High-passing a reverb's input keeps low frequencies out of the tail and prevents low-end mud

Feeding full-range drums into a reverb smears their low frequencies across the reverb tail, building up muddy, boomy low end that masks the kick and bass. Engaging a low-cut (high-pass) on the reverb’s input filter removes the lows before they reach the reverb algorithm, so the tail carries only mids and highs — you get the sense of space without the low-end wash. This is why drum and vocal reverbs are almost always high-passed at the send/input stage.

Examples

In Ableton’s Reverb (Drum’s Room preset) on a drum bus: engage the Input filter’s Lo Cut and set it up into the low-mids (e.g. a few kHz for a tight drum ambience), lower the Decay, and keep Dry/Wet low so the room is felt, not heard. Compare with the Lo Cut off to hear the low-end buildup it removes.

Assessment

What happens to a drum mix’s low end if the reverb input is left full-range? Which filter on the reverb prevents this, and why is high-passing the reverb rather than the dry signal the right move?