Re: Using Etymotic Research equipment for Physiology

[Jont Allen <jba@xxxxxxxxxxxxxxxx>]

Didier A Depireux wrote:
>
>         We do physiological recordings in the Auditory Cortex and IC of
> ferrets. Our sound delivery set-up consists in a conical speculum, sewed onto
> the meatus of the ear (after cutting the ear off), with a 19mm Sony earphone
> attached to it, and a small hole in the side of the speculum to insert a 1/8"
> B&K 4170 microphone.
>
>         The 1/8" B&K just died and B&K is asking 4500$ to replace it. So I
> was thinking that instead, we might get an Etymotic Research system, using
> an ER-2 sound delivery system, with an ER-7C microphone.  Both the ER-2 and
> the 7C use silicon tubing, between the loudspeaker or the microphone and
> the ear, with outer diameters of 3mm and .95 mm respectively.
>
>         I thought we could put the tubes together, make a custom earplug
> ourselves, and use the ER-2 and the 7C for sound delivery and monitoring.
> We typically only go up to 16kHz. I was wondering whether anyone uses such
> a set-up for their recordings, and if so whether they would have
> warnings/advice they could give us. Anyone who would have a useful comment
> to make would be welcome too, of course.
>
>                                                 Thanks in advance,
>
>                                                         Didier
>
> --
> Didier A Depireux                              didier@isr.umd.edu
> Neural Systems Lab                 http://www.isr.umd.edu/~didier
> Institute for Systems Research          Phone: 301-405-6557 (off)
> University of Maryland                                -6596 (lab)
> College Park MD 20742 USA                     Fax: 1-301-314-9920

Didier,

Too bad we didn't talk about this at ARO, since we did talk, and since
you had this on your mind.

The main problem with the setup you describe is the distortion and the limited
frequency resp. But if you can live with these two problem, it is a great system.

If you need specifics, let me know. I even measured the acoustic source impedance
for most of this line of transducers.

Jont
--
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