Room reflections cannot be corrected by electronic 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 (#contradicts, via linked claim)

All the above uses of equalization compensate for limitations imposed by the acoustics of the recording context. To make intelligent use of it in these contexts requires some idea of the likely effects of the acoustics of the space at a particular microphone location, especially in terms of the direct to reverberant sound balance. — David Howard, Jamie Angus, coustics and Psychoacoustics, 2417 (#expands, via linked claim)

Categorization

• XREF: connects to: Broadband ETCs are untrustworthy whenever reflections differ spectrally from direct sound; EQ cannot reduce seat-to-seat variation from a room mode; Equalization only corrects sound at the measured position, not the physical resonance (+7 more)

Broader Connections

• Some professional monitors have resonance and directivity flaws no equalization can fix #corroborates (0.78)
• Room resonances are minimum-phase and yield to frequency equalization #contradicts (0.75) — , Toole, Floyd E - Sound reproduction-…, 942
• Intelligent equalization requires understanding a space’s direct-to-reverberant balance #expands (0.75) — David Howard, Jamie Angus, coustics and Psychoacoustics, 2417