If you stand in front of a classroom full of kindergarteners and ask them what an ear is, chances are good that they'll think you're kind of silly. Everybody knows what ears are, those floppy things on the sides of our heads, the things we hear with but what if you were to pose that same question to a classroom full of spiders? Dr. Natasha Mhatre: So this is going into the fun part of my Dr Natasha Mhatre researches how insects and research.
spiders process sound at the University of Western Ontario, and she says that scientists used to think that spiders couldn't hear airborne sound because they didn't seem to have any obvious ear like structures. Dr. Natasha Mhatre: That used to be the received wisdom. There's now different pieces of evidence from other labs, including some evidence we've just collected that suggest that they can hear airborne sound. Where would their ears be? Dr. Natasha Mhatre: So that's the big question.
Natasha says she and other researchers are now coming to understand that it's not necessarily that spiders don't have ears. They might just look really different than ours. Dr. Natasha Mhatre: Okay, so there's some evidence that one of the ways that they hear is when air hits the web of some spiders, it makes the web move, and they can sense the vibration of the web, so they're kind of making their own ear drum. The web is the ear. Dr. Natasha Mhatre: The web is the ear. How cool is that?
Dr. Natasha Mhatre: That is pretty neat, because you can make whatever ear you want, right? If it gets damaged, you can just make yourself a new ear. Really cool. Welcome to Threshold, I'm Amy Martin, and we're going to hear a lot more from Natasha in our next episode. But I wanted to start out with this fun little factoid about spiders just to shake up our perceptual framework. We
think we know what ears are. We think we know what it means to listen, but those ideas are usually just drawn out of our own very limited experience. And speaking of things we think we know but maybe don't, what is sound? Like, if you had to define it right now without looking anything up, what would you say? Even though I work in audio, I didn't really have a clear answer to that question before making this season of our
show. Sound is one of those things that's so much a part of my everyday life that it's easy to forget how mysterious it really is. It's everywhere, but it's invisible. It's flowing into my brain every waking moment and when I'm asleep it turns out, affecting my mood, my energy level, my sense of connection to wherever I am and whoever I'm with. But what is it
actually? The answer to that question is not as straightforward as you might expect, so in this episode, we're going to press pause on our timeline of listening to examine the nature of sound itself, what it is, how it moves, and how wildly different our experiences of it can be.
We're going to tap into a secret communication network happening all around us, pay another visit to the dolphins of Shark Bay and talk to a world famous composer about how much more there is to listening than what meets the ear. I'm walking through a Montana forest. The breeze is rustling through the trees. There's a creek flowing nearby, and one of my favorite birds is unleashing its song again and again. It's a Swainson's thrush, and I love its song. I think it sounds like
a waterfall flowing up. Chances are good that you have a bird song you love too, and even if you don't, almost all of us hear birds singing every day. So in a way, this experience I'm having is completely ordinary. But if I zoom out a bit and think about what's actually happening here, it's kind of marvelous.
Something that originates inside the body of a small bird hidden in the branches above me is traveling across the forest and landing inside my ears and ultimately in my mind, where it becomes this beautiful, melodic thing with the power to change my mood and lift my spirits. I'm receiving something from this thrush, something is being transferred between us, and it's affecting me. But what is that something exactly? What is sound?
Dr. Lily Wang: So at its heart it is an energy in the form of vibrational waves in matter. Dr Lily Wang is an engineer who teaches and studies acoustics at the University of Nebraska in Lincoln. She fell in love with sound as a child the way many people do: through music. Dr. Lily Wang: I love singing. I have loved singing since I was a little girl, and I've always been in choirs, and then I did also play piano.
I asked Lily to give me a crash course in the fundamentals of sound, and she started with the fact that there's a wide range of sound waves, and we can only hear a portion of them. Dr. Lily Wang: We call it the audible range. The most common definition of the audible range is 20 hertz to 20,000 hertz. To help make those numbers mean something, here's a tone moving across that whole range. It takes about 30 seconds. But this so called audible range should really be called the
human audible range. Elephants, pigeons and many other animals can hear well below what we can detect, that's called infrasound and all sorts of other creatures can hear way higher than we can in the ultrasound range. Dogs can pick up frequencies twice as high as our upper limit. Cats can hear four times higher. And many dolphins can hear seven or eight times higher than us, up to 150,000 hertz. That's higher than almost all other
vertebrates on the planet, except bats. Again, humans top out at around 20,000 hertz, or for many of us, significantly lower. Dr. Lily Wang: I really can't hear above 8,000 hertz anymore. You know, there are bats in my house at certain times of the year, and I cannot hear them. Like I can see my children go... woo!..they twist their heads like they can hear that the bats are back and they're nesting, sadly, in our house, and they're like, squeaking, but it's at like, it's probably at like, 10,
12,000, hertz. I do not hear it at all. Here's what 10,000 hertz sounds like. If you're not hearing anything, don't worry. You are definitely not alone. Dr. Lily Wang: It's the most common disability among humans is that we lose hearing and most often at that higher frequency. In fact, some amount of hearing loss is almost inevitable as we age and of course, some people don't hear
any airborne sound at all. We're going to talk to one of those people later in this episode, but Lily says this measurement of how we hear sound waves moving through the air is really just one relatively narrow dimension of our lived
experience of sound. All kinds of other factors affect our listening experience, the temperature and humidity of the air, what other sounds are happening at the same time, the shape and texture of the space we're in, and that includes the most intimate space of all, our own individual bodies. Dr. Lily Wang: The shape of your ear, the shape of your head, the shape of your body, all these things are affecting how that sound wave approaches you. This is why our voices sound weird in our own
ears. When we hear ourselves on recordings, we're actually experiencing the sound very differently when it's coming at us in the air through a speaker, versus hearing it from inside the place it's produced, the resonating chambers of our own bodies. Dr. Lily Wang: The fact that we are part of this experience does actually morph how that wave gets into our head.
So you and I could be walking right next to each other listening to the same Swainson's thrush calling in the forest, and the differences in the shapes of our bodies means we'll be hearing slightly different things. But however the sound waves are ultimately received, they all start the same way, with a vibration. Dr. Lily Wang: Something that is moving, something back and forth. From there, a whole lot of things happen one after
the other really, really quickly. So let's try to follow the journey of that Swainson's thrush song step by step, from creation to reception. In birds, as with humans, song begins with breath. This thrush pushes air out of its lungs and through a special organ called the syrinx. It's set up differently from the human larynx or voice box, but the basic concept is the same.
The bird squeezes the muscles around the syrinx, setting air molecules into motion, and when it opens its mouth, that vibration is then passed through the air, molecule to molecule like a baton. Dr. Lily Wang: It's pushing these particles, which push the next particles, which push the next particles. It's an incredibly fast relay race, moving from the bird across the forest and into my ears.
Dr. Lily Wang: But once it gets into the ear, it's traveling down and it eventually hits a membrane that is physically attached to three of the smallest bones in your body. That membrane is called the eardrum, and it is a lot like the tight, bouncy top of the drums we use to make
music, except it's only about a centimeter wide. That's less than half an inch, the vibrating molecules of air hit that drum, making it shake, and that causes those teeny, tiny bones called the ossicles to move, one after the other, which shakes a second membrane... Dr. Lily Wang: ...that is then connected to fluid inside the cochlea.
The cochlea is a fluid-filled tube coiled up like a snail shell or the world's tiniest cinnamon roll, and when the vibration that began with the breath of the bird is transferred into the cochlea, it sends ripples through the fluid inside, almost like waves rolling across a miniature ocean. And lining the inside of the cochlea, swaying in the fluid, guess what we find? Cilia. Tiny little hairs like
the ones that grow on the bodies of baby corals. Under a microscope, they look like sea grasses, flexing and bending as the waves of sound roll over them. And as they move in response to the sound energy, the cilia perform one of the greatest magic tricks in the human body. They transform this physical vibration into a spark of electricity, which then shoots off to the brain through the auditory nerve, where we process it as a sound.
Dr. Lily Wang: And all this happens so fast, like, so fast, like, in an instant! 343 meters per second, give or take, that's more than three football fields in the snap of a finger. Dr. Lily Wang: So quickly. It's just miraculous. So to recap the process, the vibration starts in
the body of the bird. That energy is passed across the forest into my ear canals, where it hits the drum that moves the bones that hit the other drum that shakes the fluid, which bends the cilia that turn the vibration into electricity that goes to my brain, in less than a second. And that's the simplified version, but as quickly as this vibration is transferred from the bird to me as I walk through the forest,
the movement of sound and air is actually relatively slow. Sound moves more than four times faster in water compared to the air. Dr. Stephanie King: This, this.
This is what we do. Dr. Stephanie King: This is it. This is paradise.
We'll have more after this short break. Welcome back to Threshold, I'm Amy Martin, and I'm in Shark Bay, Western Australia, scanning the horizon for dolphins. I keep seeing something way out there. Dr. Stephanie King: Yeah, that was another dolphin. Yeah, yeah. That's Stephanie King, co-director of Shark Bay Dolphin Research. Dr. Stephanie King: So we're approaching what we call glass.
There's hardly any wind, and then you really see how many dolphins there are in Shark Bay, because you just start to see them everywhere. So cool. In our first episode, we met Stephanie and her field team and a few of the two or 3000 dolphins that live in these waters. Now it's the afternoon of that same day. The heat is upon us, the wind has died down, and we're moving slowly across the water. It's the most beautiful, blue, green water, it's just perfect.
Up ahead, a small group of dolphins is gathered at the surface. They're not swimming or jumping. They're just kind of hanging out there in the calm, quiet waters. Stephanie explains what's going on. Dr. Stephanie King: You'll sometimes see dolphins in Shark Bay, what we call snagging. This is when they're resting at the surface, so the whole body's just flat on the surface. And it was because in Australia, you snag sausages on the barbie,
like snagging. They're called snaggers on the barbie, and it looks just like a sausage lying at the surface. But these floating sausages are actually much more active than they appear. A dolphin doesn't lose consciousness when it rests, or at least not all the way. Half of its brain remains engaged in the work of breathing, which it needs to come to the surface to do, and stays alert to what's happening around it, and that means listening.
Researcher Laura Palmer flips on the speaker in the boat connected to the underwater microphones, and we're suddenly dropped into a conversation. These are echolocation buzzes, pulses of sound that the dolphins send out in order to gather information about their world. Dr. Stephanie King: They wait for the returning echo, and so the closer they get to a fish, the more they are echolocating so they can use their returning echo to work out distance and shape.
It's remarkable to be able to listen in as the dolphins do this, but it would be even more mind blowing to experience these sounds the way they do. Dolphins aren't only detecting a much wider range of sounds than we do, the whole nature of their sonic experience is something we can only sort of guess at. These echolocation buzzes are beams of acoustic attention, and they come back to the dolphins packed full of information that their brains have evolved to process at lightning speed.
So what sounds to us like a continuous buzz, to them, it's like really fast echo locating happening? Dr. Stephanie King: Exactly. Really, really fast clicks. So they're like pulsed vocalizations, and they produce them so rapidly, so sometimes it sounds like it's almost a continuous vocalization. Dolphins can actually use echolocation to perceive the insides of objects. If I jumped in the water with this group, they'd be able to sense not just my outer
surfaces, but my bones and lungs. They would perceive me in a way I could never perceive myself, and they'd be doing it using sound. Dr. Stephanie King: Here we go, snaggers. We've come upon another group of resting dolphins. Dr. Stephanie King: Snagging, see. Just resting at that surface, like a... Sausage on the barbie. Dr. Stephanie King: Sausage on the barbecue. Exactly. Stephanie says dolphins use echolocation
primarily to help them find food and for navigation. But even now, when they appear to be doing little to nothing, there is some echolocating going on. It's like they're casually scanning the environment, just keeping the ear out, except that ear isn't where we might expect it to be on their bodies. Dr. Stephanie King: They receive sound through the lower jaw, and
that sound then goes up to the middle and in the ear. So when they're snagging like that and resting, you sometimes see them their lower jaw is still in the water, and they're kind of moving their head side to side, as if they're scanning, right? They're not vocalizing. They're actually listening for sounds of
other dolphins, if you like. So we typically see that when maybe they're waiting for a dolphin to catch up, or there's about to be a join, and they'll turn around and they're scanning, and they've obviously detected something, and then they're having a good listen to see who might be close by. But with dolphins and other animals that live in the water, the whole idea of close by has to be redefined.
Acoustic vibrations don't only happen faster underwater than in air, they also do a better job of holding on to their power as the vibration is transferred from molecule to molecule, it doesn't lose as much energy with each pass of the baton, and that means underwater sounds can stay loud for a much longer time. So what feels very far away in human terrestrial life might feel quite nearby to a fish or a seal or a dolphin.
And Rockette just surfaced 80 degrees.
There's a little flurry of extra buzzing from the group as a dolphin named Rockette pops up and joins them, but there's no visible change in the dolphins' faces. It's not like they're opening their mouths to echolocate. I asked Stephanie how they are producing these sounds, and she says, as with our vocalizations, it begins with air pushing through tissues in the dolphins' bodies.
Dr. Stephanie King: They basically have these phonic lips, these two lips they can push together and then force air through that then causes vibrations of different tissues within that chamber. And it's the tissue vibration which creates the sound, essentially. I love how they're performing, right on cue, as you're talking about it, they started doing it. Dr. Stephanie King: Yeah! That vibration then passes through a pillow of fatty
tissue in their foreheads called the melon. It acts as a sort of acoustic lens, focusing and amplifying the sound, which is then project it out through their heads. We think of making sound as one thing and receiving it as another, but one of the things I find most intriguing about echolocation is that it's both at once. It's a way of making sound in order to listen. It takes the whole idea of active listening to a completely
different level. Dolphins can decide to shoot a beam of listening toward another dolphin or an approaching fish, kind of like the way we might flip on a flashlight in order to see into a dark corner of a room. And they can manipulate that echolocation beam, they can make it stronger or weaker, wider or narrower, and if something attracts their attention, they can turn up the dial instantaneously and send out a bright, strong pulse of acoustic energy homing in on whatever it
is they want to investigate. That's what seems to have happened with Rockette, because she suddenly left her group and zoomed right under our boat. Dr. Stephanie King: There we go, Rockette in the bow. Hi, Rockette! Oh, hi. Hey, beauty. Oh, right underneath us. Oh, my gosh. I mean I can reach out my hand and touch her. Wow. It's not us she's curious about it's a patch of sea grass below us in the crystal clear water, we can see her twisting and turning herself through it.
Dr. Stephanie King: So we saw Rockette just come up and rub herself in a sea grass patch. And we see that a lot with the dolphins, and we'll call it seagrass play. Or they seem to come up and drape it over their body and even rub themselves against it, I think just because it feels nice. But you see that quite often. And she obviously peeled off from the group, spotted that seagrass patch and went over there and started rubbing herself underneath it before returning to the group.
It looked a little bit like a dog growing on a mat. Dr. Stephanie King: Yeah, exactly, and you know, they do that. It's fun. They enjoy. It feels good. Same for the dolphins. Lots of animals use echolocation, orcas and sperm whales, some small burrowing land mammals, and, of course,
the most famous echolocators of all, bats. The common denominator here is darkness, where vision is diminished, the clicks, chirps and buzzes of echolocation can help animals navigate their worlds, and humans can learn to echolocate too. Many people with visual disabilities become experts in it, but even the most highly skilled person can't come close to what dolphins can do.
Echolocation is only one of the ways dolphins use sound in future episodes, we'll be coming back to Shark Bay to listen to their whistles and pops, sounds they use to communicate with each other and even to identify themselves. But now it's time for us to return to the terrestrial realm, to meet these mysterious creatures that are using sound in yet another fascinating way. We'll have more after this short break.
Hi, my name is Matt Hurley, and I've been a Threshold listener and donor since season one came out in 2017. I was also one of the first volunteer board members of the nonprofit organization that makes Threshold. Over the past seven plus years, I've had this unique first hand look at just
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I'm Dallas Taylor, host of 20,000 Hertz, a podcast that reveals the untold stories behind the sounds of our world. We've uncovered the incredible intelligence of talking parrots.
Basically, bird brain was a pejorative term, and here I had this bird that was doing the same types of tasks the primates.
We've investigated the bonding power of music.
There's an intimacy there in communicating through the medium of music that can be really a powerful force for bringing people together.
We've explored the subtle nuances of the human voice.
We have to remember that humans, over many hundreds of thousands of years of evolution, have become extremely attuned to the sounds of each other's voices.
And we've revealed why a famous composer wrote a piece made entirely of silence.
I think that's a really potentially quite useful and quite profound experience to have.
Subscribe to 20,000 Hertz right here in your podcast player. I'll meet you there. Dr. Rex Cocroft: So now we're hearing their mating signals.
Welcome back to Threshold, I'm Amy Martin, and we're back in the United States now with Dr Rex Cocroft and a group of wild animals. I'm not going to tell you what they are right away, just listen and guess. Dr. Rex Cocroft: Two or three different males. So cool. Here's a hint. These animals are much, much, much smaller than dolphins. They live all over the world, and millions of people walk by them every day as they make these sounds. But we don't
hear a thing. This sound is made by a treehopper, a teeny little insect about the size of a sunflower seed without the shell. It communicates by shaking its abdomen, which sends waves of vibrations through its legs and out into the stems and leaves of plants. Other tree hoppers can feel those vibrations with their legs, and they often respond with their own belly shakes. Dr. Rex Cocroft: And it doesn't look like they're doing anything
at all. There's stationary. If you're really close, you can see their abdomen moving when they signal. But otherwise it just looks like like nothing is happening. And ordinarily it also doesn't sound like anything is happening. These treehopper calls don't get broadcast out into the open air. It's not just that these insects are small and their calls are quiet. The vibrations they make don't leave
the body of the plant. We're only able to hear them now because Rex has hooked up a special microphone to the plants and connected it to some speakers. Dr. Rex Cocroft: If I turn the speaker down, you don't hear anything. And we're standing right next to this plant, and you could put your ears right next to me, you really don't hear anything. So these little insects are talking to each other through a secret world of sound called the vibroscape.
Instead of air or water, these acoustic waves are moving through the bodies of living plants. Dr. Rex Cocroft: It's like they take a different train, sec through acoustic space and put together sound in ways that we never thought to do. So what is going on here? How is it possible that these sounds are happening all around us, but we can't hear them? and how did Rex break the code? Well, it helps that he had an early interest in music like Lily Wang, and later he combined
that with a love of biology and animal communication. He studied frogs at first, but one day in the 1990s, Rex decided to find out if treehoppers had anything to say. Dr. Rex Cocroft: I just walked out onto a meadow near where I lived. I was at Cornell, so this was upstate New York, very beautiful place in the summer. I had a tape recorder. It was a cassette tape recorder and headphones. He found a goldenrod plant with some tree hoppers on it, and leaned a microphone right up against it.
Dr. Rex Cocroft: And immediately I heard these wonderful sounds. I'd never heard it before, this tiny insect, this beautiful song. And then I was hooked. I never looked back. It was a sound that I was completely unfamiliar with, and I could be confident that no human had ever heard that sound before, and that's still true with most, most insects that communicate through plants. You listen to them, and probably nobody's ever heard that sound before.
And that's basically just because we haven't been listening. We couldn't hear anything, so we thought there was nothing to hear. It's almost like the treehoppers turn the plants and their own bodies into musical instruments. That's partly what captivated Rex about these sounds the first time he heard them. Dr. Rex Cocroft: To me, it was totally different when I expected, because it had, it was like harmonically structured, and it was changing in pitch, and it was very exciting.
Before we knew anything about their sonic lives, treehoppers had attracted attention because of their appearance. Dr. Rex Cocroft: They look like miniature cicadas, and they have a kind of roof over their back that in many cases, is very elaborate and whose function we still don't really know in many cases. The treehoppers that Rex studies the most are called
thorn bugs, and they look like rose thorns that can walk. Other tree hoppers look like they have sand castles on their heads or bird droppings. Dr. Rex Cocroft: Others have what looks like a little Starship Enterprise in their back, a lot of interesting forms, and others, it's just a smooth roof. So treehoppers are kind of the quirky rock stars of the insect world pushing the boundaries of fashion and sound.
This next one might be my favorite. Its scientific name is potnia brevicornis, but I think of it as Rage Against the Machine. Again, this hidden world of acoustic signaling is called the vibroscape, and I love that term, but it also made me wonder, since waves of vibration are happening anywhere there's sound, isn't the vibroscape sort of everywhere? I put the question to Rex. Is there a sharply defined line between a sound and a vibration?
Because my understanding is that all sounds are vibrations. So why aren't all vibrations sounds? Dr. Rex Cocroft: They're very closely connected, and it depends on the sensory structures that you use to pick them up and how your nervous system then relays that information to your brain. We can experiment on ourselves in real time to
understand this. If you're playing this episode through a speaker in your house or your car right now, and you crank up the volume, you might be able to feel the music vibrating the floor or the steering wheel. If you're a person who hears airborne sound, you can also hear those waves as they hit your eardrums. The waves of vibration have the same source, the music, but they can be perceived through two different sensory systems.
Dr. Rex Cocroft: It's all the same thing. It's all mechanical energy that's propagating through an environment, whether it's a structure, whether it's the air, whether it's the water, but you have to have a different kind of sensor to pick it up. So for us, our vibration sensors are totally different from our ears and the information from those we feel it different. It goes to different parts of our brain, and so that's what makes it so different. For us. Dr. Rex Cocroft: For us, right. For us.
Our experience of these two waves of vibration is bifurcated into two different sensory systems, hearing and touch, but that's just a reflection of the way our bodies happen to be put together. Dr. Rex Cocroft: For other animals, they may be just two sides of the same coin, like the ones that I study, these insects with their six legs, and they have vibration sensors in their legs, but some of those vibration sensors also act as pickups for airborne sound. And I don't honestly know how they
tell the difference sometimes. How do they know if it's a sound or a vibration, if they're picking it up through their legs? And I'm not really sure the answer to that. Or maybe the whole question of what defines sound versus vibration only makes sense from within our own perceptual framework. Maybe if your senses of touch and hearing are more unified, there is no differentiation, really.
We're actually incredibly gifted listeners. You know that is inherent to being a human being. We have the capacity to listen. I think it's a categorization of the word "listen" that gets really confused.
Dame Evelyn Glennie is a world renowned percussionist and composer. She's also deaf. She doesn't hear airborne sound waves, but she says listening is available to everyone.
You know, we think about hearing, and
Evelyn grew up in rural northern Scotland, helping that's something that can be measured. That's something that, out on her family's farm, and she says the patience that you know, medically, we can see whether that person can hear a certain frequency at a certain volume. However, listening is farming requires gave her some of her first formative lessons not something that can be measured medically. Someone can be born deaf, but they can be amazing listeners. in listening.
Because listening is all about patience that I have learned over time. So you can't force a field to grow corn any quicker than it will grow the corn according to the season and the weather. You know, you can't dictate when a sheep will give birth to a lamb. It will just naturally give birth to a lamb as and when that time is right. You know, there are certain things that just need to happen naturally. And so
I think that is very much to do with listening. You know, is that we can control a certain amount, but ultimately, we also have to work in partnership with the existence that we're in, with the environment that we're in.
Evelyn had already exhibited a strong interest in and talent for music when she began to lose her hearing around the age of eight.
I realized that one aspect of the body was no longer working as it used to work.
But this change did not stop her development as a musician. In fact, it seems to have enhanced it. When she began studying percussion at age 12, her teacher suggested she take out her hearing aids and tune into other ways of sensing the music. That's when she started to learn how to listen with her whole body, to pay attention to the vibe escape.
It's simply the knowledge that sound is vibration, that is what sound is, and therefore our bodies are a resonating chamber. So if I'm playing a glockenspiel or cymbal or triangle or anything with high frequencies, it's more than likely going to touch the face and the upper part of the body. However, with low, low sounds, such as playing bass drum or timpani, or anything with a really low, resonant sound. Obviously the vibration is quite wider and bigger, and that will
reach a larger part of your lower part of the body. So you know, your tummy, your chest, down your legs, your feet, through the stage and so on.
Evelyn has developed her ability to feel differences in pitch, tone and musical color at a much subtler level than most people, and used those skills to become one of the most celebrated percussionists of all time. She composes for the concert hall, for films and for television, and she performs all over the world. She's won multiple Grammy Awards, the Polar Prize, and a long list of other honors. Clearly, she has a musical force in her that was not going to be denied no matter
what. But even though we're not all going to become musicians of Evelyn's caliber, she insists anyone can learn to sense sound as a whole body experience.
You know, the brain is an extraordinary thing, and it will re kind of jig itself in so many different ways. But it does need time. It really needs time.
It also needs courage and freedom to explore, and Evelyn has cultivated those qualities in herself, along with a beautiful sense of play. Despite all of her success and expertise, she positions herself as a learner. She greets an instrument or a piece of music like she's greeting a friend. She doesn't assume anything. She asks questions, starts a conversation.
I'm very thankful just to have a curious take on things, and I think that's really what it boils down to. If I'm picking up a, let's say, a waterphone or something, you know, the first thing I'll do is look at the object. What is it made of? Is it metal? Is it wood? Is it skin? Is it ceramic? Is it glass? Is it porcelain? What is it?
A waterphone looks like the mutant offspring of a pie pan and a hedgehog. It has a round base with spiky rods attached to it, which can be struck or bowed. The music you're hearing is from a video on Evelyn's YouTube channel called "Waterphone improvisation."
I look at the size of it. Is it hand held? Is it something that you have to sit to play? Is it something that you stand to play? Is it something that you use mallets to play or sticks to play and so on. So immediately, before I've even struck something, the whole body is involved. And how you can allow the body to be an extension of this object, so that there's no longer the player, the instrument, the audience, their music, the this, the that. So how is this body,
sort of merging into this instrument? And then I'm like a kid, so I don't go on the internet and find out how to play the instrument. I just say, Evelyn, what are you going to do with this instrument? So there's no boundaries, no expectations, nothing. So we as sound creators are sound artists. You know, we're painting sound into a space. So you just sort of begin to think, oh, yeah, that's a fat sound, because it's felt through your tummy or your lower part.
Oh, that's a much thinner sound, or that's a weak sound, or, oh, this is as far as I can go dynamically without maybe causing harm to the instrument. These are the different objects I can use. And bit by bit, you build up your kind of color
palette. And so when you're looking at an instrument and engaging with that instrument, you're basically finding out all of the sign colors you possibly can in the environment that you're in that that particular instrument can produce through the imagination that you have and that you're willing to engage with. And that is that.
Evelyn has become famous as a maker of sounds, but she says her primary purpose is to teach the world to listen. In fact, she created a foundation to advance that mission.
Listening is about being in the here and now. It's about living each day and taking the time to experience what is right in front of you. So it's kind of stripping down all of the complications, releasing all of the baggage that's on our shoulders, all of the expectations. It is just simply being and that's very liberating.
I wanted to expand the boundaries of my own listening abilities and see if I could tap into the secret treehopper communication channel that Rex had told me about. So I bought a small contact microphone and attached it to some plants, a lot of plants, and mostly I heard wind and plant stems bumping into each other. But I got better with practice, and one day in a park in Iowa City, the magic happened. I couldn't see who was making this noise or where it was, but
somebody was talking and kind of humming. I sent this recording to Rex Cocroft, and he said it was definitely something in the cicada group, probably a leafhopper, but he couldn't say for sure which one. He said it wasn't a sound he had recorded, and chances were no one else had heard or recorded it either, which felt pretty extraordinary. It's not very often that I can say I might have recorded a sound that no other human has ever heard, and now you've heard it too.
We don't know what it's like to be a treehopper hearing or hear feeling the call of another treehopper through a plant. Just like with the dolphins, we can't get inside their experience. We can get closer to guessing what our fellow humans are experiencing, but even then, we can't really know. Some people feel vibrations very sensitively. Other people hear a huge range of airborne sound, or none at all, and whatever we're hearing and feeling right now, that experience is bound to
change over time, often in ways we can't control. Sound is ephemeral and ever changing, and so is our experience of it. So you know that Christmas carol that asks, do you hear what I hear? Well, now I know that the answer is probably, no, I don't. Or maybe kind of sometimes? but that difference is actually what
connects us. No one person or even one species can hear everything, but together, we are a planetary ensemble of listeners, each of us making our own entirely unique contributions, the treehoppers and the spiders, the dolphins and the percussionists, the corals and the fishes and you and me. This episode of Threshold was written, reported and produced by me, Amy Martin, with help from Erika Janik and Sam Moore. Music by Todd Sickafoose, post production by Alan Douches. Fact
checking by Sam Moore. Special thanks to Stephanie King for some of the dolphin sounds you heard in this episode, to Rex Cocroft for the use of his treehopper recordings, and to Evelyn Glennie for the use of her music. I highly recommend that you check out Evelyn's YouTube channel and watch her do the waterphone improvisation we played or any of her other videos there. Just search for Dame Evelyn Glennie on YouTube, or you can find a link on our website or in the show notes.
Threshold is made by Auricle Productions, a non profit organization powered by listener donations. Deneen Weiske is our Executive Director. Learn more at thresholdpodcast.org.