Towards a measure of auditory-filter phase response

Area of Science:

• Auditory Neuroscience
• Psychoacoustics
• Signal Processing

Background:

• Auditory filters are crucial for processing complex sounds.
• Understanding their phase response is key to explaining auditory perception.
• Previous research has explored filter properties, but phase curvature remains less understood.

Purpose of the Study:

• To investigate the relationship between auditory filter phase curvature, center frequency (CF), and sound level.
• To estimate the phase curvature of human auditory filters.
• To compare findings with peripheral physiological data and existing models.

Main Methods:

• Utilized harmonic tone complex maskers with adjustable component phases.
• Systematically varied masker phase curvature and measured sinusoidal signal detection thresholds across a wide frequency range (125-8000 Hz).
• Investigated the influence of masker level on phase effects at specific frequencies (250, 1000, 4000 Hz).

Main Results:

• Significant differences in detection thresholds (≥20 dB) were observed based on masker phase curvature.
• Estimated auditory filter phase curvature decreases sharply below 1000 Hz CF and changes slowly or remains constant above 1000 Hz.
• Phase curvature appears largely independent of overall masker level.
• Results align with peripheral physiological findings but differ regarding phase curvature sign reversal at low frequencies.

Conclusions:

• The study provides a method for mapping auditory filter phase curvature.
• Findings offer constraints for developing models of peripheral auditory filtering in humans.
• The observed phase responses are likely of peripheral origin, contributing to our understanding of auditory processing.