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do bass frequencies reduce threshold for hearing of higher frequencies

Luxman Amplifiers India


New Member
Mar 15, 2009
while researching "How the human ear works" , i chanced upon this -

(excerpt) - There has been little exploration of the mechanisms by which stapedius muscle contractions reduce the masking of responses to high-frequency sounds by low-frequency sounds. To fill this gap in knowledge, controlled stapedius contractions were elicited with direct shocks in anesthetized cats, and measurements were made of the effects of these contractions on the masking of single auditory-nerve fibers and on the attenuation of middle-ear transmission. The results show that the stapedius-induced reductions of masking can be much larger than the attenuations of low-frequency sound. With a 300-Hz band of masking noise centered at 500 Hz, and signal tones at 6 or 8 kHz, unmasking effects over 40 dB were observed for sounds 100 dB SPL or less. The data suggest that much larger unmasking might occur. The observed unmasking can be explained completely by a linear stapedius-induced attenuation of sound transmission through the middle ear and a nonlinear growth rate of masking for auditory-nerve fibers. No central effects are required. It is argued that the reduction of the upward spread of masking is probably one of the most important functions of the stapedius muscle. (end of excerpt)

in essence, i think it means that the lower bass frequencies, when incident on the hearing mechanism, "tune" the ear so the ear is more responsive to the higher frequencies, and can appreciate the higher frequencies better (the perceived SPL of the higher frequencies gets a relative boost).

This means that if a music system is not able to reproduce adequate bass frequencies, appreciation of the higher frequencies will require higher SPL levels.

therefore, if a system can produce good quality bass, then music can be enjoyed at lower SPL. Of course, higher order harmonic distortions of the putative bass frequencies would negate the perceived advantage.

what has been the experience of forum members regarding this?

and again, maybe raising the floor noise in a music track using low frequencies has it's advantages?
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