Uneven decay rates make a room ring at and boost specific frequencies.

Evidence

As an extreme example, if a particular frequency has a much slower rate of decay compared with other frequencies, then, as the sound decays away, this frequency will ultimately dominate, and the room will “ring” at that particular frequency. The sound power for steady-state sounds will also have a strong peak at that frequency because of the effect on the reverberant field level. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 1877

Categorization

• QUESTION: Does this explain why some rooms sound ‘boomy’ on particular notes — worth chasing with the decay-rate curves?