Effect of sound level on pitch and timbre discrimination using low- and mid-pitched complex tones

Discrimination of pitch and spectral detail is an essential skill for audio engineers, musicians, and music professionals. Auditory tuning curves are known to expand with increasing signal strength (Evans, 1993), which in turn spreads temporary threshold shifts across cochlear bands (Regers, 2016). These observations suggest that auditory discrimination may be directly affected by the intensity of the signal. Psychophysical evidence was found in our earlier work that robust signal levels had a consistently negative influence on the accuracy of both pitch and timbre discrimination when compared to soft signals (Bulla and Chon, 2021). Discrimination performance was significantly better at 65 dBA SPL (typical conversational level) compared to performances at 55, 75, and 85 dBA SPL in a follow-up study (Bulla and Chon, 2024), suggesting a possible “discrimination sweet spot.” However, while promising, these experiments utilized sinusoidal tones for the pitch task and complex tones in the timbre task. The present study expands prior work by utilizing both tasks complex tones with low- and mid-pitches to examine the effect of pure versus complex tones at different pitches. Data collection is ongoing and results will be reported with new observations and outlines for potential future research.