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.
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.