Interaural level differences of 1-2 dB produce just-audible lateral displacement

Evidence

A similar dependence of perceived lateral displacement can be obtained if, instead of level differences, differences in the phase of the signals presented to the earphones are used. If, at frequencies below 1500 Hz, the left earphone delivers sound impulses about Ims later than the right earphone, the image shows a lateral displacement totally to the right (R5). If the left earphone leads by 1 ms, the lateral displacement is completely to the left (L5). Between these extreme positions there is a smooth transition. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1714

Lateralization is governed by differences in level and time of the sounds presented to the two ears via headphones. Figure 15.12 shows the dependence of lateralization on inter aural level differences. Pure tones of 1 kHz were used for the experiment. The levels of the tones presented to each ear were chosen such that their overall intensity corresponded to a sound pressure level of 80 dB. Positive values of the interaurallevel difference indicate that the earphone on the right ear of the subject was fed by a higher voltage. … As can be seen in Fig. 15.12, a centre image with no lateral displacement shows up for zero interaural level difference; this judgement is seen to have very little variability. With increasing interaurallevel difference, the sound image shifts more and more to the right. For negative values of the interaurallevel difference, the sound image shifts more and more to the left. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1709

Categorization

• corroborated: 4 independent passages support this claim — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1714; Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 1709
• XREF: connects to: A 5-dB hearing asymmetry doubles the perceived interaural level difference — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 1582; Contralateral efferent inhibition amplifies interaural level differences; Ceiling reflections are as detectable as lateral ones despite weak binaural cues — Toole, Floyd E, Sound reproduction- the acoustics and…, 625 (+4 more)

Broader Connections

• A 5-dB hearing asymmetry doubles the perceived interaural level difference #expands (0.80) — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 1582
• Contralateral efferent inhibition amplifies interaural level differences #expands (0.75)