How Bone Conduction Headphones Work (and When You Should Use Them)
I like bone conduction headphones. I wear them when I run so I can hear approaching traffic. I also love them for noisy environments where I put earplugs in. Because headphones do not require opening the ear canal, I can use earplugs and still hear bone conduction music. So what’s going on with this strange technology and what are its downsides? I’ll explain.
How does bone conduction work?
Normally, when we hear a sound from something around us, the sound waves travel through the air until they reach the eardrum, located inside the ear canal. The eardrum vibrates to the beat of the music (actually, the frequency of the sound) and transmits this vibration to tiny bones located in what is called the middle ear.
(From there, the vibrations are transmitted to the inner ear, including the cochlea, where they are converted into signals sent to our brains and then processed into our perception of sound. However, all of this is beyond the scope of this article. We’re just wondering how the vibrations from our headphones travel to the middle ear.)
However, there is another way to vibrate the middle ear bones: you can do it directly by sending vibrations directly through your head. According to legend, Beethoven bit his baton and brought it to the piano to “hear” through his teeth. You can try this right now with any old headphones: turn on some music and hold the speaker of the headphone to your tooth. You will hear music. Wild, right?
In fact, we constantly hear sounds conducted by bone tissue. Every time you speak, you hear your own voice through bone (and soft tissue) conduction and through the air. (This may be why your recorded voice sounds so different from what you’re used to hearing when you speak.) Put your fingers in your ears and speak out loud, and you’ll only hear the bone conduction part.
Bone conduction headphones take advantage of this phenomenon. Like all headphones, they have tiny speakers. But instead of pointing those little speakers into our ear canals to vibrate the air and then into our eardrums, headphones are designed to press their little speakers against a bone—usually the cheekbone just in front of the ear. Technically they also conduct sound through soft tissue such as skin, muscle and fat, but bones do a really good job and are what the technology is named after.
Do Shokz and other bone conduction headphones actually conduct sound through bone?
Yes, they work through actual bone conduction, but not just through bone conduction. Some sound is also transmitted through the air.
Since people don’t always believe this (I came across a few threads on Reddit where people were arguing about whether bone conduction is bullshit), here are two little experiments you can do with bone conduction headphones to see what’s going on.
First, wear them as usual. Small speakers will be located on the bone right in front of your ear. Turn on the music. Enjoy. Now carefully move the speakers away from your head so that they are no longer touching. Yes , you will still hear the music. But they will be quieter and quieter than when you would normally wear them.
Now put them back on as usual, but plug your ears with your fingers (or comfortable earplugs if you prefer). The sound will be different – a little deeper, that’s how I would describe it, but I’m not an audiophile. It seems like it’s getting louder. Headphones definitely don’t require air access to your eardrums to transmit sound.
Is bone conduction safe for your ears?
Bone conduction is no better or worse for your ears than traditional headphones, because ultimately the same thing happens in each case. Your cochlea ( the part of the ear that is damaged in the most common types of hearing loss) still senses vibrations anyway. Bone conduction headphones that are too loud are bad for you, just like regular headphones that are too loud.
There is one way to make bone conduction headphones healthier for your ears, as I hinted at above. If you are in a noisy environment, you can wear earplugs to protect your ears from loud sounds around you, as well as bone conduction headphones to listen to some music and fill the silence.
This summer I started wearing a set of earplugs and headphones while doing a lot of outdoor training near loud air conditioning, and also realized that the sound of a barbell falling is actually pretty damn loud too (barbells falling is a routine part of Olympic weightlifting). So, I bought Loop earplugs and found that not only could I hear music through the Aftershokz Aeropex Mini (an older version of what is now called the Shokz OpenRun Mini ), but I could turn the volume down almost to minimum and still hear it fine. My ears are exposed to much less noise overall, so it’s a win-win.
What are the disadvantages of bone conduction headphones?
There are no health or safety concerns (as we discussed above), but you won’t get flawless audio quality through bone conduction headphones.
Some are better than others, and you should always check reviews and try the headphones in person if you want to make a purchasing decision based on sound quality. But in general, the advantages of bone conduction headphones are also their disadvantages. Because the Shokz and its ilk don’t block out ambient sounds, the sound that reaches your ear is a mixture of the music you’re specifically playing and the noises of the world around you.
When I wear Aftershokz with earplugs, I don’t get good sound quality either. Just as your voice sounds different when your ears are plugged, the sound combination of bone conduction and earplugs isn’t quite the same as what you hear through a good quality pair of headphones.
Personally, I think these minor drawbacks are balanced out by the other benefits of bone conduction headphones. I don’t need to listen to podcasts with crystal clear audio while running, I just need to be able to listen while still being able to hear what’s going on around me. When I want to listen to music in high quality, I do it at home with good noise-canceling headphones .