What causes mud
Mud is low-mid energy (roughly 150–400 Hz) that accumulates when multiple instruments share the same frequency range without EQ carving. The result: a thick, undefined low end where bass and kick lose separation, and the mix sounds "boxed in".
How PRISM detects it
PRISM measures the energy ratio between the low-mid band (150–320 Hz) and the mid band (320–800 Hz). When low-mids exceed mids by more than a threshold calibrated to your BPM profile, it flags a mud issue with the exact dB excess.
The fix
On each element in the 150–400 Hz range: use a high-pass filter to remove everything below the instrument's fundamental. Then use a narrow bell cut (−3 to −5 dB, Q 1.0–1.5) at the problem frequency — usually around 200–300 Hz on bass, 250–350 Hz on rhythm guitars, 180–280 Hz on kick.
Don't cut everything — you'll lose warmth. Target the buildup, keep the body.
To fix this frequency problem, here are the tools PRISM producers reach for most — each picked for this specific case, not a generic list.