Subject: Re: HC selectivity ... was Re: Physiological models of cochlea activity - alternatives to the travelling wave From: Reggie Weece <weece@xxxxxxxx> Date: Sat, 29 Sep 2007 11:23:03 -0500 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>Bob and Matt - The difference between your two values for the cut off frequency appears to be the 2pi factor. From http://en.wikipedia.org/wiki/RC_circuit, wc = 1/(RC) rad/s fc = 1/(2piRC) Hz Thus wc = 25000 rad/s (not 25 kHz, as Matt suggested!) Bob's calculation of fc = ~4kHz is correct. - Reggie > Date: Fri, 28 Sep 2007 08:24:35 -0400 > From: Bob Masta <audio@xxxxxxxx> > Subject: Re: HC selectivity ... was Re: Physiological models of cochlea activity - alternatives to the travelling wave > > On 28 Sep 2007 at 12:55, Matt Flax wrote: > > <snip> > > > With respect to a hair cell at rest ... take the following general > > values for membrane resistance and capacitance : > > R= 40 Meg Ohms ... taken from [4] for example > > C= 1 pF ... taken from [5] for example > > The first order cut-off frequency would be about 25 kHz. > > fc=25 kHz. > > How do you obtain this 25 kHz value? Using > f = 1 / (2 * pi * R * C) > I come up with about 4 kHz. > > Best regards, > > > > Bob Masta