sound has a kind of magic some creatures see with sound and so do some blind people some can be shaped and engineered to enhance beautiful music

zone can even change the taste of food sound can burn away tumors and may soon treat Alzheimer’s disease some can levitate solid objects the mysteries of

sound are coming into focus like never before look at that geometry oh my goodness

when people try to explain what sound is they often liken it to ripples in a pond a series of travelling compression waves radiating outward from the source

we can make a graph of sound we can measure the level of sound we can record the intensity of sound but a real picture of sound is more complex

sound effects matter in surprising ways a mystery that has recently deepened cymatics is the science of visible sound so all we have is a metal plate and we

sprinkle on some sand what you see here is completely formless in other words there’s no pattern at all then we take a violin bow and we’re

going to play the plate with the violin bow you see a beautiful star appears on the plate now that pattern that forms is basically the sound made visible and

it’s kind of magic and now watch what happens when we make this plate vibrate from an electronic piano

isn’t that neat John Stewart Reed of Kazik England is the co-inventor of a new instrument called the cyma scope it converts sound into three-dimensional geometric images in water

what’s happening is the sound is actually compressing water molecules under the surface and actually creating a kind of lensing effect to allow light to bounce off those subsurface structures so here you see that there’s a pattern forming in the center if I put my finger in you can see what happens that it actually disturbs the pattern completely the pattern is now gone it’s

gone into chaos if I take my finger out again and leave it for a second or two to restabilized you can see that the pattern starts to come back again so that’s really

interesting isn’t it here we have the beautiful song of a humpback whale some of this geometry that we’re seeing is just exquisitely beautiful when we look

at some of the other cyma scope images we are seeing so many forms that resemble early life forms in the ocean the cyma scope may someday help us

determine whether this is just a fascinating coincidence or new evolutionary biology sound has evolved into a primary alarm system because we can hear danger even

before we see it lots of animals who’s a hearing to avoid be even it serves a kind of an omnidirectional monitor for things that are happening in the environment sound is the sense that

never sleeps the brain listens even while you dream if you’re sleeping you’re not going to be awakened by most sounds say suppose you’re attuned to the

sound of a baby crying that will wake you up because your brain has learned that that’s something important for you and it will go right through whatever your defenses are to keep you asleep and

you are awake but sometimes sound plays tricks on the brain bouncing around causing echoes and turning words to mush solving problems

caused by sound is what acoustic engineer Trevor Cox does for a living I did a physics degree and I was always a musician and it was a kind of a way of combining my interest in music and

physics together Cox records sound in art spaces here with a headlight device that mimics human hearing I just got fascinated in how architecture changes music and enhances

and beautifies it sometimes it’s about making music beautiful other times it’s about speech it’s about trying to communicate at the Town Hall in

Manchester England Cox explains the hearing problem caused by reverberation  when I talk in the building you don’t just get the sound straight from my

voice you get the reflections off the floor the walls and the ceiling and each reflection arrives at the ears at a slightly different time that amplifies

my voice and it’s one of the reasons it’s very easy to project your voice in this space like this but it’s not very

good for speech because the words start running into each other’s previous word lingers mingles with the next one it

makes her a bit unintelligible to hear an extreme example of this go to Pisa Italy where there is a second less famous tower called a Baptistery of

Saint John here opera singers demonstrate some remarkable acoustics by singing notes that lingers so long in the air a singer can harmonize with

himself  each note lasts a full nine seconds good acoustics are more than just entertainment if the announcements in a train station

for example are garbled passengers might miss more than the orient-express you know it’s about life-or-death situation if someone’s being evacuated because there’s a fire

or bomb alert so it’s more than just being able to hear the announcements acoustic engineers in a studio like this

in Manchester can clean up muddy speech by creating a computer model of the station and then tweaking the sound system or the building’s acoustics but

we can use a much more directional loudspeaker which has aimed at the passengers and away from all the reflective surfaces in the room if we

add some sound absorbing treatments and in this case it’s to the soffit all along the top of the structure hopefully much better intelligibility for a

theater or concert hall designer sitting in the sweet spot of this lab provides the chance to hear what their building will sound like before it’s built and compare it with some of the best

acoustics in the world I’m gonna take you to the Boston Symphony Hall in the US the secretive Symphony halls

virtually perfect sound is in the math the equation written in the 1890s by Harvard physicist Wallis Sabine

using a pipe organ and a stopwatch sabine made thousands of measurements to calculate the ideal ratio between room volume and sound absorbing materials

with a reverb time of 1.9 seconds Symphony Hall is considered one of the top concert halls in the world and the Sabine Equation underlies the software

that allows acoustic engineers ping chen and gary mac to fine-tune the sound of a modern performing arts center they start

by measuring the time it takes for sound to bounce off the walls and the ceiling keeping in mind the ideal times for

voice and music they create a computer model of the soundscape what they call an aural ization the back walls below the balcony that’s going to be the

longest reflections that we’re trying to control which allows them to customize the way a room sounds depending on what

it’s used for those acoustical panels they’re retractable so for speech we’re going to have them in place but for music we’re going to retract them because we really want the lateral

reflections for music so these reflectors should probably be a little bit lower a series of mobile panels converts this theater stage to a music venue in a matter of minutes

we make the space sound like it’s supposed to sound people respond to sound in varying ways much depends on who’s listening and what’s making the sound usually the

sounds of nature even when loud tend to be less annoying than the sounds of modern life but how much is too much a decibel meter measures the level of sound pressure normal conversation is

roughly 60 because the scale is logarithmic 70 decibels is twice as loud hearing protection is recommended at 85 about 90 sound is damaging prolonged exposure to noise at this level causes

hearing loss pain begins at 125 loud sound produces a fight-or-flight response stress anxiety increased heart rate loss

of sleep fatigue and social conflict have all been linked to louder environments

psychologist Alan Polyakov of the University of Manchester has studied how sound even affects the taste of food for this experiment we wanted to target

specifically salty flavored foods and sweet foods we asked participants to wear the headphones so there was one condition where there was no noise at all when where it was quiet so this was

45 to 55 decibels or louder noise which was the 75 to 85 decibels the participant would close their eyes so they didn’t know which of

the foods was coming and they would reach out and then they would eat it people found that they rated the food less sweet and less salty in the presence of their background noise this

may explain why airline food often tastes bland one theory is that high background noise prevents the brain from

fully processing other sensory input they white noise actually distracts you from processing the taste as much as you might otherwise do so so it appears less strong to you because

you’re distracted the volume of sound in cities everywhere is constantly changing sounds that used to be strong and clear [Music]

are getting lost in the din of urban noise so isn’t that a great sound right

right in the center of Vancouver very true axe is an emeritus professor of acoustic communication at Simon Fraser University drew axe believes the preservation of iconic sounds or sonic

landmarks is just as important as preserving a city’s visual landmarks he and a team of researchers set out to measure how far away they can hear the bells of Holy Rosary Cathedral his

concern is that the roar of the street is drowning out the city’s historic sounds it really began in the early 1970s with a much more ambitious title

the world soundscape project the canadian composer armory Schafer who taught at simon fraser university decided that instead of being just anti noise that would be much more positive to create a soundscape approach which is sound marks as aural landmarks and so first of all it gets everybody thinking well what is a special

and there you have it one of arguably the most unique sound mark in Canada first four notes of the national anthem for almost 50 years now that sound has become a part of the Vancouver

soundscape and probably is the most recognizable one outside of Vancouver what Murray Schaefer created with the world soundscape project was a whole new

field of study called acoustic ecology it’s essentially an aural ethnography right that you actually understand society like an anthropologist would but using your ears and not just your eyes

these bells used to be heard all over town now even if you listen carefully even if you can still see the bell tower the sound is lost after a few city blocks

so there you go there’s a difference between the acoustic world is the mechanical girl laughs o’clock a hundred years ago they could talk about listening to the beautiful chimes of the Holy Rosary

Cathedral in the Hillcrest area and also South Vancouver you know how many miles away that is a hundred years ago Holy

Rosary was one of the tallest buildings in the city today it’s lost in a concrete forest if the ringing could be heard in

Hillcrest nearly forty blocks away then the acoustic profile of the bells has shrunk to less than a tenth of what it

was but this is only part of the story The Sound of city streets in Vancouver was entirely different a century ago the only moving pictures from those days

shot from the front of a streetcar are silent but with the same technology used to create movie soundtracks it is possible to experience what the city

sounded like in 1906 when the bells were new I’m trying to make people jump into the scene and live the scene so I thought well maybe what we’ll do is we will play a bit of the scene looking

around us and see what we hear this is only two blocks away from the Holy Rosary bells so have you tried putting those in for sure

right notice how they’re really audible over everything else that kind of traffic

didn’t dominate like it does now I mean this is all on a very human scale watching all those people racing across

the street it looks actually positively dangerous so they obviously are relying on their ears as well as her eyes to

tell them what was going on the sounds are clear and distinct and it isn’t

dominated by just one sound such as traffic would be today the point according to true acts is that cities

have always been loud but back in the day it was allowed you could live with

take a tour of Venice and you’ll hear what city’s sounded like before the

Industrial Revolution once you get away from the vaporetto transit boats and

slide into the narrow little canals called Rios you hear what the world

sounded like before internal combustion instead of gasoline and diesel engines

you hear voices and footsteps but even here sound has long had an uncanny power over people’s lives and as

it turns out people were constantly listening to their city and this was the came as a huge surprise that they were

listening to their buildings they were listening to the way in which the city talked to them in various ways art

historian Niall Atkinson is fascinated with the way sound organized the work

day long before radio TV and the internet and even Holy Rosary in

Vancouver bells were a primary means of communication before people had watches

the sound of bells controlled their every waking moment and it wasn’t just

the church that rang them the big-mountain gonna that rings in that tower that signifies that the

dockworkers have to be in the arson alley or during the day bells will ring to make sure that magistrates are in

their council halls that lawyers and jurists are in the courts by the time

that the bells finish everyone has to be in place so there’s this kind of acoustic organizational choreography to

the daily rhythms of the city the same was true in other Renaissance cities

such as Florence here the city’s first town hall had its own bell tower to

rival the ringing from the church’s main cathedral the government’s Bell had to

be the biggest and the loudest big enough and loud enough from a tower high enough in order to establish their

legitimacy and authority over the city so what the regime was doing was acoustically trying to insert itself

into the sounds that the Christian Church had been making for centuries [Music]

but it wasn’t just City Hall and the church that wanted to control sound in

1378 wool workers who toiled at looms like these who had no voice and

government launched a revolution by seizing control of the bells within a

few minutes eight bell towers around the periphery of Florence were ringing to signal and coordinate what turned out to

be one of the first if not the first successful worker revolution in Europe having hijacked the bells as many as

10,000 workers swarmed into the public square outside City Hall to voice their

demands and this is exactly what happened in Tahrir Square in 2011 when

Egyptians gathered in the square who wouldn’t stop making noise who would not leave the bells were the Twitter of

their day the sound of the crowd penetrated the walls of the palace so much so that the

government gave up they came down they handed the keys to the palace and they literally went home the people had

finally one noise is a natural by product of human activity so silence or the use

of quieter technology has become a valuable commodity in our loud cities from a distance you can’t hear us at all you can’t smell us either children right

out of Vancouver has created a landscaping company that works entirely without gasoline-powered tools back in

the bad old days we used to be covered in two-stroke and you’re in a wall of sound all the time and covered in dust now you’re just covered in dust at first

right outs new company did everything by hand then technology changed the electric equipment we have is all lithium battery power so we’ve almost got the Tesla’s of lawnmower equipment

this equipment does make noise but only half as much as internal combustion engines what I heard on a regular basis was we’re so tired of the noise we’re

tired of the smell we’re tired of our entire day being interrupted when at landscape meaneth

company shows up you’re not gonna get away from noise but anything that can be done to reduce it it just it helps with stress levels what we’re talking about

affects everyone whether you say oh I can get used to it doesn’t bother me or something like that but it always has an

effect both physiologically psychologically and in terms of communication it’s in many

cases the soundscape that gives you a quality of life what if sound where your primary means

of finding food your main method of survival that’s how it is for big brown bats bats of really neat animals and they have to be able to do everything

without relying on vision James Simmons a professor of biology at Brown University in Providence Rhode Island is setting up a maze of plastic chains he

and postdoc Kelsey hum are testing the ability of bats to navigate with sound to help improve sonar navigation by humans bats are very comfortable flying

through the branches and leaves of vegetation and while they’re doing this they’re looking for insects and they’re

flying several meters per second so the experiment uses a slow-motion camera and simulates the bats natural environment so the way we thought to do this is to

replace the vegetation with these black plastic hanging chains to get something acoustically very similar to a whole field of vegetation

because the sound a bat makes is beyond the range of human hearing Simmons uses an ultrasound detector to convert the signals to a frequency we can hear

Simmons is particularly interested in how a bats brain is able to process sound signals and perform complex mathematics at extremely high speeds so

the bats emit sounds and do lots of fast computations in the brain about the arrival time of the echoes coming from different distances and the trick of sonar is to be able to do these

computations quickly enough but you can see the scene before you emit the next sound we can’t do that with our digital

computers because they’re not fast enough the fascinating discovery is that bats actually form 3d images based on sonar echoes when we see something with vision

we see color and we see texture and lots of things like that the sonar image that a bat gets of an insect is stripped down

to only three or four body parts the bat will aim its sound at the insect and get a bunch of echoes from the different parts of the target but when it’s chasing the insect it doesn’t go straight toward it it follows a curved path so that each time it emits the sound it’s getting a slightly different angular view of the target and by

rotating this way the bat gets to see the parts of the object in their real three-dimensional locations that’s actually see with sound perhaps even more astonishing is the fact that

some humans are able to do the same thing so I’ve got a tree here I’ll turn

here by 13 months of age Daniel Kish had lost both eyes to a cancer called retinoblastoma instinctively he soon began to make clicking sounds and

started to echolocate just like bats do those clicks you hear are from his mouth not the tapping of his cane big open area but we’re approaching a structure

he calls this flash sonar flash sonar has become Keisha’s primary means of navigation so in my case it wasn’t something I was really aware of it just

happened as a consequence of my childhood experiences I get an image that occurs in a 360 degree field the

roof structure were under isn’t totally solid somehow it’s got openings in it as if it were slanted or I described them as fuzzy geometry moving dynamic figures

they have depth and contour and character and they provide me with information about location density and you can also kind of hear things around

corners and you can hear things through objects so you know it almost has this kind of omnipresence about it as a kid I was raised to think of myself as is pretty unremarkable my parents

their emphasis their regard for me was you’re you’re a kid like any other kid he got his first bicycle at the age of six I learned I learned to click like a

maniac and I learned to ride around the neighborhood and if I ran into a pole my parents just didn’t make a big deal out of it running into a pole is a drag but never

being allowed to run into a pole is a disaster riding a bike blind has become a kind of stunt he does to raise awareness that the brain can adapt and that people can do far more than they

realize fifteen years ago it was just unheard of so if you don’t close your eyes for just  a moment okay and you’re going to learn a bit of flash sonar now you have

scientists studying and you have instructors wanting to learn it you have instructors wanting to teach it you have blind people wanting to learn it being

able to navigate comfortably in any environment under any circumstances nothing can be more fundamental to freedom than being able to do that we

asked him to draw a picture to recreate from memory the image he got from nothing more than the sound of clicks I’ll just do a little dashed line here

and remember he had never set foot in this pavilion before today and then we had another column kind of across the way here definitely taxing my artistic

merits here should I say tada tada the accuracy of the image is uncanny it shows that there’s an actual imaging

process taking place you’re using sound instead of light to create a picture okay well I was right about the roof so

humans can seed with sound just like bats but bats have an advantage they aren’t affected by noise back at Brown University in Providence

professor Simmons explains that bats normally live in a very loud world the sonar sounds of many bats are 120 to 130 decibels of sound you have 50 bats

all flying around in the same small space all the bats in that space are exposing themselves to this intense sound and they appeared not to suffer the noise induced hearing loss that

follows that something that we would normally suffer and we need to find out what it is they’re doing to protect themselves [Music]

in the course of a human lifetime loud sounds cause physical damage to the inner ear tiny hair cells in the cochlea converts sound waves to electrical

signals that go to the brain the cells most prone to noise induce damage are the ones that act like an amplifier for soft sounds with hearing loss people

have cochlear damage those outer hair cells get damaged so you lose the amplifier basically you lose the knob for turning it up on your stereo system but noise induced hearing loss is only

part of the problem as we age the brains processing of audio signals slows down making speech harder to understand so it’s not just the question of turning up

the volume our auditory system is able to pick up little small gaps in speech a common example is the word say versus stay the difference between say and stay

is actually a little pause right when the T happens these are actually scalp recordings that we record through EEG on the right here we have a 16 milli second

guy and it would be akin to trying to process the sound stay there’s a little gap at when the T happens with age-related hearing loss these gaps are harder to detect so T’s and other

consonants become muddy so you can hear you know AEIOU but you’re having trouble

with the consonants that are surround those vowels at the University of South Florida in Tampa scientists are testing a new drug that might help in a study

that began with mice they learned that the drug can improve some perception by stimulating nerve channels in the brain there are little channels that process

potassium nerve cells rely on the proper concentration of potassium the new drug adds potassium to these sound processing channels as you age the number of these

channels declines the drug will increase the activity or the effectiveness of the remaining channels we are ready to do some EEG testing this is where we’re

gonna after the Florida team successfully tested the drug on mice the US Food and Drug Administration approved a Phase two clinical trial on humans what we’re gonna do is put this

electrode cap on he’s going to listen to some sound sources and what we really want to see is changes in the central auditory processing as they screen potential patients for the drug trial they’re looking for people who have a hard time detecting those sound gaps who have a hard time hearing consonants and understanding words especially in a noisy background and whenever you hear

that rare high-pitched beep I just want you to hit the spacebar for me okay because the drug is designed to make speech clearers not louder that would be

the the homerun for this study if it actually improved their ability to hear speech and understand speech and background noise in the future a pill

may repair hearing loss the future of sound even looks like magic sound waves from a bank of speakers can levitate solid objects by

focusing sound from opposite directions researchers have created what are known as standing waves that can actually

suspend objects in mid air floating 3d graphics microgravity and drug research are some of the possible future applications sound has already

transformed medical science when researchers at Brigham and Women’s Hospital in Boston married an MRI scanner to an ultrasound device everyone knows ultrasound as the imaging tool for

expecting couples this team is using sound to burn away tumors a form of surgery without a cut or a single drop of blood by focusing the ultrasound beam into tissue somewhat akin to the way we would do with a lens and the sunlight sound waves will cause a local vibration of the molecules in the tissue that motion causes local heating and that heating

therefore can kill the cells in that area so that thermometry is the really key part that the MRI brings to this procedure but no other procedure no other imaging tool can do we’re seeing in real time the signal intensity changes you see how this area has become white but that shows me that that’s exactly where the energy is being

deposited inside her fibroid once we get above 55 degrees C the cells are dead but this is just the beginning MRI guided focused ultrasound can take

away the pain of bone cancer there are clinical trials with prostate cancer and breast cancer and many more the most exciting one right now that’s in clinical trial is the one that’s

actually being used to stop intentional tremor so intentional tremor is when patients develop like this what I’m doing with my hand and are unable to write or eat or feed themselves and this

technique when targeted to the correct part of the brain stops that tremor immediately with this technique they can now use a transducer around the head and allow the ultrasound enter the brain

non-invasively and that’s leading to some very exciting applications for example in Brisbane Australia another form of ultrasound is being tested for treatment of Alzheimer’s disease juergen Gertz and gerhard lie ninja set up an experiment using mice born with a gene mutation that produces the amyloid plaque associated with alzheimer’s as naturally curious animals normal wild

mice will explore all three parts of a why maze but mice with Alzheimer’s can’t remember where they’ve been before and tend to explore the same area over and

over again pulses of ultrasound gently opened the barrier that protects the brain from infection allowing a protein from the blood to stimulate waste removal cells

that clear out the toxic clumps of plaque we use pulsed a croissant and because it’s passed the tissue is not heating up after the ultrasound treatment when the mice enter the maze again they’re able to explore just as well as healthy mice and the nice fingers will show a restoration of memory function so basically we are able to restore memory

functions to what find finds in non Alzheimer’s mice and I’m highly confident that what we have found in mice can eventually be translated into

humans so the sound we can’t hear is curing disease and the sound we can hear shaped our history brings harmony to the structures we build helps us navigate

the natural world and creates fascinating geometry that may hold the key to other mysteries sonic magic indeed