Detectability of tonal signals with changing interaural phase differences in noise

Area of Science:

• Auditory Neuroscience
• Psychoacoustics
• Signal Processing

Background:

• Binaural hearing allows for sound localization and detection in noise.
• Interaural phase differences (IAPD) are crucial cues for binaural hearing.
• Understanding how temporal variations in IAPD affect signal detectability is important for auditory models.

Purpose of the Study:

• To investigate the detectability of tonal signals with fixed and time-varying interaural phase differences (IAPD) in noise.
• To determine if time-varying IAPD, simulating auditory target motion, improves signal detection.
• To examine listener weighting of different temporal portions of the signal during detection.

Main Methods:

• An adaptive, two-interval forced-choice experiment was used.
• Tonal signals (400 and 800 Hz) were presented with a low-pass noise masker (3150 Hz).
• Masker conditions included diotic, diotic uncorrelated, and diotic phase-reversed; signal durations were 100 and 1000 ms.

Main Results:

• Time-varying IAPD did not improve signal detectability compared to fixed IAPD conditions.
• Listeners placed more weight on the central portion of the signal than on its onset or offset.
• Signal detectability decreased as the antiphasic moment shifted towards the signal onset.

Conclusions:

• Temporal variations in IAPD do not enhance binaural signal detection.
• Listener weighting favors the central signal portion, possibly due to binaural system processing time and onset/offset attenuation.
• Binaural processing may involve a temporal integration window, influencing how signals are perceived.