Too much energy in the low mids can make a mix feel loud but unclear.
Cause
Many instruments stack in the same range
Vocals, guitars, keys, bass harmonics, room tone, and reverb often overlap in the low-mid range. Each source may sound fine alone, but together they can mask detail and reduce punch.
The buildup can also make a limiter react earlier because dense low-mid energy raises overall loudness without adding clarity.
Diagnosis
Compare solo tone to mix balance
Sweep carefully, but do not make decisions from a soloed EQ move alone. Mute groups, compare references, and watch whether the mix gets clearer when one section contributes less low-mid weight.
If vocals disappear, drums feel small, or the master gets loud before it feels open, low-mid buildup may be part of the issue.
Fix
Make space with small moves
Use high-pass filters, narrow cuts, arrangement choices, and shorter reverbs to reduce overlap. Small subtractive moves across several tracks usually sound more natural than one deep cut on the master.
Meter Core helps confirm whether cleanup improves loudness and peak behavior rather than only making the mix brighter.