Reversing a single harmonic’s phase makes that frequency sound much louder.

Evidence

In anechoic listening to buzzy signals, minimal changes in group delays may be audible. This has already been demonstrated with a sawtooth wave, modified by a group delay smooth with frequency, but containing local abrupt change. In the top-left and top-right cases in Figure 11.11, the amplitude spectra are otherwise equal, but the phase of one harmonic has been reversed. This corresponds to applying a group delay of only 0.32 ms at 3100 Hz and none at other frequencies, making that frequency much louder. Such frequency-dependent variations in an otherwise smooth group delay can thus have a large effect during anechoic or headphone listening. — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 1282

Categorization

Category: Causal Relationships

• QUESTION: Why does a 0.32 ms group delay on one harmonic (3100 Hz) change perceived loudness? The mechanism tying phase to loudness perception is worth investigating.

Related

• Reversing the phase of a single harmonic can drastically change its perceived loudness (similarity 0.96)
• The power spectrum is blind to the relative phase of a sound’s components (similarity 0.91)
• Hearing perceives synchronized neural firing across critical bands as buzzy timbre (similarity 0.82)
• Headphone group delay alters audibility of phase-spectrum effects (similarity 0.82)
• Group delay of modulation is the phase representation most relevant to hearing (similarity 0.81)
• Room reverberation erases the audibility of phase changes in signals. (similarity 0.81)
• Aligned harmonic phases make sounds sharper and buzzy (similarity 0.81)
• Room acoustics degrade phase-change sensitivity by roughly threefold (similarity 0.81)
• Delays under 100 ms are heard as timbre change rather than distinct echo (similarity 0.80)
• Phase differences affect loudness only at low modulation frequencies the ear can track (similarity 0.80)
• Short sounds decay in perceived loudness faster than long sounds. (similarity 0.80)
• Spectrum magnitude, not phase, drives the perceived timbre of a sound (similarity 0.79)
• Louder signals need disproportionately more dB to double perceived loudness (similarity 0.79)
• Synchronized phase harmonics produce a ‘buzzy’ sharpness perceptible without room reflections (similarity 0.79)
• Echo time delay determines which frequency components get filtered out (similarity 0.79)