Factors affecting the duration effect in pitch perception for unresolved complex tones.

Area of Science:

• Auditory perception
• Psychoacoustics
• Signal processing

Background:

• Fundamental frequency (F0) discrimination thresholds for complex tones with unresolved harmonics improve with increasing tone duration.
• The spectral region and phase of harmonics influence the perceived pitch and envelope of complex tones.

Purpose of the Study:

• To investigate the effect of tone duration on F0 discrimination for complex tones with varying fundamental frequencies (F0s) and spectral characteristics.
• To determine the relative importance of envelope repetition rate versus spectral region in F0 discrimination.

Main Methods:

• F0 discrimination was measured for complex tones with F0s of 62.5, 125, and 250 Hz.
• Tones were bandpass filtered into specific spectral regions (2750-3750 Hz and 5500-7500 Hz) and presented in sine (SINE) or alternating (ALT) phase.
• Tone durations varied across 20, 40, 80, and 160 ms.

Main Results:

• F0 discrimination improved with increasing tone duration, with the effect being more pronounced for lower F0s.
• Thresholds decreased significantly with duration, e.g., from ~30% to ~3% for 62.5 Hz F0 in the lower spectral region.
• A lower envelope repetition rate resulted in a larger change in performance with increasing duration. The duration effect was smaller for ALT compared to SINE phase complexes.

Conclusions:

• Envelope repetition rate, rather than spectral region, is the primary determinant of F0 discrimination thresholds for unresolved complex tones.
• Envelope characteristics significantly influence the magnitude of the duration effect in F0 discrimination.