Despite bone conduction headphones only becoming mainstream in the last decade, the technology behind them is ancient, with some experts claiming its use as far back as 500 BC. The great composer Ludwig Von Beethoven used a form of bone conduction to “hear” his compositions. But what is this incredible technology? How do bone conduction headphones work?
Bone conduction headphones work by passing vibrations directly into your jaw or skull. This bypasses the outer ear and the eardrum entirely, but you can still hear the sound because your cochlear fluids still pick it up, so your brain can still interpret it as sound, causing you to hear.
Most people have never heard of bone conduction, and the concept seems almost supernatural to them. How can you hear without hearing? That’s why I’m often asked about the meaning of the term “bone conduction” and how the headphones work. Let’s go into more detail on what sound is and what that means for bone conduction.
The Technical Basis For Bone Conduction: What Is Sound?
To clearly understand bone conduction, we must first understand sound itself.
Sound is really just a series of vibrations passing through the air. Speakers and regular headphones work by taking the electrical signals from our phones, radios, or TVs and passing them through a vibrating membrane, which passes the vibrations into the air particles around us.
These vibrating air particles pass through our outer ears and are picked up by our eardrums, which repeat the vibrations along to our cochlea, where our brains can pick them up and convert them into what we know as sound. This is called “air conduction” since airwaves carry the sound vibrations to our ears.
How Bone Conduction Works
Have you ever noticed how loud it can be when you’re chewing? Especially if it’s something crunchy. And yet, despite how loud it is to you, nobody else in the room will seem bothered. That’s because you hear the crunch through bone conduction. It’s also why your voice sounds different to you than it does to other people.
Bone conduction is a way to pass sound vibrations through your bones instead of through the air. Chewing, for example, vibrates through your jawbone, which has direct access to your inner ear and the cochlear fluid that helps to convert the vibrations into signals that your brain can interpret.
Bone conduction headphones use that same principle to convey sound to your ears.
How Bone Conduction Headphones Work
Bone conduction headphones are based on hearing aid technology that enables people with outer-ear disabilities to hear by passing vibrations directly into their inner ears.
Whereas standard air conduction earphones and headphones use regular speakers that create vibrations in airways to travel to your ears conventionally, bone conduction headphones have devices called transducers.
The headphones fit snugly against your scalp and press the transducers into one of the bones in your head near your ears (usually the cheekbones or jawbone). Different models use different bones but are always located somewhere close to your inner ears. The transducers then vibrate against the bones, and the vibrations pass through them into your cochlea, where your brain interprets them.
Can Sound Travel Clearly Through Solid Material, Like Bones?
One of the concerns that people often have about bone conduction headphones is that they won’t work very well because sound can’t travel clearly through solid material. Though there is some truth to that, it’s not always the case.
Anyone who’s ever been in a multi-level building with wooden floors will know that whenever people move upstairs, you can hear it downstairs. The same applies to rooms separated by wooden walls; many sounds from one room will travel through to the next, especially if you hold your ear against the wall.
Sound vibrations can travel very well through certain types of solid materials. Bones are dense but still porous enough to let the vibrations travel through very effectively.
How Well Do Bone Conduction Headphones Work?
Most people who try bone conduction headphones for the first time are pretty surprised by the quality and volume of the sound unless their expectations are too high, to begin with.
Our brains don’t differentiate between sounds that come from our eardrums and those that travel through bones. If it’s a vibration that passes anywhere near our ears, we will pick it up. This means that you can hear music as clearly through bone conduction headphones as you would through any other earphones, as long as you keep a few points in mind:
- The sound may have a lower volume. Standard earphones and headphones block out external noise while trapping most of the sound inside our ears, increasing their volume.
In contrast, bone conduction headphones leave your ears open to ambient noise in your surroundings, which is one of their primary benefits since you can remain aware of your environment. Unfortunately, this means the sound from your bone conduction headphones is often drowned out by ambient noise unless you wear earplugs.
- The quality of the sound may not be good enough for audiophiles. Due in part to the same volume-related issues, it seems that some sound frequencies don’t travel as well through bone conduction as others. Headphone manufacturers like Shokz have been working on improving this, and they’ve made great strides already.
In the early days, bone conduction headphones often didn’t have enough bass. The companies fixed it to the point where some models had too much bass, and the treble and mid-range audio was drowned out.
Most of those issues have since been resolved, and the primary complaint is that they don’t offer the same depth of sound as standard headphones. Most people will not even notice the difference, but for audiophiles, that’s not the case, and bone conduction headphones won’t be their go-to option in most cases.
Conclusion
Bone conduction is an incredible technology that can let you listen to music or podcasts without blocking your ears. The way they transfer sound through vibrations in your facial bones ensures you can still hear your environment even while wearing your bone conduction headphones. The sound quality may not be quite as good as other options, but the technology is evolving rapidly.
