Every other Friday, the Outside/In team here at NHPR answers listener questions about science and the natural world. This week's question comes from Shaina in Montpelier, Vermont, who just got a pair of bone conduction headphones.
"I'm finding that I have to crank up the volume, and I'm wondering if bone conduction is better or worse for hearing loss than regular headphones."
Producer Felix Poon reports.
This transcript has been lightly edited for clarity.
Felix Poon: There’s a story that when Beethoven started losing his hearing he attached a wooden drumstick to his piano and held the other end of it between his teeth so he could hear himself play. The story might be apocryphal, but the concept is valid. It’s called bone conduction. And they make bone conduction headphones these days, so we don’t have to resort to biting on drumsticks anymore. To understand how they work, I spoke to Rick Neitzel. Rick is a researcher at the University of Michigan studying the impact of noise exposure on human health.
Rick Neitzel: Bone conduction headphones essentially bypass the outer ear and and go directly into the inner ear by transmitting sound waves as vibrations through our skull.
Felix Poon: That’s right, the skull. Traditional earbuds sit just inside the ear canal of the outer ear. Bone conduction headphones are designed to press on your cheekbones, in front of your ears. They work by sending vibrations along your cheekbone directly to the part of your inner ear called the cochlea. The cochlea is an extraordinarily sensitive structure, and is especially vulnerable to loud noises. So, why choose bone-conduction headphones? They allow you to keep your ears free so you can hear the world around you. Rick owns a pair himself.
Rick Neitzel: I use them to go exercise. I like to be able to monitor my surroundings and make sure I’m not going to be run over by a car coming up from behind me.
Felix Poon: But there are a couple features of bone conduction headphones which might tempt you to turn up the volume. For one, Rick says the sound just isn’t as good, especially when it comes to low frequencies.
Rick Neitzel: So the bass just isn't going to be as rich and powerful as it is with an earbud or headphone.
Felix Poon: Another issue with bone conduction headphones can come up in loud environments, like a subway, for example. The intent is to leave your ears free, but that of course means—
Rick Neitzel: They are not going to protect you from that outside sound and, in fact, you're going to need to listen at a higher volume to overcome that sound.
Felix Poon: A higher volume that goes directly to your inner ear, that super sensitive cochlea. So, yes, bone conduction headphones can definitely cause hearing loss. So what’s a concerned listener to do? Rick has some tips. First, your surroundings matter. Rick says that it’s safest to use bone conduction headphones in quieter places, like on a trail when you want to hear the birds for example. But if you’re often in noisy environments, Rick says it might be worth investing in a pair of noise canceling headphones. That way you can keep the volume low, but still have a good listening experience. And second, look at the settings on your device. Most smartphones have built-in features to limit or reduce loud sounds from your phone. And there are also built-in apps that can track your listening habits and alert you if you’re approaching unsafe volumes over time. And then Rick has one final tip, no matter what type of headphones you use.
Rick Neitzel: Don’t listen all day long. It's important for your ears to get a break.
Felix Poon: Because even Beethoven needed a break from his drum sticks every once in a while.
