Afrotech's Hard-disk Sound System

Why pay 500$ for Klipsch's latest speaker system? You can make something that looks way cooler for the price of a DIY amplifier and some HDDs out of a dumpster. It doesn't sound quite as good but who cares! There really isn't much to say about this project... It's fun as hell to watch, easy to do, and impressed the crap out of everyone I've showed it to. Just download the movies already. But first here are some pictures:

The system, with woofer, midrange, and tweeter harddisks, lying on my favourite stolen cafeteria tray:

The amplifer I made (and the transformer powering it):

The overall system:

 

Movies that you MUST see to appreciate the project


You will need the divx codec to play the non-metacafe videos.

Porn music - Cheesy song, but good sound and shows great movement of all the heads. You can hear me trying to stifle a laugh when the heads move to the dude going 'oh yeah!'
Star wars - Because I know that all the geeks will want to see this. Good movement of all the heads. See the platter of the tweeter spinning?
Spybreak (The Matrix theme)
Nothing special to watch but I like that movie damnit
Porn music 2
Slow and funky, its cool to watch the heads jerk about to the bassline.
Porn music 3
Fast and groovy, the sound quality from the drives is excellent. Have you guessed that I like porn a lot yet?
Synaesthesia 1
 Not much movement that you can see, but good sound and its probably my favourite trance song ever. Halfway through the video I flip the camera around so you can hear the sound a little better with the microphone closer to the drive.
Synaesthesia 2
 The drives look a little more active when the chick is singing. Btw, that scrap of paper I keep focusing on says Afrotechmods.com but due to the high video compression you can't see jack because I am an idiot.
Yatta 1
 If you don't know this song by now, you don't browse the internet enough. Q Q Q Q US US US US.... I!
Yatta 2
 My! I have never seen hard drives vibrate with such irrational exuberance before!

Every sound you hear in these movies is being produced by the harddisks and nothing else. The sound quality is in fact much better than what you'll hear in these movies because the microphone of a digital camera isnt exactly the best thing ever...

Im sure you are confused as hell by now. Here's how it works:

First I got 3 dead harddisks. A small one that used to be my Amiga's, a normal sized one, and a bigass ancient one. I did this just for the fun of saying I have a harddisk sound system with woofer, midrange, and tweeter drivers ;). I ripped the drives apart. I took sound (in electrical signal form) from the output jack of my sound card. I fed it through a Velleman 30 watt audio amplifier that I bought from Parts Express here and soldered together. I took the amplified signals and fed them through the coil that controls the movement of the HD drive heads. I also connected the amplified signals to the platter motors of the 'midrange' and 'tweeter' drives, so you can actually see the platters spin sometimes. I determined which places to connect the wires by studying the drives and poking wires around in random places. Hey... they were dead anyway. Anyways, the sound that is being produced is from the rapid vibrations of the heads/platters due to the 'sound' signals passing through them. With lower frequency sounds being passed through the drives, you can see the heads move quite a lot. For the high frequency ones, its invisible to our inferior human eyes. This kind of fun isn't just limited to harddisks... I also got low frequency sounds to come out of an electric motor, and even standard cooling fans will make some sound. Girls can try even making music come out of their vibr... *cough*... The 3 harddisks are connected to the amp in parallel. It's like ghetto raid with groove ;)

To build your own: First find 1 or more dead harddisks. Rip them apart so everything is showing. Look in the area near the drive heads. There should be 2 little wires that lead into the induction coil that controls the movement of the heads. The exact location of this will be different for every drive. Either attach extension wires directly to those 2 little wires, or follow the circuit trace and look for a more convenient place to make the connections. Jam amplified sound through the coil, and you will get the sound you seek. The amplified signals can come from any amp - your home stereo, car stereo, or one you make yourself like I did. From my experience, when the signals are around 3V to 8V RMS out of the amplifier, you will get the best sound so adjust the volume accordingly. If you want to get sound out of the platters themselves, look for wires or traces etc. that lead to the area where the motor that rotates the platters is. Connect the sound up to them. Poke around - some points give louder sound than others! Wire all the little 'instuments' in parallel to the amplifiers outputs.

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