I tried doing what you said, but I do not think it has worked.
I am trying to isolate the synth from the second 8 bars of Cabinet Man (linked below) (drums already excluded due to being in a seperate track already).
I got the .flac stem from a dropbox linked by the artist, that had the synth and guitar.
I split the first 16 bars into 8 with the guitar, and 8 with the guitar and synth.
However, when I bounced the phase inverted track 1 (in the image below, with track two muted,) I believe that due to track one being phase inverted, it should have acted as a negative waveform to the original guitar sample and therefore cancelled it out, making me able to isolate the synth. Instead, it acted (as far as i can tell,) as a duplicate track to the guitar, irregardless of whether the original was phase inverted or not.
The only thing phase inverting did, was if track 1 was inverted and the other not, (or vice versa), it would sound the same as if there was only one track playing the guitar. If both were inverted, it sounded the same as if neither were inverted, (which makes sense, i guess.)
My question now is why does it sound like there are one or two tracks playing guitar, instead of zero or one? (excluding the track with the synth and guitar, which made no difference to the rest of it)