Trying to separate choral music from voice-over

[Nuclearsunburn]

Hello Audacity community, first time poster here and admittedly very novice user. I've used Audacity for over a year for mostly simple editing jobs related to different world of warcraft videos I've made, and it is such that brings me here today. I'm trying to remove the background choral music from the audio of a cinematic that's played, and just keep the voices. I have downloaded an approximate version of the music by itself (a song titled Arthas, my Son) and have edited it down so that at least to my ears, the background music lines up. I know it's not exact, and thus a direct inversion won't work, but I'm really just looking for something to even make the soprano voice in the choir quieter than the male voices speaking. Things I have tried :
Using noise removal to identify the soprano as "noise" and applying it to the track. This leaves the track with a hollow, metallic sounding "echo".
Using the knockout plug - in. This results in all my audio coming from my left speaker, or cancelling out the voice while leaving the music.
Like I said, I'm really a neophyte at this kind of thing, although I find it fascinating and most of the tech terms are alien concepts to me. If anyone can tell me what I might be missing or doing wrong I would surely appreciate it.

[steve]

About the only thing that you've not tried is "ExtraBoy" (similar to Knockout)
There is a free 14 day demo version http://www.elevayta.net/product13.htm )
If that doesn't work either then you've reached the end of the line.

[kozikowski]

The tools define "noise" differently than you do. It's not just "sound I don't want." Had the singer sung one single note and held that note exactly the same for fifteen minutes, you would be able to get rid of it with the removal tools. They're designed to extract air conditioning, fan noises and hum -- something that doesn't change through the whole show. The metrobus starting up and driving away outside your window is now a permanent performer in the show.

Identical Performance Cancellation almost never works because the two performances are never identical. We had a poster that got close with two performances from his Game Boy. It was electronic music, so it should have been a no-brainer. In that case, the audio distortion in his Game Boy (cheap) speaker amplifier killed him because it was different for each pass. Most 'with singer' and 'without singer' performances are slightly different even leaving the studio -- and any time you hit analog signals in the pathway, you're dead.

If you magnify the music enough to see the individual ups and downs in the blue waves, those are the signals that need to line up for cancellation.

This is two succeeding identical piano notes. They're similar, but they will not cancel.

Picture 3.png (12.28 KiB) Viewed 952 times

This is two electronically generated notes. These will cancel.

Picture 4.png (11.44 KiB) Viewed 952 times

It's like comparing two sugar bowls by lining up the grains of sugar.

Koz

[kozikowski]

One more point. If you have a Dolby AC3 sound track from a Movie DVD, those generally have the performers in the center and everything else in surround -- so it's already separated for you. All you have to do is rip the DVD and decode the Dolby track.

Similarly, if you have the original studio mix tapes, those have everything on their own tracks.

Koz