Room resonances are minimum-phase and yield to frequency equalization

Evidence

Here we introduce electronic manipulation of a physical acoustical phenomenon. It is possible because low-frequency room resonances behave as minimum-phase systems, and therefore respond to corrective equalization of the frequency response peak by attenuating the time-domain ringing. To be clear, this does not eliminate the resonance when there is no equalized audio signal present. Pause the playback, have an interlude of live acoustical music and the room resonances will have their effects. However, press the “play” button and music reproduced through loudspeakers supplied with the appropriately equalized signal will be heard with the problematic room resonance(s) attenuated. This works best for one listener, where the mike is located, or possibly for a few in a row or column of listeners oriented with respect to simple axial modes. — , Toole, Floyd E - Sound reproduction-…, 942

Categorization

• DEFINE: Explains the minimum-phase property and why it licenses corrective EQ of resonances that passive traps address structurally.
• XREF: connects to: Minimum-phase loudspeaker resonances are correctable with parametric equalization. — Toole, Floyd E, Sound reproduction- the acoustics and…, 510; Frequency-response peaks prove time-domain ringing in minimum-phase devices; Modal decay times below 80 Hz are achievable with parametric equalization (+3 more)

Broader Connections

• Intelligent equalization requires understanding a space’s direct-to-reverberant balance #expands (0.78) — David Howard, Jamie Angus, coustics and Psychoacoustics, 2417