To start, a ready example: six tracks as recorded, and the mix booms. Press Play, then “Mud only”: you hear the boom itself. Then pick a track below and raise “Low cut”: there will be less boom.
Mud against the middle4.0 → 4.0 dBIn the mud zone100%Tracks in the zone5 → 5
The filled area is the selected track, the thin lines are the rest. The more of them in the 150–500 Hz band, the muddier.