If I could manage to gather up files for the music that was playing, would it theoretically be possible to cancel the music out? For example, playing a track and its inversion simultaneously should come out as silence (since the highs and lows cancel out). Would this affect my voice at all? If not, it sounds like it’s my best bet.
That can work perfectly if the conditions are perfect. Audacity does have an Invert effect and if you mix an inverted copy with the original digital file, you’ll get digital-dead silence. Or, if you happen to have a mix of sounds including a digital file and some other sounds, you can subtract-out the digitl file/sound, leaving everything else untouched. …So, you can try it!
But if the levels, timing, or phase, are not identical it will not work. Usually, something gets changed during the mix… And if you have an unaltered copy of the music/background, you usually already have an unaltered copy of the voice too, so there’s no need to do this.
Here’s are some examples of what won’t work - Record yourself saying “Hello”, and then record yourself saying “Hello” again. If you subtract one from the other, you will NOT hear the SOUND difference… You’ll hear you and your imaginary twin saying “Hello” together… Because of the random timing/phase differences, it turns-out that subtraction sounds exactly like addition (in this scenario).
Or, if you subtract the Karaoke version from the original, you won’t get vocals-only. The music is different and you’ll just get a mix of the two songs.
Or, if you subtract Billy Jean form Thriller, you won’t hear the “difference” between the songs, you’ll just hear two Micheal Jackson songs playing at the same time.
…The sound of the difference is not the same thing as the difference in the sound.
(since the highs and lows cancel out).
This has nothing to do with “highs and lows”. The individual digital samples will be subtracted one-by-one. (i.e. 44,100 samples per second.)
If you still have the music, and it’s your voice, then your “best bet” is probably to start over.