Using samples to phase invert?

[quote quote="kiakenra":2ygkymtl]ok just wanted to explain this to ppl and hear wot ppl think, say you got a track with an acapella in it you want, phase invertion didnt works with your instrament and nither did whacking a formant filter on it.

check this out

most songs (mainly mainstream) follow a construtive pattern were a different sound is brought in after X bars, and most of the time there with be all the sounds thats are in the song minus the lyrics. with the correct use of sampling and pitch correction, the entire song can be constructed, and then simpley phase inverted!

let me know wot u think

[/quote:2ygkymtl]
Not really feasible, due to uplifters/downlifters and similar FX which will completely distort every group of bars. Mastering will also distort things (depending on how heavily compressed it’s been) so they won’t phase invert perfectly. There are a lot of things which will cause it not to phase invert very well (if at all).

You can sample individual beats or groups of beats that are clean and have no FX going on over the top and try to phase invert as best as possible on other bits of the track, then use a center extraction tool or noise reduction to try and get rid of other things. It would take a long time, though, and probably not worth the effort because the acapella still wouldn’t be very clean in the end. It’s easy to phase invert bass even if it doesn’t match up perfectly, but the high end stuff like uplifters/downlifters/crashes/synths will always come through at least a bit unless you have a perfect and identical copy of it to invert.

Some old tracks have been phase inverted from other bits of track to pull out quite a clean acapella. I remember years ago when I was studying at school we had an old vinyl track that somebody had managed to phase invert the vocals out of from other parts of the track, and that was back in the days where they really didn’t play exactly to time, so it would have been extremely difficult to do that. But some expert sound engineers do have the ability to sit there for hours and hours and get some decent results from phase inversion. It’s a very long-winded task, though, not one I’d recommend wasting your time on!