Carrier interaural time shifts encode lateralization only below 1.6 kHz, envelope shifts above

Evidence

The time shifts between the signals presented to each earphone can be produced in two different ways: on one hand, time shifts can be applied to the carrier signals; on the other, interaural time shifts can be applied to the envelopes of the signals presented to the left and right earphone, respectively. In the first case, with interaural time shifts of the carrier, lateral displacements occur up to a carrier frequency of about 1.6 kHz. This frequency corresponds to a critical-band rate of 11.5 Bark. Hence, lateral displacements can be obtained by interaural time shifts of the carrier only, if the carrier shows a critical-band rate within the lower half of the critical-band-rate scale. However, interaural time shifts of the envelope lead to a perception of lateral displacements for carriers within the middle and upper range of the criticalband-rate scale. At lower frequencies, time shifts of the envelope and time shifts of the carrier are not easy to distinguish. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1715

Categorization

Category: Factual Claims

• DEFINE: Distinguishes carrier time shifts from envelope time shifts — separate mechanisms operating in different frequency ranges.

Related

• Carrier time shifts lateralize only low frequencies; envelope time shifts work at high frequencies (similarity 0.98)
• Carrier and envelope time shifts produce lateralization over complementary frequency ranges (similarity 0.88)
• Interaural level differences of 1-2 dB produce just-audible lateral displacement (similarity 0.78)