FabFilter User Forum
FabFilter Pro-Q 4 PHASE Issue
I believe I just replied to your email as well. Spectral mode is a linear phase issue. Any spectral processing, even on just the side signal, should not cause any phase issues. Can you describe your experience a bit more detailed?
Ralph (FabFilter) — Dec 24, 2025
I believe there is an audible phase problem when a spectral band is applied ONLY to the "sides", but the EQ is in “natural phase” mode.