Phase shift and polarity are two different things. A phase shift of 180° is "polarity reversal."
But if a device phase shifts 100 Hz by 27°, 400 Hz by 121°, and 1000 Hz by 90°, you can't "fix" that with phase reversal.
- John
Ah, I haven't known that...
But doesn't it apply to any parallel processing? I am thinking simple parallel FX loop...