I put my White Zombie CD in today and it sounded good for the first half of track 6....then it sounded like it faded. At first I thought it was the brand new Pioneer CD/DVD player...but no other CDs do it

 

This usenet thread poses teh same question from someone who had a similar problem as you did.

As the thread mentions, CD's don't actually wear out like tapes, they just start rotting
CD's are read by lasers so there's not actual physical contact with anything except for the disc spinner. But they're made of thin plastic which will start rotting after ~10 years.
There need not be visible damage to the disk for it to show signs of aging.

 

Huh...thats pretty wierd! Good find einsatz!

 

Faded? umm no...

If your CD starts missing data you will hear some nasty noise. It cannot really "fade" the sound. However it can start 'clipping' tick tick tick. Digital distortion sounds nasty, kinda like pink noise but a lot worse. You would hear a nasty static type sound if it lost data from the ROM. Lost enough where the DAC cannot *guess* what the waveform should look like...


Oh ya, try leaving a CDR sitting with the data portion to the sun in a 90 degress+ day. Say buh-bye if the sun is strong enough...

Shelf life on CD(s) is actually pretty good in perfect circumstances.

 

When I sat faded....I mean the sound quality was there...then the treble went way down and the bass way up.....then It went back to normal....then did it again!

 

Take that digital data, copy it to a brand new CD media. Good as new.

 

haha...I wonder if that happened to any of my CD's

BTW Nicky, which Zombie CD? Astrocreep or La Sexorcisto?

 

It's digital... the only way it can 'degrade' is if the reader (aka player) has difficulty reading the CD... it's all a "1" or a "0"... either is right or entirely wrong!

 

Maybe the system was clipping......or just plain running out of juice

 

 

That's bizzare.

technically the other post is right it's all 0's and 1's... BUT

The D/A converter will try and makeup for "lost" data when it can't read it by oversampling. Or by smoothing the waveform. So technically if you did just loose a few bits, or they are hard to read for the player it could muffle the sound. But it would still sound really funky, not like a drop in treble or bass...

I have a bunch of digital audio equipment, and when one of my devices goes out of sync with the word clock it's sounds like complete ass. Can't even tell it's music. Even if the SPDIF cable is dropping a few bits it still sounds horrible... (nasty static/pink noise)

Losing one bit is drastic since binary is all a function 2^X , X=total # of bits

I.E (unsigned)

max value for 8 bits is 256
max value for 7 bits is 128
max value for 6 bit is 64

CDs are 16bit, but its 8bits for left, anf 8bits for right channel. As you can see losing one or two bits can cause drastic changes in the value of the bit form.