Zwicker effect

Didier A. Depireux didier at bluenote.isr.umd.edu
Mon Jun 23 09:49:21 EST 2003

John H. <john at faraway.com> wrote:

> The other issue I'd like to raise here is that hearing has two primary
> processes. Most sound is heard through non-amplification in the inner ear,
> but there is a mechanism where some hairs are acutely sensitive to v. low
> levels 

I am not Tony, but... what are you talking about? 
First, hearing is always amplified. In your ear, you have 1 row of inner
hair cells, and 3 rows of outer hair cells. The role of the outer hair cells
is to amplify any incoming sound. Anything below 40 dB or so (it's frequency
dependent) will be majorly amplified by the OHCs. Objective tinnitus,
produced inside the cochlea, is due to a group of OHCs spontaneously
oscillating, thereby causing fluid movement near the inner hair cell and
causing the sensation of a sound. 

The ear is a very active system indeed, not a passive frequency
decomposition system. Unfortunately, it gets so active that it sometimes
goes awry and generates sounds. 


Didier A Depireux         ddepi001 at umaryland.edu  didier at isr.umd.edu
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Anatomy and Neurobiology                      Phone: 410-706-1272 (off)
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