Extracting things from one channel

[TPIMaster]

Hi. I've been experimenting with 5.1 audio and so far I can create a left, center and right channel, but have been unable to create the rear channels.
(I want to make "true" (I know it can never be true) channels, not just reverb the front left and right channels and call them rear)

Now, I was wondering if maybe you can extract things from one channel.

For example: Let's say you have this:

Left channel: Vocals, electric guitar
Right channel: Piano

So, what I'm saying is: is there a way to extract for example the electric guitar but keep the vocals? The vocals and electric guitar are only in the left channel, and the piano only in the right. Nothing is centered.

Thanks.

[mic]

http://www.dolby.com/resources/tech_library/index.cfm?TECHLIBITEM=8 might have some useful info.

On isolating vocals and such, the analogx site has something you might be able to use, and I know there are several other programs that include removing vocals -- it's popular for kareoke (however it's really spelled :)).

You might be able to adapt it to other instruments, or worse case, grab the vocals & subtract them from your existing track -- might get you pretty close.

[TPIMaster]

Yes I know about those programs, but what they do is remove what you can hear in both channels (for example: you have vocals in both channels, electric guitar in the left and piano in the right, then they remove the vocals, or in some cases, they do the exact opposite, keep the vocals but remove the rest) But I want to remove stuff from one channel (which is mono), not two (stereo).

[mic]

You're right about most working on stuff that's present in both rt & lft. Confess I was too tired, remembered that a few minutes later as I'd shut down and gone to bed. Sleeping on it I did dredge up some old memories though... Hope it helps. :)

The vocals usually are a rather narrow band of frequencies, and it is possible to to use filters to block those frequencies while letting others pass; it isn't easy though, because you have to worry about harmonics (where the voice or whatever appears at more then one freq range). I think sound engineers & such do it pretty regularly and one who has written about it (Jay Rose) has a site here: http://www.dplay.com/. He's written, probably still writes for dv.com -- I think you might find his articles in their archives -- & he does their audio forum.

Otherwise I think you'll find a mix of opinions... Some say it can't be done, possibly because of the hassle of harmonics, but others say they've managed using an equalizer with a lot of bands rather then band-pass or gate filters. If nothing else, an equalizer might help to narrow down the freq you have to work with, and you are lucky in the sense that guitars and voice can occupy very different parts of the freq spectrum.

And last, again hoping it helps, came across a free, VST plugin here: http://www.elevayta.com/ . Reading about it seems it might help isolating freq., & I think I read it's supposed to stick to VST standards, but don't know how well it might work in other software.
luck :)