Hackaday Prize Entry: Bone Conduction Headphones

Beats headphones are very popular, they’re everywhere, and they sound like trash. That’s a shame, because there’s a century of recorded music out there that sounds really good. [WΛLLTΞCH] forgot about [Dre] and started looking into a better way to listen to music. He came up with bone conduction transducers and started one of the most interesting projects for this year’s Hackaday Prize.

Instead of driving a speaker cone that vibrates the air, passes through the middle ear, and vibrates the eardrum, bone conduction amplifiers bypass the outer and middle ear completely. Not only does this produce a clearer reproduction of sound, but it’s also great for anyone with an abnormality in the ear canal, ear drum, or the tiny bones of the inner ear.

[WΛLLTΞCH]’s first prototype is using a bone conduction amplifier and a cheap Bluetooth module, stuffed into a small 3D printed case. With two 1W transducer modules, it was enough for a proof of concept. The final design is vastly more integrated, with a dedicated Bluetooth audio module. To this, [WΛLLTΞCH] is adding microphones and the ability to take calls over Bluetooth. It’s a great project, and something that could make a great product, something we’re also looking for in this year’s Hackaday Prize.

The 2015 Hackaday Prize is sponsored by:

46 thoughts on “Hackaday Prize Entry: Bone Conduction Headphones

  1. Easily the most novel entry I’ve seen iin this year’s competition. Very marketable to boot. That’s a solid combination! Looking forward to seeing this continue to evolve!

    1. Thank you so much for the support! :) This project is very dear to me, it feels twice as good as the excitement of the design process to make a difference help others with my projects too. I’m studying EE, IoT, and entrepreneurship at Stanford over the summer, so I’ll try really hard to work on it before the entry deadline, but I’m really excited about the final prototype!

      1. I suffer from profound, mostly-conductive single-sided hearing loss, and I’d love to test these if you need a tester. :)

        While I have a bone-anchored hearing aid that I use for daily things, it’s limited to speech frequencies. Something like this that would let me properly listen to music would be fantastic!

    1. Just two headphone transducers in the neck-shoulder area, tinny as all get out. If the weight of it slipped the sound burst forth like tiny phones turned up all the way.
      Then there is Blurtooth, that century of great sound is like dirty glasses, it takes the definition down generation or two.

      There is a great use of this bone stuff. Lookup [SwimP3]. It holds a gig or few and has two drivers, 1 inch plastic cones. There is an air space then thin plastic and your skin. Used on temple area. The smallest of the bass bump and cone-less full range drivers would seem to make a better driver. Pot them in silicone.
      The way I know of the SwimP3, is a friend that swims for health uses one. Make that 4 or more. The weak link is the cooked spaghetti thin and about as tensile tough wire. It has up to 7 wires with colored coating in a 2mm thick plastic jacket. I have a box full of these players with bad wires and no way to make what I would want to use for 7 conductor wire work in the tiny spaces that worm of a cable goes. And be able to make it waterproof at the entrant points as well as the jacket, no.
      Please make a sealed, inductive charged, blurtooth coupled, bluetooth ported, music player. It will just be two cups worn with a headband elastic, no wires at all. There would be a market for it and for the version coupling to a smart phone which does not work well in water even if waterproofed. Microwaves and water vs. air.

      1. We sold these in the early 80’s at a True Value hardware store. All it was was a foam body with a radio in it. The speakers were about two inches across and pointed at your collar bone area. The speakers were just normal speakers and just shot the sound into you body and kind of resonated the sound to your ears. If you were standing next to someone who had it cranked up it sounded like a crappy AM radio from a few feet away. It was not “silent” to the people around you if it was turned up loud. Very basic AM / FM tuner.

  2. Comment about beats headphones was both unnecessary and inaccurate.
    While they definitely don’t represent the best value for money, the current line of Beats headphones are actually very well reviewed.
    Anyway, this seems like a really cool project, I’ve always wondered how bone conduction sounds, and its use as a hearing aid is a sweet idea

    1. Yeah, but good luck finding an unbiased and non-sponsored review by someone who actually understands quality audio that supports beats headphones. Anyone with any experience judging sound quality would quickly label them as terrible headphones.

        1. “It’s fairly safe to say that the original Beats by Dre Solo is one of the most—if not the most—popular headphones in the world. I found its performance abysmal.”

    2. As for bone conduction, it’s easy to try. Press a bare piezo element to the back of the jawbone, just below the ears. You can tell that you’re hearing through bone conduction, rather than through air, by using a frequency just above the limit of your normal range of hearing. You WILL be able to hear it, and higher still. Maybe even frequencies you’ve never heard in your entire life, even when your ears were new. Those are indescribably odd. I was definitely aware of the stimulus, but my brain wasn’t able to categorize it. It wasn’t certain whether it was auditory or something else. And while I could clearly distinguish between two different frequencies, pitch was ambiguous; I could not recognize and place them on the chromatic scale.

      As for Beats headphones, though I’d never buy them, I wonder if they get an unfairly bad rap. Especially in regards to those four pieces of “useless” metal, which people universally claim are there only to add weight, and make the product feel like it’s of a higher quality than it is.

      I once needed to fit a piezo tweeter in a small area. To accomplish this I removed the horn. It sounded HORRIBLE. It resonated even at moderate power levels. So I glued a piece of metal to the back of it, roughly equivalent the the mass of the horn. It worked.

      I also remember seeing a device for electric guitars that claimed to extend sustain. It was nothing more than a glamorous metal plate that one screwed to the underside of the headstock. The ad claimed that by increasing the mass of the headstock, less of the vibrational energy of the strings would be lost to the headstock and neck. Just to see if it really made a significant difference, I tried temporarily clamping a chunk of metal to my headstock. It worked too.

      So while I’d prefer the mass in my headphones to come from large and powerful drivers, are those chunks of metal in Beats headphones *really* useless? I don’t think so.

  3. Will other people hear the music you are listening to with these headphones? Somehow reminds me of the neurophone which should create the same effect via ultrasonic piezo transducers. But the problem there is that other people also hear the sounds you are listening to. So there you can’t differentiate if the sound was actually conducted by bones or by air.

    1. Yeah, I was gonna post about the Neurophone but it doesn’t use bone conduction. Instead it targets the auditory nerve itself. I tested a Neurophone on some deaf friends and two of them definitely heard it.

      As a side note, I also have a virtual reality device that makes you sense movement without mechanical or visual trickery(just 3 electrodes) that oddly enough will also give you visual distortions(for lack of a better word) if you tweak the settings. The inventors didn’t seem to be interested in the discovery though.

  4. A few years ago, the “Cynaps” Bluetooth Bone-Conduction Headset was fundraised on indiegogo.
    I supported this Project and got one Headset as pledge, which does its work inside my Snowboard-Helmet.
    Current Version of Cynaps can be ordered at maxvirtual.com
    There are also cool “maker-kits” with all individual parts to integrate in own projects.

    So nothing new about this idea, but cool anyway.

    1. The ideal place for proper reception and soundstage is on the ridge at the back of your head behind and slightly above your ears. Now that I’ve found the ideal location through testing with the wired transducers shown, I can model ergonomic arms and the body of the device to match.

  5. It seems likely that the response curve for your skull is very nonlinear. How would you correct for that? It’d be very difficult to get objective measurements!

      1. DAK are still around. I get their newsletter from time to time. The lead guy(for some reason I forget his name) left a few months ago but it’s mostly the same business overall.

  6. Any work towards improving bionic ears is great but “He came up with bone conduction transducers” seems a little misleading and disrespects the work done by others that he is building on. Anyway it’s a super important area and kudos for your work.

    The following is hearsay / my two cents; the potential problem with bone conduction headphones only need to vibrate an extremely small area yet are connected to the entire skull which would distribute vibration and act as a low pass filter. Which may make them better at lower frequencies but could explain why people think music sounds bad on them.

    1. I agree, I’m by no means claiming to have invented the concept of bone conduction :) It quite hard to explain, but the actual quality of the audio is very clear and rich, it’s part of the “PHΛNTOM” effect. It has strong bass with added haptic feedback as a result of the transmission, but the highs and midrange are clear and present with little to no distortion.

  7. As someone in a music-loving family who also has otosclerosis, this is great.

    (Not to mention, from an emergency responder standpoint, the bone-conductor headphones we have right now are HORRIBLE, and I’d love a better option.)

    Good luck, I can’t wait to see the final product.

  8. Back in my Navy day 1981 I purchased a bone phone radio. It had an AM FM radio and the bone induction speakers in a set up that looked like a small inflatable vest. It did last long and I chucked it in the trash, I regretted it ever since. It was the radio that went bad not the speaker.

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