. John Infinite Monkey Cage's track, four minutes and 33 seconds of silence, which is basically four minutes and 33 seconds of silence, just for the irony. I like, which is basically four minutes to 33 seconds of silence, just for the irony. I like anyone who's going to go to a desert island and go, I think irony will still be effective here.

We've got here the sound of rain to remind me of Manchester. The voice of Brian Blessed saying, Dive! That's in Flash Gordon, because I need cheering up. That's Richard Frost. Can you imagine that on a desert island every five... Dive! Oh, Brian.

The clucking of a gilded chicken. Now, you wait for this one. Because silence is gold hen. Pete Jackson, you know who you are. That brings us pretty much to the end. Thank you for those answers. There we are. Next week, it is the ultimate showdown.

It is chemistry versus physics. Not really any point to that show. But nonetheless, we've invited a couple of test-chief twiddlers and magnesium-stripped strumpets onto the show for amusement purposes, you understand. So, thank you to our guests, Tom Rigglesworth, Trevor Cox and Chris Plack. And we thought we'd end the show with a song.

We've been talking about the fact that songs, in many ways, almost feel adhesive to the brain and that you just really get stuck in your brain. So Brian has gone over to the Steinway that was flown up here from one of his houses. And I have to say, this wasn't my choice, this song. I'd like to apologise for the fact you're all going to go home with it. It probably won't leave you for days.

Here's Brian and Julian with what I think is going to be a number 27 Christmas hit, Abba. Thank you and good night. That's the night you take to drive safely. If you've enjoyed this programme, you might like to try other Radio 4 podcasts, including Start the Week, lively discussions chaired by Andrew Marr, and a weekly highlight from Radio 4's evening arts programme, Front Row. To find out more, visit bbc.co.uk slash radio4. This is the first radio ad you can smell. The new Cinnabon Pull Apart, only at Wendy's. It's ooey gooey and just five

bucks with a small coffee all day long. Taxes extra at participating Wendy's until May 5th. Terms and conditions apply. In our new podcast, Nature Answers, rural stories from a changing planet, we are traveling with you to Uganda and Ghana to meet the people on the front lines of climate change. We will share stories of how they are thriving using lessons learned from nature. And good news, it is working. Learn more by listening to Nature Answers wherever you get your podcast.