YK> Is there a program or a device that can filter out the musical 
instruments
 YK> from a song and leave only the human voices ?  I asked that question in
 YK> another mail net, but they didn't reply.
unless there's been some hugh technical breakthrough that i haven't heard 
about, no :)
If you think about what a song actually is - ie, all the tracks (guitar, 
bass, drums, vocals, etc) are combined down to two tracks (left & right), so 
you don't have a separate signal for everything. Now, as humans, we can hear 
the differences in sound for each insturment. But computers or any audio 
hardware can't, they just have 'sound'.
For example, lets say you have some grape juice (the guitar) and some apple 
juice (the vocals). now, once mixed together, there's really no way to 
seperate them. I suppose you could go through each molecule and say "Oh, this 
is an apple juice molecule" ... but.. ;) If you were to do that with regular 
sound, ha ;) "Oh, this blip is part of the guitar".
If there's some program that can split it up, then i'd really like to hear 
about it. Closest thing you can really do is narrow down the sound to a 
specific frequency range, but, often vocals frequency range overlaps with the 
rest of the insturments. 
Cubease VST along with WaveLab 1.6 can do some really really interesting 
stuff (went to a seminar on it the other day). It can split drum tracks apart 
-- identify the peaks (when a drum has been hit) and then splits each 
individual sound up (if theres overlapping then that'll stay) but you can 
basically get tracks for each bit of drums - kick, highhat, snare, toms, 
cymbols.. That way, if you have a recording where the cymbols came out 
sounding badly, then you can boost up their level, or even adjust the 
frequency, and expand the 'stereo image' so it sounds bigger. (Wavelab does 
that stuff).
Its not really what you're asking, but fyi, Cubase VST is basically $10,000 
worth of studio equiptment for $899.. ;)
ttyl, greg
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