Headphones are so widespread and generally understood by the average individual. However, the average person knows surprisingly little about bone conduction headphones and how they work. So, how do bone conduction headphones work?
The most straightforward answer is that bone conduction headphones use vibrations against bones to pass sound into the cochlea. These work differently than regular earphones as instead of passing the vibrations of sound through the air; they’re passed through the bone. Passing the waves through the bone causes them to miss the eardrums entirely; thus, they actually have the ability to get around some hearing disabilities.
Of course, this is only the simplest way to explain how bone conduction headphones work. This technology is relatively looked over in the age of wireless headphones but has incredibly fascinating uses and innovation.
This technology started as early as the 1500s and has a history nearly as interesting as the science behind it.
How Do These Vibrations Get to the Cochlea?
Sound travels in waves through the air, much like light, but unlike light, sound can travel through much denser objects.
This is how you can hear the music from a neighbor’s room, and feel your walls shaking, but not see their light on through the wall.
Your ear picks up these waves through vibrating to pass the sound along inside, often starting with the eardrum.
The eardrum is a thin flap of skin that vibrates when sound waves hit it, and it causes other organs in the ear to vibrate. However, an essential part of the hearing is those vibrations being picked up by the cochlea.
When the eardrum and other organs in your ear begin to vibrate, the cochlea starts receiving all of the sound vibrations and passes them along to the stereocilia. From there, the stereocilia transform this input into signals they pass along to the brain.
In short, the vibrations from the eardrum pass throughout the ear, and in this relationship, it’s ultimately the signals the cochlea picks up that get sent to the brain.
How does this happen without the vibrations of the eardrums? This is where bone conduction comes in.
How Does Bone Conduction Skip the Eardrum?
This is a lot simpler with the knowledge above of how the inner ear works. The eardrum is often where the vibrations start throughout your other little internal ear organs, but it isn’t necessary to conduct those vibrations. However, without its input, all of the bones and organs inside your ear would remain static.
How do you bypass the need for the eardrum to start the other organs and bones vibrating? Conducting the vibrations through bone instead of the eardrum causes it to avoid that need, triggering the vibrations in your ear’s inner organs by passing them through your skull.
These vibrations would work the same as the ones that are started by the eardrum because the cochlea does not know the difference.
Just like the process of hearing that is started through your eardrum, the cochlea sends these vibrations through the channels to your brain. Your brain registers these sounds the same as they would through a traditional headphone.
There is a common misconception that bone conduction headphones are entirely silent. This isn’t true; these headphones are still audible but significantly less audible than the traditional earbuds are.
The difference is, they’re designed to send the sound waves through your skull instead of through the air.
How Did Bone Conduction Start?
The idea of bone conduction technology isn’t new, it was discovered as early as the 1500s, though there is reason to believe you can trace it back further.
Gerolamo Cardano, physician, philosopher, and mathematician, realized that you could hear through a rod and spear when you placed them between your teeth.
Even though he figured this out, the actual use of this for deaf and hearing-impaired individuals didn’t start until later.
Bone Conduction in Hearing Aids
Cardano’s findings were controversial at the time they were published, so it wasn’t for another several hundred years that it came back into the public attention.
Some people theorize that this idea, the rod between the teeth, is how Beethoven could faintly hear what he was composing.
The theory proposes that he might have taken one end of a rod between his teeth and the other against the piano.
It wasn’t until the 1940’s that the study of audiology became recognized as a science. This helped bone conduction be put into practice to help with diagnosing hearing disorders and supporting the hearing-impaired.
This led to the introduction of bone-anchored hearing aids (BAHA hearing aids) in the 1970s. These implants allowed the user to hear through the bone conduction, and thus if the problem were their eardrum, it would help them hear without it.
Is Bone Conduction Just for the Hearing Impaired?
This technology has been an absolute game-changer in the hearing impaired and deaf communities, but it isn’t an exclusive technology.
The military has long used bone conducting technology, and it’s been found incredibly useful for the athletic community.
When running, cycling, and being outdoors working out, having a bone conduction headphone instead of a traditional earphone allows you to hear passing cars and lets them be more aware of their surroundings.
There are limitless applications of the technology, however. They were used in Google Glass, education, law enforcement, construction, and even in scuba diving.
Thanks to their open ear design, they’re considered comfortable to wear as well, which is just another addition to the list of their many benefits.
Can Bone Conduction Headphones Damage Hearing?
Yes. Simply put, they are equally as “dangerous” as average headphones. Some people claim that bone conduction headphones don’t risk damage to the ear because they bypass the eardrum.
Though this is true, the eardrum is not what you need to be concerned about. If you’re listening to music for extended periods at unnecessarily loud volumes, what you need to worry about is the cochlear taking damage.
This is true for both bone conduction headphones and conventional headphones, and neither is necessarily more dangerous than the other. Both of them can cause damage to the cochlear if you’re careless with volume and duration of use.
What is the Audio Quality of Bone Conduction?
Truth be told, they don’t sound as clear as traditional headphones. It’s neither good nor bad, just different.
Unlike conventional headphones, they sound a little muffled and thus don’t give the noise-canceling crisp edges that many modern headphones sport.
They do have their uses, and when you want to be more aware of your surroundings while you’re listening to your music, these are still a preferred option for many.
They can be good for hands-free calls, and for machinery workers outside of the needs of the hearing impaired.
If the quality of the audio is a priority, and you’re expecting it to be equivalent to regular headphones, you will be disappointed.
Final Thoughts on How Do Bone Conduction Headphones Work
Bone conduction headphones are by no means new, but the technology is incredibly useful in both the diagnosis of hearing impairments and a solution for them.
Thanks to the invention of the technology, there is another- oftentimes safer- solution for runners and bikers both.
Though they still pose the same “threat” to the cochlea as the traditional headphones, they leave the ear open for other input while remaining quiet.
All in all, this technology was able to help bypass the eardrum for the usage of those with hearing impairments, and everyday users who need to be able to hear both the audio of the headphone and the world around them simultaneously.