Estimating the perceptual weighting of interaural time difference cues in amplitude modulated binaural beats

Abstract

For an abruptly gated sound, perceived lateralization is determined primarily by binaural cues at onset. Relatively less is known about the temporal weighing of binaural cues—such as interaural time difference (ITD)—during more naturalistic modulation profiles. Here, an experiment measured the lateralization of a tonal binaural beat modulated by a diotic, 8-Hz sinusoidal amplitude modulation. Binaural beat lateralization (left/right, two alternatives) was compared to that for tones with static ITDs. Across three mean carrier frequencies (200, 500, and 800 Hz), ITDs occurring during early rising amplitude (e.g., 20–25 ms after onset) predicted the perceived lateralization of the binaural beat signals well.