Can someone explain how this could happen?

I have 2 quirks I've been trying to figure out, dealing with audio cd's.
The first one, was actually a computer CDROM drive, somebody dropped it and put it back into a computer. This drive would from then on only play the vocal tracks from any audio CD. We tried many CD's that day, from Nine Inch Nails, to Stone Temple Pilots, some rap artists... and all of them played the same way. No music, only the lead vocals.
Recently, my friend's car CD player broke, and it displayed the opposite behavior. No matter what CD was played only the music/background vocals were audible, not the lead vocals.
In both cases the music was still playing in stereo, so it was not a case of simply the left or right channel being cut.

From what I've been told, there is no discrete vocal channel on the audio CD format, correct? These 2 cases seem to negate this. If the vocals were not a seperate track, how could they or the background be cut?

I have been searching for a way to duplicate this at home, for one because I'd love to extract some vocal tracks to do some remixing of songs (a hobby I enjoy), and second just because I'm curious as to how this can happen by accident, but yet noone offers any kind of hardware or software to do exactly this. Strange, since I've found it is indeed possible.
Anyone have any insight on this mystery?
I don't see how it can happen. Guess your the first.
The unit is possessed!
Get a good exorcist...
Or, you wre hypnotized and don't know it.
Although Karaoki type machines DO remove the vocal band rather well from music. That could explain at least 1/2 of your mystery.
could it beeeeee SATAN!!!!!

aloha keith
Too many drugs, or not enough!
The explanation for the rap artists is easy: there isn't any music there regardless of what you play it on. The others are harder to explain. It could be summing the left and right channels resulting in the lead vocal doubling in volume while the other elements remained about the same.

On the car CDP, it could be a 180 degree phase inversion of one channel resulting in the practically mono lead vocal track cancelling out while the more left to right panned instrumental tracks wouldn't.
I think its Satan, conjured up by too many drugs.
Swampwalker, have you been playing your vinyl BACKWARDS again, revealing the secret chants that enable one to conjure up Lucifer, himself!
!!!ouy desseug ti, torraptaF
Swampwalker, don't you mean:

"!!!ti desseug uoy, torraptaF"
!!!desufoc os m'I
Most likely there was a phase reversal of the speaker leads hooked to the monitor amp used with the computer or within the monitor amp itself, not on the audio card in the computer. To highlite vocals or instrumentals, you need to try a phase reversal game on playback. It might be as simple as reversing the plus and minus on one set of speaker leads, but better yet would be one of the old McIntosh preamps that gives you all kinds of phase-relationships: stereo reverse, right only, left only, and various combinations, either fed to one or two channels.