How Bone Conduction Headphones Work (and When to Use Them)
I love my bone conduction headphones. I wear them while running to hear approaching traffic. They’re also great for noisy environments where I have to use earplugs—since the headphones don’t require my ear canal to be open, I can use earplugs and still hear music transmitted via bone conduction. But there’s no denying that bone conduction headphones offer a completely different experience than traditional in-ear headphones. So what exactly is this strange technology, and what are its drawbacks? Let me explain.
How bone conduction works
Normally, when we hear a sound from the space around us, sound waves travel through the air until they reach our eardrum, located inside the ear canal. The eardrum vibrates in time with the music—or rather, in time with the frequency of the sound—and transmits this vibration to tiny bones located in the middle ear.
To understand this explanation, you only need to know one aspect of hearing. But if you’re curious, after the vibrations reach these tiny bones, they’re transmitted to the inner ear. There, in the cochlea, the sound waves are converted into signals sent to our brain, and then processed to shape our perception of sound. However, all of that is beyond the scope of this article. We’re only interested in how the vibrations travel from the headphones to the middle ear.
There’s another way to vibrate the bones of the middle ear: you can do it directly, by sending vibrations directly through your head. Legend has it that Beethoven bit his baton and pressed it against the piano to “hear” through his teeth. You can try this right now with any old headphones: turn on some music and place the earpiece speaker against your tooth. You’ll hear music. Amazing, right? You can even buy unusual candies that play music through your teeth—bite into one, and you’ll hear a melody.
We constantly hear sounds transmitted through bone tissue. Every time you speak, you hear your own voice through bone (and soft tissue) conduction and through the air. (This is probably why your recorded voice sounds so unusual compared to what you’re used to hearing when you speak.) Plug your ears with your fingers and speak out loud, and you’ll hear only the portion of the sound transmitted through bone tissue.
Bone conduction headphones exploit this phenomenon. Like all headphones, they have tiny speakers. But instead of directing these tiny speakers into our ear canals to vibrate the air and then the eardrums, headphones are designed to press their tiny speakers against bone—usually the cheekbone just in front of the ear. Technically, they also conduct sound through soft tissues like skin, muscle, and fat, but bone transmits sound very well, which is where this technology gets its name.
Do Shokz and other bone conduction headphones actually transmit sound through bone?
Yes, they work through actual bone conduction, but it’s not just bone conduction. Some of the sound is transmitted through the air as well. People don’t always believe this. I’ve seen threads on Reddit where people debate whether bone conduction is a myth, so here are two experiments you can try with bone conduction headphones to understand both sides of the story.
First, put them on as usual. The small speakers will be located on the bony protrusion just in front of your ear. Turn on some music. Now, gently move the speakers away from your head so they’re no longer in contact with your head. Yes , you’ll still hear the music, but it will sound muffled and quieter than when you were wearing them normally. This shows that bone conduction does transmit most of the sound you hear.
Now put them back on as usual, but plug your ears with your fingers (or, if you prefer, with comfortable earplugs). The sound will be different—I’d describe it as slightly deeper. It even seems louder. Headphones definitely don’t need air to reach your eardrums to transmit sound. This shows that with bone conduction alone , you get most of the sound, but not all of it, from the headphones.
Some headphones intentionally use a hybrid approach. The Shokz OpenRun Pro 2 headphones, in addition to the drivers designed for bone conduction, feature an additional set of drivers for airborne sound transmission. This typically provides a better frequency balance and, therefore, better sound quality than headphones using bone conduction alone.
Is bone conduction safe for your ears?
Bone conduction headphones are no better or worse for your ears than traditional headphones, because ultimately the same thing happens in both cases: your cochlea ( the part of the ear that is damaged in the most common types of hearing loss) still perceives vibrations. Bone conduction headphones that are too loud are just as harmful to your ears as regular headphones that are too loud.
As I noted above, there is one way bone conduction headphones can be better for your ears: if you are in a noisy environment, you can use earplugs to protect your ears from the loud sounds around you, and bone conduction headphones to play music and fill the silence.
This summer, I started using a combination of earplugs and headphones when I was training outdoors a lot near a noisy air conditioner (I also realized that the sound of a barbell dropping is also quite loud, as dropping a barbell is a common part of Olympic weightlifting). So I bought Loop earplugs and found that not only could I hear music through my Aftershokz Aeropex Mini (an older version of the current Shokz OpenRun Mini ), but I could also turn the volume down to near-minus and still hear it perfectly. Overall, my ears are exposed to much less noise, so it’s a win-win.
What are the disadvantages of bone conduction headphones?
As we discussed above, there are no health or safety disadvantages, but you won’t get perfect sound quality from bone conduction headphones. Some are better than others, and you should always read reviews and try them out in person if you want to base your purchase decision on sound quality. But overall, the advantage of bone conduction headphones is also their disadvantage: since Shokz and similar models don’t block out ambient sound, the sound reaching your ear is a mixture of the music you’re listening to and ambient noise.
When I use bone conduction headphones and earplugs, the sound quality also leaves much to be desired. Just as your voice sounds different when you have plugs in your ears, the sound from bone conduction headphones with earplugs doesn’t quite match what you’d hear through high-quality headphones.
Personally, I think these minor drawbacks are offset by the advantages of bone conduction headphones. I don’t need to listen to podcasts in crystal-clear sound while running; I just need to understand what the hosts are saying while also listening for approaching cars. When I do want to listen to high-quality music, I do it at home, with good noise-canceling headphones .