Kaori's Headphones

The idea of making my own headphones all started a year ago, when my good friend Kaori decided to build his own because his current pair "weren't good enough."

That being said, he created something truely insane. Headphones with a midrange -and- a tweeter, and connected by insanity -- RG58 and BNC connectors.

We call them Kaoheissers. A spoof of Sennheisers, the makers of the world's best headphone (or what many believe is), the HD650.

Kaori's plans for his headphones (made after the fact):

Kaoheisser plans

Kaori's headphones:

The Kaoheissers

View of the cabling and connections:

The Kaoheissers' connections

Cyanoacry's Headphones

Notice: I'm also going to be at Otakon 2005 with these. If you see me, feel free to ask me to try them on -- they really sound good! I promise!

About 6-7 months later, in the midst of 2005's spring, my headphones started to break too. The old pair of hacked up Sony MDR-CD580's were just getting old. I'd already hacked them several times in order to get it to work -- including replacing the mini-stereo jack with a length of CAT5 with RCA connectors, and then finally changing it to an RJ45 connector.

The old headphones:

The old headphones

They were technically okay, but the acoustic damping foam was a little lose, and they'd either have too little bass, or just not work properly.

It was some time during the month of March 2005 that I managed to visit an electronics store -- Marvac. (The one close to me in Pasadena had recently closed, and were remodeling -- I had to go all the way to Costa Mesa to visit the store, some 20+ miles.) I picked up some cheap $5 drivers and headed home with them, intent on making something like Kaori's. They were 4" square drivers, rated at 150Hz-10KHz, 8 Ohm impendance, with a maximum power rating of 2 Watts. It was geek impulse buying.

I managed to whip up a quick prototype, which looked pretty silly. I was originally aiming for a design like the AKG-K1000, but it later occured to me that they're not very stable. I'd move my head around and they'd slide, and most of all, they looked absolutely ridiculous. Not that I couldn't live with that, but they were geeky to the point of making me laugh.

The floating driver prototype:

Floating drivers

Another view:

Floating drivers II

Side view:

Side view

After trying to get those to stay on my head, I guessed it would work just fine if I added foam around the drivers and let them hang off my head like normal headphones. The end result was comfortable, and it suprised me -- there was more bass because of the foam. The foam created a nice sealed chamber for the drivers to pump into -- which means that they were more efficient, too.

After adding foam:

Headphones with new foam

The Birth of the Gift-Amp

The headphones sounded nice and dandy, but they were a little quiet -- iPods and Walkmans had trouble driving the 8 Ohm load. I'd bought a cheap set of speakers along with the headphones, and there was an integrated amp in them. I took it out, slapped it in a gift-box with a 9-volt battery, and added a ribbon. The end result: a gift-box amplifier that could drive the headphones pretty loud before clipping (I would find out later that the limiting factor was the battery).

My portable listening setup:

Portable listening setup

Blurry image of the gift-amp insides:

Blurry picture of the gift-amp insides

Innards unpacked (in the background you can see the small RJ45->minijack converter):

The unpacked images

Blurry picture of the gift-amp exterior:

Gift-amp exterior

Cyan Gets an Idea

I brought these to school, and the reactions were excellent. (I was in middle school at the time, an 8th grader.) People were amazed that I'd built my own headphones, and wondered how they worked (despite the fact that they're so simple to see as is). I received several requests to buy them -- "Hey, Raymond, can you make me some?" or "Those are awesome dude, I want a pair!". Once I got back home, I figured I would be able to sell them... and make a profit. Boy, was I wrong. I went out to purchase parts for 5 headphones, and once I'd sold them, I only broke even. Buying parts non-wholesale is an expensive proposition, and I was selling them at $15.

People nicknamed these the cheesphones, because they look like cheese. They look ridiculous and had a plethora of problems -- the foam wasn't suited for this application, as opposed to the other type I'd used (this foam was from sponges), and the headband was way too thin and flimsy, as it was just a stainless steel band. The CAT5 also posed a problem, as it wasn't a very pliable, user-friendly cable. At the very least though, I'm glad I gave them headphones terminating in a regular minijack connector...

The cheesephones:

The cheesphones

Cyan Gets Another Idea

Well, with the cheesphones being a relative failure both technologically and financially, I figured I'd try again with wholesale parts and a better design. This time, it'd use flat CAT-5 which was more flexible and behaved like regular headphone cable. It'd also have an RJ45 plug at the headphones -- detachable cord so that you could use the headphones as earmuffs. The foam would be better, too, and there would be a headband that could support the weight of the drivers...

The parts arrived and I managed to put one together. It looked a-okay, sounded fine, and was much more comfortable due to the kind of foam I used.

I managed to sell several of the new version at $18, and made some sort of profit -- not much, but it was better than nothing.

The new headphones:

The new headphones

Another view:

Another view

It wasn't all that great, though. I found out that the people who bought them weren't listening to them -- they stayed in the bag I gave them, and they didn't listen to them. Apparently nobody was "brave" enough to wear them in public (What does that say about me)? With that bad feeling (I also sold a pair to one person who's not paid me yet), I decided to stop selling them. It wasn't worth it, if people bought them, but didn't appreciate them. It took all the fun out of making them.

Minor Upgrades

I changed out the foam pads on mine (the black foam was beginning to disintegrate), and changed out the drivers (the surrounds were deteriorating). I also added red tape on the right side to let people know which side was which (it's the defacto coloring everyone loves).

View 1:

View 1

View 2:

View 2

The Gift-Amp Upgrades

I'd noticed a couple of funky things over the months that I used the amp -- one thing being the discernable hum when placed next to the iPod's screen. My solution? Line the box with aluminium foil and hook that up to ground, creating primitive EM shielding. It's not perfect, but it certainly works. I also installed a diode in line with the power circuitry in case I ever figured out how to connect a 9v battery the wrong way 'round.

Better picture of the gift-amp innards:

Gift-amp innards

Picture of the EM shielding:

EM shielding

Slightly blurry picture of the top shielding:

Top EM shielding

The Shufflephones

I'd read this article and this article about the Shufflephones. The concept was simple, but what annoyed me was all the press he was getting -- he got /.'d and appeared on Hack-a-Day -twice-. Not once, but -twice-. I knew I could do better, and I knew I could make it look geekier (that's just my taste aesthetic). Those shufflephones didn't even look comfortable -- I'd tried to stuff a Shuffle in headphone cups before, and there is no way you could -not- feel them (methinks he's got small ears or something, or I've got large ones). I set out to create a shufflephone that'd be simpler, look geekier, and be a little bit more robust. The end result: Shufflephones (the new cyan edition).

First, I had to add an RJ45 jack to my headphones -- I'd been using a length of CAT5 attached directly to the drivers since the beginning. Lesson one: PCB RJ45 jacks are hard to solder when you've got to solder wires on that barely reach the connector.

Soldering job of hell:

Evil solder joints

RJ45 jack attached:

RJ45 jack attached

Another view of the jack:

Another view

That being done, I needed a very short male minijack to male RJ45 adaptor to stick the Shuffle with. I made one out of an old microphone's plug and a small length of CAT5. And with that... the Shufflephones were pretty close to completion, just needing a disguise.

The short adaptor plus Shuffle hanging:

Shuffle hanging out back

Another view:

Shuffle's not fastened yet...

I needed to add a disguise so that people wouldn't know it's a Shuffle, but I also wanted it to stand out and be conspicuous. I planned on a small toothpaste tube first (due to the fact that you can feel the controls through the tube walls), but I couldn't find one. So I used the next best thing -- a small box. Not quite as good, and rather inconvenient. It does work for when you want to look weird, though.

Shuffle in box and disguised.

With the inconvenience, I decided to just use a rubber band and strap it to the side of the driver. Very effective, it's stable, the controls are reachable, and it feels solidly built (it doesn't shake very much).

Shufflephones finished.

And with that, I'll say this: it does not take a horrible amount of effort to do something like the shufflephones (and I'm talking even with making it look nice). It's a simple hack to do.

As a side note, I'm rather impressed with the Shuffle. It can drive the headphones pretty well, despite their impendance, and it can even drive it with serious bass. For Apple to have made such a thing in such a small enclosure... is simply amazing. Hats off to you, Apple engineers. You rock my world.


People are probably wondering why I used RJ45 as the connector. Put simply, it's cheap, CAT5 (which is usually assembled with RJ45) is ridiculously overrated for audio applications, and it's a relatively common connector. With RJ45, I can plug in any length of CAT5 cable I want and use it as an extension cord, or even the main conduit. It's a rather nice thing to have.

That being said, I also use my headphones as Ethernet line testers. I have the left channel setup on RX+/-, and the right channel on TX+/- (pins 3, 6, 1, and 1). I can go up to any Ethernet jack and test for signal (it sounds like high-pitched buzzing, and hubs sound on both sides, while switches only give you RX). I really didn't want to use the other pins because often times there can be PoE on there, and I have no idea what it'd do to the drivers. Of course, I'm in real trouble if someone hooks me up with an Etherkiller...

Next up? I'm hopefully going to attach cat ears to it and hook up some sort of wireless detection system to it. Cat ears for microwave with a wi-fi detector of sorts. Scan the horizon with your head -- an interesting idea, methinks. Watch this space. ...don't laugh. It'll work, I swear!

A prototype nekomimi (catear):

Cat eared headphones

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