# Re: BM motion

```Hi,

I believe that two-tone suppression will affect both tones.
If they are similar in magnitude you will also see distortion products.

In 1990 Geisler [1] suggested that the nonlinearity was a function of
the hair cell saturation. Personally I agree with him.

The method in which this nonlinearity is applied is still a mystery
(in the published literature) ...
As an example I bring up the 'frequency specificity' mystery.
We can imagine - using travelling wave theory - that a low freq. tone
affects a high freq. tone ... but we also notice that a high frequency
tone affects a low frequency tone. How ?

Matt

[1] @ARTICLE{geisler:1990,
author = {Geisler, CD and Yates, GK and Patuzzi, RB and Johnstone,
BM},
title = {{Saturation of outer hair cell receptor currents causes
two-tone
suppression.}},
journal = {Hearing Research},
year = {1990},
volume = {44},
pages = {241--56},
number = {2-3}
}

On Tue, Nov 13, 2007 at 09:55:31PM -0500, Fred Herzfeld wrote:
> Can I get some help with BM motion.
>
> The concept of the traveling wave on the BM has been well documented. Now
> suppose I sit on the BM at a frequency CFm greater than a particular CF.
> Let the input at the stapes be F1 with a magnitude of A1. I get an output
> (deflection) at CFm say Def1. If I change the magnitude from A1 to 2*A1 I
> get an output Def2. Because of the non-linearity the ratio of the outputs
> is not linearly related to the ratio of the inputs. But suppose the second
> input is at another frequency say F2 and I adjust its input magnitude so
> that the deflection at CFm is the same as for the F1 case and in addition.
> The first case is as if I had two identical inputs at the stapes. In the
> second case I have two different frequencies at the input each of which
> gives individually the same deflection.
>
> Can I assume that the non linear effects will be the same so that as far as
> the measurements at CFm  are concerned I cannot tell the difference between
> the two cases ??
>
> My conclusion is that I cannot tell the difference!!
>
> Fred
>
>
> --
> Fred Herzfeld, MIT '54
> 78 Glynn Marsh Drive #59
> Brunswick, Ga.31525
> USA

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