Re: Using Etymotic Research equipment for Physiology (Jont Allen )

Subject: Re: Using Etymotic Research equipment for Physiology
From:    Jont Allen  <jba(at)RESEARCH.ATT.COM>
Date:    Tue, 23 Feb 1999 19:43:18 +0000

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(at) > Neural Systems Lab > 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 -- Jont B. Allen (Technology Leader), AT&T Labs-Research, Shannon Laboratory 180 Park Ave., Room E161, Florham Park NJ 07932-0971 973/360-8545voice, x7111fax, -My favorite URL: -Progress (n.): The process through which Usenet has evolved from smart people in front of dumb terminals to dumb people in front of smart terminals. -- obs(at) (obscurity)

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Electrical Engineering Dept., Columbia University