Trial Implant Speakers 1

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The very first sound amplification systems were nothing more than a re-purposing of the horn. The horns use predates recorded history; it was used not only to produce music but also as a means of communication in both agriculture and military endeavors. Horns increase volume via two mechanisms. The first is through directivity. Loudspeakers for example create an angle of intense volume while excluding the area opposite the angle. The other mechanism is the loading of the driver. The sound source provides low velocity vibrations into the high air pressure area at the throat of the horn. The flaring shape drops the air pressure and as this occurs the vibrations increase in velocity: a significant increase in volume occurs. A good example of this is how the small vibrating needle of a phonograph has its sound increased to

audible levels through the use of a tin Edison horn.IMG_0634

 

The horn was replaced by the Electrodynamic Loudspeaker which is still in common use today. The modern speaker uses an electromagnet coil near a permanent magnet. This arrangement creates movement through induction. Rich Lee’s magnet/speaker implant uses exactly this arrangement.

A simple implanted magnet functions as a speaker when it vibrates in response to an external electromagnetic coil. This is a very cool grind which is becoming more popular. There are areas which need improvement. The main complaint is that the volume isn’t loud enough, or in the same vein that the coil needs to be too close to the ear to be of much use. People have reported different results; some are very happy with the sound quality they get. Regardless, the ability to increase the decibels is something that needs to be pursued. An issue which doesn’t seem to get discussed much is sound quality. I’ll admit that the first time Rich had me stick my finger (with an implanted M31) in my ear I was amazed at how great it sounded; however, they obviously don’t hold up to a really great set of earphones. Sound quality certainly isn’t an issue on par with the volume problem, but it warrants mention.

The most obvious means of increasing volume is to create a more powerful or more efficient induction coil. Increasing power is simply a matter of a bigger supply of power and sturdier coils. At some point though, one realizes that lugging around a car battery to power Princess Lei-esque head coils isn’t an improvement over dollar store ear buds. There are some possible ways that efficiency can be improved through the focusing of the magnetic fields but the I think that we should first consider modification of the implanted unit instead.

A larger or more powerful magnet would likely yield better results. In fact, a larger implant footprint alone would probably increase the decibels but I think there’s an even better way. While a Horn as a sound amplifier really can’t compare with modern speaker systems, they increased volume passively.

I had the idea that we might be able to increase volume by placing a magnet inside of a slightly larger glass cylinder. The magnet would vibrate within the cylinder and it’s low volocity vibrations would be converted by the cylinder into higher velocity ones.

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This initial design, I think might be providing more decibels compared to an M31. The problem I’m having of course that I don’t have an ear implant myself with which to compare. Another problem is that sound was very “Tinny.” Finally, even walking around with the tube lodged in my meatus became very irritating as the magnet clicked inside the glass with every step. This was not an improvement.

My second model incorporates three magnets. These are arranged inside a glass tube with like poles facing, resulting in a center magnet being “levetated” between opposing fields in the tubes center. This arrangement noticeably increased the volume of sound compared to either a magnet or a single magnet in a glass tube. Additionally, the sound quality is simply awesome. I’d still say that these 3 magnet tubes leave much to be desired in terms of how loud the sound can be but seriously.. the change in quality of sound is pretty impressive.IMG_0631

Ok, so the big issue – the size sucks. I mean, I’m blowtorching tubes shut here. Ideally, I need to source some 3mm outer diameter glass tubing if I intend to make anything realistically sized for implantation. Also, going down in tube size means going down in magnet size. I’m already using magnets smaller than an M31 or M36 would be. Will this decrease in amount of magnet over ride any increases from the shape changes? I don’t know, but it is worth playing with. I’d like to have some folks who already have ear magnets try these out simply by placing them in their ear canal and using a coil. If do report a significant increase in volume and sound quality then I’ll probably move forward towards further improvements.

 

Some great links related to this that y’all might want to check out:

https://www.grc.com/acoustics/an-introduction-to-horn-theory.pdf

http://www.edisontechcenter.org/speakers.html

http://www.physics.org/article-questions.asp?id=54

http://hplusmagazine.com/2013/06/24/diy-headphone-implant/

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