Room reverberation can render phase-sensitive signals perceptually phase-insensitive
Evidence
If the group delay introduced by a communication channel is not smooth with frequency, and has abrupt phase delay differences in adjacent frequencies, the above-mentioned rules no longer apply. One such typical response is reverberation, where, at frequencies over the critical frequency (see Section 2.4.4), the phase response behaves randomly. In practice, most of the phase-related effects are not audible at all in reverberant conditions. When a buzzy signal is filtered with such a random phase response, the buzzyness vanishes, and the firing rate spectrogram resembles the lower-right plot in Figure 11.11. If the phase delay is changed at one frequency in such a case, almost invariably, no audible changes are introduced. In other words, a phase-sensitive signal can be made phase-insensitive by adding the effect of room reverberation to it. — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 1281
Categorization
- QUESTION: Implication worth chasing: if reverberation randomizes phase and erases group-delay percepts, then phase information is largely irrelevant for speech/audio in real rooms — yet audio coding expends bits on phase? How is that reconciled?
- XREF: Relevant to perceptual audio coding design and convolutive blind source separation, where phase randomness in reverberant mixtures is a known obstacle. — connects to: Room acoustics degrade phase-change sensitivity by roughly threefold; Room resonances, not amplifier phase response, govern audible phase distortion; Phase alignment creates a ‘buzzy’ timbre perceptible without room reflections (+2 more)
- corroborated: 2 independent passages support this claim — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 1281
Broader Connections
- Room reverberation suppresses the comb-filter colouring of amplitude panning
#corroborates(0.85) — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 1890