Human loudness-modulation detection is fastest around 4 Hz

Evidence

The detection threshold of amplitude modulation indicates some properties of human ability to perceive changes in loudness. As will be shown below, the greatest sensitivity is obtained when the modulation frequency is about 4 Hz. The detection threshold of the level of modulation of a 1-kHz tone and white noise is shown in Figure 10.13 as a function of the level of the signal. When the level of the carrier signal is increased from silence, the threshold decreases monotonically. With relatively low levels (20–50 dB) the detection threshold is about 1 dB, and at higher levels the threshold keeps decreasing, reaching about 0.2 dB at 100 dB. Interestingly, when the same test is conducted with white noise, the detection threshold is constant at all levels above 25 dB. — Ville Pulkki, Matti Karjalainen, Communication Acoustics- An…, 1163

Categorization

Category: Factual Claims

• DEFINE: JND of level quantified: about 1 dB at 20-50 dB, shrinking to 0.2 dB at 100 dB; a key hearing sensitivity baseline.

Related

• Amplitude-modulation detection improves with tone level but is level-independent for noise. (similarity 0.93)
• Humans detect level changes of about 1 dB at moderate volumes (similarity 0.85)
• Human hearing is most sensitive to sounds around 3-4 kHz. (similarity 0.83)
• Humans are perceptually tuned to amplitude and frequency modulations across specific rate bands (similarity 0.82)
• The ear is most sensitive to amplitude modulation near 4 Hz (similarity 0.82)
• AM tones change perceived frequency spread, giving extra detection cues that noise lacks. (similarity 0.81)
• At very high modulation rates, listeners detect AM only via average intensity change. (similarity 0.81)
• Just-noticeable amplitude modulation drops steeply as tone level rises (similarity 0.81)
• Temporal modulation detection is independent of hearing threshold (similarity 0.81)
• Level discrimination thresholds grow steeply near hearing threshold (similarity 0.81)
• Rapid AM of noise is heard via overall level, not its rapid fluctuations (similarity 0.81)
• Frequency discrimination thresholds rise dramatically from 500 Hz to 5000 Hz (similarity 0.80)
• The auditory system represents modulations below 55 Hz well and worse above (similarity 0.80)
• The loudness function approaches a vertical asymptote at the 3 dB threshold in quiet (similarity 0.80)
• Modulation power is captured by filters tuned to 2, 4, 8, and 16 Hz (similarity 0.80)