About importance of "phase" in sound recognition

["Parncutt, Richard (richard.parncutt@xxxxxxxxxxx)" <richard.parncutt@xxxxxxxxxxx>]

Physiologically, we would expect sensitivity to monaural phase relations between simultaneous partials (henceforth "phase sensitivity"), since time-domain representations are present throughout the auditory system. But in an ecological-evolutionary approach we expect insensitivity to phase, since phase relationships are typically jumbled by superposition of direct and indirect sound. Thus, phase relationships carry little information that might help us identify sound sources. In sounds that begin relatively suddenly in a typical, relatively quiet environment, however, we hear the first few tens of milliseconds directly without any interference from reflections, which may be sufficient for source recognition. So evolutionary-ecological theory predicts phase sensitivity in the onset, and insensitivity after that. For similar reasons it also predicts more sensitivity to frequency than amplitude.

Richard Parncutt
Centre for Systematic Musicology, Uni Graz, Austria