Inverting tracks to rip unreleased tracks

Around a month ago someone ripped a music track with a V&E track and a VM&E track by “inverting” them. This was the result:

It sounds completely clean and people in the comment section asked TheTSD how they did that. They stated the following:
“Extracted two tracks from the fla file (BFB 26 - 16) and inverted them with audacity.”

But how? How was this possible? I know there’s a invert effect in well… Effect but I don’t think that one is made for ripping.

If any of you know how to replicate what TheTSD did to result in an unreleased track, please tell me. Anyways here’s the link to the google drive folder I made that has the two tracks from a .fla file of BFB 26:

Mixing is done by summation -

You can mix two or more tracks and then later mix-in a inverted copy of a track to subtract it out (i.e. “adding a negative” is subtraction). Under ideal conditions this works perfectly.

But usually “other things” are done (maybe just a level change) during mixing and usually if you have one unmixed track you have them all so there’s no reason to do this…

It’s a fairly easy experiment in Audacity to mix your voice with a song, then open the mixed file and subtract-out either the voice or music.

Or if you just take any recording an mix an inverted copy with itself you’ll get pure-silence.

So the goal is to isolate the music bed?

The second track seems to be voice and effects and the first track is the theatrical mix of everything. Open them both in Audacity. They should appear one over the other. Select one and Effect > Invert.

When you play, Audacity will mix the two (unless you tell it not to). It will export the work that way, too. If you get insanely lucky, the volume and timing will be perfect and the cancellation will be complete. If you’re not, one will be sooner than the other or one will be louder and kill the cancellation. Any error will mess this up.

If they don’t quite cancel, adjusting the two tracks sooner and later and louder and softer can be a career move. This is not for the easily frightened.

There’s another problem, too. MP3 and most other compressed “home” sound formats cause distortions that kill cancellation. That’s one reason you don’t hear about people doing this very often. It comes up on the forum occasionally and people go great guns for a while and it slowly dies out because it just doesn’t work very well reliably and with every show.


On this occasion the invert technique works perfectly …

On this occasion the invert technique works perfectly …

That’s one in a row. Stand by for the other posts complaining that it failed to work on their show.