glossary
Phase coherence is the difference between related signals reinforcing each other or fighting each other.
Phase coherence describes how consistently related signals line up over time. Coherent signals reinforce; incoherent signals can smear, hollow out, or cancel.
It matters on multi-mic drums, layered basses, stereo effects, and any source where two channels carry related information.
A phase issue may sound exciting in stereo and weak in mono. That is why correlation meters and mono checks are useful when widening or layering sounds.
Polarity flips, timing nudges, mic placement, and plugin latency can all change coherence.
Start by protecting kick, bass, vocal, and snare. If those elements lose weight in mono, fix the phase relationship before adding more EQ or compression.
Use meters to spot risk, then listen to whether the important parts stay solid in both stereo and mono.