Fletcher assumed tone audibility requires power match within a critical band

Evidence

Assuming, as Fletcher did, that a tone is audible within a noise when the acoustic power of the tone matches the acoustic power of the noise, falling into the critical frequency band where the frequency of the just-masked tone is centred, then the bandwidth in question can be estimated as follows: for frequencies below 500 Hz, masked threshold is 17 dB higher than the density level of the white noise that is masking the tone. Under the assumption of equal acoustic power at threshold for noise and tone within this band, we can calculate the bandwidth as being 1017/ 10 , i.e. about 50 times larger than 1 Hz. This would lead to a bandwidth of 50 Hz at low frequencies. — Professor Dr.-Ing. Hugo Fastl, Professor Dr.-Ing. Eberhard, Psychoacoustics- Facts and Models, 867

Categorization

Category: Factual Claims

• DEFINE: Establishes Fletcher’s power-matching assumption underlying critical band estimation.

Related

• Fletcher’s equal-power assumption implies a low-frequency critical band near 50 Hz (similarity 0.95)
• Fletcher’s equal-power masking assumption is demonstrably false (similarity 0.88)
• Equal-power masking assumption is wrong and only partly power detection holds (similarity 0.85)
• There is a critical bandwidth beyond which adding noise power no longer increases masking (similarity 0.85)
• Fletcher defined critical bands as noise regions whose power equals a just-masked tone’s (similarity 0.85)
• Fletcher originated threshold measurement, loudness relations, and masking models (similarity 0.82)
• Critical bandwidth varies a hundredfold across the audible range. (similarity 0.82)
• Noise bandwidth below the critical band does not raise masked threshold. (similarity 0.82)
• Critical bandwidth marks the perceptual shift from rough to smooth tone resolution (similarity 0.80)
• Clinical masking directly applies Fletcher’s critical band theory (similarity 0.80)
• Only tones exceeding a level-dependent masked threshold are audible in noise (similarity 0.80)
• Auditory critical bandwidth stays constant at 100 Hz below 500 Hz then rises proportionally. (similarity 0.79)
• Harvey Fletcher pioneered threshold measurement, loudness relations, and the masking model. (similarity 0.79)
• The ear’s frequency selectivity worsens as frequency rises above 500 Hz. (similarity 0.78)
• A tone and wideband noise of very different levels can equally sound loud (similarity 0.78)