Aural harmonics: estimation consistency from tone-on-tone masking measurements

Area of Science:

• Auditory perception
• Psychoacoustics
• Signal processing

Background:

• Inaudible auditory signal amplitudes are inferred using tone-on-tone masking.
• Methodological challenges include determining the optimal number and selection of measurements.

Purpose of the Study:

• To investigate the impact of sample size and masker:maskee phase angle on the estimation of subjective signal amplitudes.
• To determine reliable sampling strategies for inferring the second aural harmonic.

Main Methods:

• Tone-on-tone masking thresholds were measured using a 250-Hz masker and a 500-Hz maskee at various phase angles.
• Measurements were analyzed in subsamples of varying sizes (n=4 to 13).
• Estimates of the second aural harmonic were repeatedly calculated and averaged.

Main Results:

• For sample sizes (n) greater than 4, estimates of the second aural harmonic averaged within +/- 1 dB.
• Individual estimates showed considerable variation, especially with smaller sample sizes (up to 13 dB for n=4).
• Averaging over seven subjects with incrementing phase angles yielded estimates within 2 dB, despite individual variations up to 6 dB.

Conclusions:

• Sample sizes of six or more measurements provide reliable estimates of aural harmonic amplitudes.
• The choice of masker:maskee phase angles has minimal impact on amplitude estimation when using sufficient sample sizes (n>=6).
• This study clarifies sampling requirements for accurate psychoacoustic measurements.