Is there a plugin that permits me to select two tracks that then provides the time shift between them that brings them into maximum correlation?
I’ve never seen one that can do that.
It would be very difficult to write such a plug-in, as Nyquist plug-ins access the audio one track at a time.
I’m guessing that you are wanting to do some kind if “beat matching”?
Where would be the right place to ask this question?
PS: I’m trying to get two tracks from the same source to be exactly phase matched so I can subtract one from the other.
This board is the right place, but I doubt that such a plug-in exists, and I don’t expect to see anyone volunteering to make one.
So you have two “similar but different” tracks?
If the tracks are short, or you are using a short section of longer tracks, then you could hold the selection from the first track in RAM by assigning it as the value of SCRATCH (see: https://wiki.audacityteam.org/wiki/Nyquist_*SCRATCH*_Tutorial)
Assigning sounds to scratch is tricky, because Nyquist likes to null it’s pointers, but an easier approach is to create an array from the sound (for example, using SND-FETCH-ARRAY (https://www.cs.cmu.edu/~rbd/doc/nyquist/part8.html#index278)