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[Music start]

From Defacto Sound, you’re listening to Twenty Thousand Hertz. The stories behind the world’s most recognizable and interesting sounds. I’m Dallas Taylor.

This is the story behind our hearing and what happens when it goes away.

[club music fading to silence]

Even a small amount of hearing loss can significantly impact a person. Almost forty million American adults, that’s fifteen percent, have difficulty hearing. And it gets worse the older you get. And right now, the world is louder than it’s ever been before.

Lindsay: Hearing loss for the most part tends to be a gradual thing for people as they age.

That’s Audiologist, Lindsay Prusick.

Lindsay: When people have hearing loss, largely, it's an invisible thing. You don't see it, but it has such a profound impact on people's ability to connect, communicate, even ultimately their quality of life. There are a lot of people who are born with hearing loss and it can be as a result of genetics, syndromes, things acquired through when a mother gives birth to a baby, various viruses, that type of thing.

Because it is so invisible, many people don’t think about hearing loss very much at all.

Lindsay: Really, in general, for the majority of people with hearing loss, it's a very gradual thing. People start to notice over time, "Oh gosh, it's hard to understand speech. Things sound muffled. People sound like they're mumbling," or just the quality of sound begins to decrease. [music decrease SFX]

This is a good thing to remember when you’re talking to older people...or really anyone who asks you to repeat yourself. You yourself can work to prevent hearing loss or additional hearing loss. But, it’s harder today than ever before.

Lindsay: We're constantly putting things in our ears and listening to sound. We're walking around with our smart phones that have now become basically our television [HBO SFX], our podcast source…[20K theme song, record scratch]

Hey, don’t blame me, I’m not controlling your volume!

Lindsay: Our music source, [music start] and we're placing ear buds into our ears and maybe you're getting on the subway [subway SFX] or you're on an airplane [airplane cabin SFX] or you're just in a noisy environment. So what do you do? You crank up that volume. That can be a very dangerous thing.

A great rule of thumb is if somebody is three feet away from you, and they're talking to you, and you can't hear them, the sound is too loud. And you should turn the volume down.

There are all sorts of things in our environment that can threaten our ears.

Lindsay: Try to think about the last time you were in a noisy situation, so a concert [concert SFX], maybe you mowed your lawn [lawn mower SFX], maybe you even just blow dried your hair [hair dryer SFX]. It seemed really loud at first and it's not as loud and that's because people experience a temporary shift in their hearing. They’re not nearly as sensitive to those sounds anymore. Let's say you're at a concert and you run to the concession stands. [begin muffling Lindsey] The cashier begins to talk to you and you realize they sound muffled.

Then maybe you hear a slight buzz or hum [buzz SFX] in your ears. These are all things you can notice when you're in the moment, but most people notice it the next day. I always refer to it as a noise hangover. It's typically your hearing is muffled or it's not as sensitive. You could even feel fatigued. Literally, just more tired than usual and you could have a headache. And these symptoms can last a day, they can last a couple days depending on how often you’ve exposed yourself to extreme levels of noise, you can even find that some of the symptoms go away, but others persist.

Over time the ears can take a beating and they may go back to normal, but the reality of it is anytime you exposure yourself to dangerous levels of sound, it does do damage to the hearing system.

One clear symptom of hearing damage is a ringing in the ears called tinnitus.

Lindsay: Tinnitus is the perception of sound either in one ear, both ears, or just in your head, without an actual sound occurring in the environment. It can be described in many ways. I'd say one of the most common is people will say, "I have a high pitched ringing" [high pitched ringing SFX]. They can express it as sounding like crickets [crickets SFX], buzzing [buzzing SFX], a tea kettle going off [tea kettle SFX]. There's all sorts of descriptions for it. It can be intermittent, meaning it happens at different times of the day, or it can be constant [tea kettle and ringing SFX], it is literally always there. A majority of the population when they experience Tinnitus, they find that they'll hear it and it'll go away. There are a lot of people that are highly, highly impacted.

Do you have tinnitus or other signs of hearing damage? Even if you don’t, I want you to try something with me.

For this part of the show, if you can, find a quiet space where you can concentrate for a few minutes. If you’re driving or something, just carry on. You can come back to this later.

Okay, welcome back.

Now set the volume at a comfortable level [mic check]. All set? Okay. The healthy hearing critical range is between 500 Hertz and 4,000 Hertz.

A Hertz is a measure of frequency and vibration. Imagine a speaker cone: It starts in the resting position, pushes outward, pulls back inward and then goes back to the resting position. One Hertz means this cycle would happen over the course of exactly one second. But we as humans can’t start to detect that sound until the speak is going through that cycle around 20 times a second.

That’s 20 Hertz, and it’s extremely low...at a high volume you’d be more likely to feel it rather than hear it, but that’s the threshold of where hearing begins. As we speed that speaker up, the pitch raises. Humans can theoretically hear all the way up to around 20,000 Hertz, but, you probably haven’t hear that sound since you were a kid. More on that shortly.

Now I’m going to play sounds in the critical range.

Here’s 500Hz [example]

Here’s 1,000Hz [example]

Here’s 2,000 Hz [example]

And this is 4,000Hz [example]

Now, this is in no way scientific. Your results will vary based on what type of headphones or speakers you’re using, where you’re listening, and any EQ settings you might have changed on your device. Still for most devices in most places all of those tones should have been clearly audible. So, if you struggled to hear any of those tones or couldn’t hear them at all, please go to a professional to get your hearing checked.

Now, just for fun, we’re going to go a little further. Everyone with average hearing should be able to hear 8,000 Hertz.

[example]

But, as we get older, our hearing range naturally diminishes to where we lose sounds in the top of our range. There are particular ranges that people over a certain age are not likely to hear. We’re going to play some of those now.

The first one, 12,000 Hz, is usually only audible to people under the age of 50.

[example]

And here’s 15,000 Hz, for people under 30…

[example]

And then 17,000 Hz, which only people under 18 should be able to hear.

[example]

Then there’s 20,000 Hz, here this show gets its name, it’s the highest possible sound that any human can hear.

Check it out...if you can hear it.

[example]

And finally, we’ll play a full sweep of the entire range of human hearing which is 20 Hertz all the way up to 20,000 Hertz.

Again, take all of this with a grain a salt because all listening devices vary. For example, if you’re listening in earbuds, you’re not going to hear anything in the low frequency ranges, but if you have a subwoofer in your car you might.

Now...

This is 20 Hertz [example] ...here’s 100 [example] ...200… [example]

this is 500 [example] ...1,000 [example] ...2,000 [example] ...4,000 [example] ...8,000 [example] ...12,000 [example] ...15,000 [example]. ..18,000… [example]

[example] and that was 20,000.

Based on your age, it may have sounded like we just stopped the test at some point. We all hear differently, and in a minute I’ll explain how some businesses have taken advantage of this as well as speak with someone who has experienced extreme hearing loss.

[music out]

MIDROLL

[music in]

As you now know, young people can typically hear higher frequencies than older people...and businesses have actually taken advantage of this. For instance, it’s been reported that businesses have blasted 17,000 Hertz tones in front of stores to keep kids from loitering. Most adults can’t hear it, but kids, are repelled by it.

Then, of course, kids figured out a way to use this tone to their advantage and started setting it as a text notification on their phones. This way they can get messages in class without the teacher catching on.

Just because you can’t hear something doesn’t mean it isn’t there. And nobody knows that better than Shaheem Sanchez.

Shaheem: I wasn’t born deaf. I lost my hearing when I was four.

Because of a bad nerve in his inner ears, now one ear is completely deaf. In the other, he uses a hearing aid.

Since he lost his hearing at age four, he has some foundation for hearing speech. This is part of why he’s able to speak as well as he can. The other part is that he can still hear some things.

Shaheem: I can hear with a hearing aid but not everything. I can hear a dog barking [dog bark]. A car sound [car SFX]. I can hear people talk [people talking SFX] but I don’t know what they’re saying. All I hear is mumbling like bu-bu-bu-bu-bu. That’s all I hear.

He can read lips, but he didn’t learn sign language until high school.

Shaheem: I grew up speaking. That’s why now, I speak clear.

But even though Shaheem’s able to voice for himself, he still endured bullying growing up.

Shaheem: People always used to judge me. Why you talk like that? You can’t hear yourself. They call me all kinds of names. But I feel comfortable now. I’m more comfortable.

But dancing was something that he always felt comfortable with.

Shaheem: I started dancing when I was 11. It’s what I love to do. I started dancing because my dad he also a dancer. He was killed before I was born so I never met him. So my family told me about him. I started to feel inspired. And then I started teaching myself how to dance.

But I didn’t hear so I only watched body language. Sign language is like body language, so that’s how I’m so good at that.

About ten years ago, when he was in high school, Shaheem was dancing on the street when he was approached by a dance instructor. That’s when he started taking formal lessons.

Shaheem: I have my own style but I’m learning different styles. Like ballet, jazz, hip hop, breakdancing, salsa, a lot of different styles.

But his favorite style?

Shaheem: I’m really into, like, R&B songs. I like dubstep. I also like hip hop, too. I feel the beat. The vibration. Most of the time.

He listens to songs by putting his hand on the speaker and feeling the beat. He also watches music videos with the captions on. It’s a painstaking process...

Shaheem: Study. Memorize. Listen to it over, over, over, and over. So I’m memorizing it. It’s not easy. Normally takes me, like, three weeks. I know a lot of songs. It’s crazy.

Shaheem’s the only one in his immediate family who’s deaf, but he isn’t the only dancer.

Shaheem: My brother, he looks up to me. I taught him how to dance. He picked up fast. I don’t know how he do it. He got better and better and better and better. Now, he better than me.

Shaheem’s brother, who goes by the name Lil Kida, got so good, he actually won a season of the TV show “So You Think You Can Dance.”

But Shaheem didn’t just teach his brother to dance…he taught him his drive too.

Shaheem: If you love to do it, put your heart into it. Never give up. No matter what. Deaf or not, you still can do it. Anything is possible.

A lot of hearing people just don’t know enough about what it’s like to be deaf. He knows visibility is crucial to understanding and has taken on raising awareness about the deaf community like it’s his job.

Shaheem: I want to show the world that deaf people can do anything equal to everyone. I want people to know that we may be different, but we do the things you can do. We can drive. We can read. We can learn. We can listen to music. We can do anything.

Our society is based around having all of your senses. And hearing is something a lot of us take for granted even though we shouldn't.

Hearing is fragile. Fleeting, even.

If you have it, protect it. And if you don’t, don’t apologize for it.

Whatever your situation, try to keep in mind that you’ll never know what other people’s experiences are unless you put in the work to find out.

Twenty Thousand Hertz is presented by Defacto Sound a sound design team dedicated to making television, film and games sound insanely cool. Find out more at defactosound.com.This episode was produced by Miellyn Fitzwater Barrows and me. With help from Sam Schneble. It was sound designed and mixed by Nick Spradlin.

Thanks to audiologist Lindsay Prusick and to Shaheem Sanchez. You can see videos of Shaheem’s dancing on his instagram page at instagram.com/shaaheem. We will have a link to this and his Youtube page in the show notes.

We’d also like to thank Malonda Hutson and Susan Thompson-Gaines for their advice on the topic.

The music you’ve hearing is from Musicbed. They represent more than 650 great artists ranging from indie rock and hip hop to classical and electronic. Head over to music.20k.org to hear our exclusive playlist.

Finally, please tell your friends about the show, and connect with us on social!

You’ll find all of the links I’ve mentioned in the show description.

Thanks for listening.