If the question is can we make Vocal Removal perfect? Not so far. Most modern songs include stereo vocal effects and other left-right spacial modifications that escape Center Pan Removal because they’re not in the center.
http://kozco.com/tech/audacity/clips/MysteryTrain3.mp3
Before and after.
The standard Vocal Removal is a packaged version of that thing on YouTube where they show you how to split stereo, invert one channel, etc, etc. The new removal tool does all that, but has extra filters so all the bass and drums may not go, too, but that’s about it.
As you suggest, this isn’t rocket surgery. Cancellation is a simple math problem. Anything further than that can be very entertaining.
https://forum.audacityteam.org/t/removing-a-voice/33051/1
There was a posting where Robert J. H. added some more functionality, but I can’t find that posting.
Vocal Removal makes it seem you can do so much better with just a little effort and that’s not true. Past the simple math, you run into the universal truth that we can’t split a mixed recording into individual instruments, singers and sounds. That truth is the killer of many sound shows. See #4.
The Four Horsemen of Audio Recording (reliable, time-tested ways to kill your show)
– 1. Echoes and room reverberation (Don’t record the show in your mum’s kitchen.)
– 2. Overload and Clipping (Sound that’s recorded too loud is permanently trashed.)
– 3. Compression Damage (Never do production in MP3.)
– 4. Background Sound (Don’t leave the TV on in the next room.)