Re: error correction

[Kim Flint <kflint@annihilist.com>]

At 8:53 PM -0700 4/13/99, Kriist@aol.com wrote:
>i was reading the flyer that goes along with the subtropics festival(south
>floridas new music festival)
>one of the composers featured performed 'prepared cds'
>he somehow(hence this inquiry)disabled the error correction function on 
>the
>cd player he would then put scotch tape with pinholes(one of the things he
>did)on the cd and play it(i guess hit the thing)
>he said that it changed the pitch, the timbre, hell, everything
>so may question to all of you tech savy guys(and gals)out there
>how hard is it to disable the error correction

I played around with this idea once. I think I even mentioned it on the
list a long time ago, since it's an interesting way to get some crazy
loops. With a little experimentation, you can get some really nutty things
to come out of a cd player. My favorite from those days was a bad heavy
metal band* cd that I painted lines on with white-out. Then I scraped some
of the white-out off so it was fairly spotty. I think it was an iterative
thing, really. I painted a bunch on, played it, didn't like it, scrape some
off, play again, etc, until I got a good result. For me, the cd player
would randomly skip around the disc, getting stuck in tight loops over bits
of audio for a while and then skipping randomly again. Sometimes it would
actually play a stretch for a little while before skipping off again.
Ofentimes I'd have to press buttons on the front to break it out of a loop
if it stuck too long. The result sounded like some wild industrial music.
Intense, percussive loops would form over little stretches of bad-metal
sound, and suddenly switch to a different bad-metal loop. Great fun.

A guy I knew then who did this weird college radio show suggested
microwaving the cds. I guess it makes lots of sparks before the plastic
around the disk shatters, leaving spider webs of lines all over the cd
surface. Probably that wreaks havoc on the poor cd laser. Never tried that
one, as I would surely starve to death if I blew up the microwave.

I don't imagine it's easy to disable error correction in the player.
Different manufacturers probably use different error correction algorithms,
so I would guess the results differ from machine to machine. However, error
correction is only meant to handle bits of dust and small scratches, so any
serious damage to the cd should completely overwhelm it. I don't know how
the guy would get pitch and timbre changes, but I'm sure you could get all
sorts of crazy stuff if you experimented with different cds and
cd-mutilation techniques.

I say, just grab some crappy cd's and go for it!  If you destroy your cd
player or any other home appliances in the process, please don't blame
me....

*Meliah Rage, remember them? no? They were much better after I finished
with them. ;-)

______________________________________________________________________
Kim Flint                   | Looper's Delight
kflint@annihilist.com       | http://www.annihilist.com/loop/loop.html
http://www.annihilist.com/  | Loopers-Delight-request@annihilist.com