Room resonances, not amplifier phase response, govern audible phase distortion

Evidence

Many investigators over many years attempted to determine whether phase shift mattered to sound quality (e.g. Hansen and Madsen, 1974a, 1974b; Lipshitz et al., 1982; Van Keulen, 1991; Greenfield and Hawksford, 1990). In every case it has been shown that, if it is audible, it is a subtle effect, most easily heard through headphones or in an anechoic chamber, using carefully chosen or contrived signals. There is quite general agreement that with music, reproduced through loudspeakers in normally reflective rooms phase shift is substantially or completely inaudible. When it has been audible as a difference, when it is switched in and out, it is not clear that listeners had a preference. — Toole, Floyd E, Sound reproduction- the acoustics and…, 972 (#corroborates, via linked claim)

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 (#corroborates, via linked claim)

Categorization

• XREF: connects to: Room acoustics degrade phase-change sensitivity by roughly threefold; Room reverberation can render phase-sensitive signals perceptually phase-insensitive — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 1281; Phase shift is largely inaudible for reproduced music in reflective rooms — Toole, Floyd E, Sound reproduction- the acoustics and…, 972 (+2 more)

Broader Connections

• Phase shift is largely inaudible for reproduced music in reflective rooms #corroborates (0.85) — Toole, Floyd E, Sound reproduction- the acoustics and…, 972
• Room reverberation can render phase-sensitive signals perceptually phase-insensitive #corroborates (0.82) — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 1281