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Re: Matching electrets

Subject: Re: Matching electrets
From: "klangstrand" klangstrand
Date: Sat Apr 6, 2013 2:25 am ((PDT))
Thanks for excellent input everyone!
I think I will go for the multimeter-solution.
I am currently on the EM172=B4s and getting the 470 ohm across the pad 1 an=
d 3, with a variance of 2-3 (469-472)
So am I right that the capsules should be within 0.1 of eachother (f.ex 470=
.1 and 470.2)? If so, I need a better multimeter.
Secondly, if this is right, am I right to assume one would be lucky to get =
a matched pair out of a batch of ten capsules?
Sorry for my lack of insight BTW, I=B4m working on it:-)
Best
-Anders



--- In  "Mike Rooke" <> wrote:
>
> Measure pad 3 to pad 1 note the resistance, sort pairs that match to with=
in 0.1R or better.
> Confirm selection in a 94 dB calibrator once the leads are attached.
>
> -M
>
>
> --- In  "rock_scallop" <john_hartog@> wr=
ote:
> >
> > Hi Anders,
> > I am not sure what the best or easiest way is but this is what I did to=
 make pairs from ten em172 capsules - the capsules came with leads already =
soldered on.
> >
> > Number each capsule with a marker to keep them straight.
> > Make a test fixture - stereo cable with screw terminals to easily swap =
out capsules.
> > Record a stereo recording of each EM172 capsule beside a single referen=
ce capsule. In this case for the reference capsule I used an EM158 I had ly=
ing around.
> > Open each recording in your audio editing software (I used Adobe Auditi=
on 1.5), run a frequency analysis of a section of each, copy the data to th=
e clipboard, and paste it into a spreadsheet (I used MS Excel.) You may nee=
d to adjust the frequency analysis resolution to limit frequency divisions =
to a manageable number of data points. I do not know if "copy to clipboard"=
 is a common feature with other editing or analysis software.
> > In the spreadsheet, subtract the left (reference) channel from the righ=
t (EM172) of each set to find the differences in frequency response.
> > Plot the points to make a graph showing the differences from reference =
of all ten capsules, and use that to decide the best pairing.
> >
> > It will be interesting to hear how others have done it.
> >
> > John Hartog
> > oregonsoundscapes.com
> >
> > --- In  "kronseth" <anderslangstrand@>=
 wrote:
> > >
> > > Hi everyone!
> > > Sorry if/that this question has been raised probably infinite times..=
 So I have received a batch of electrets, both omnis and cardioids.
> > > The ones I have bought before have come in matched pairs, but this ti=
me I=B4ll have to do it myself.
> > > I understand there a quite a few ways of doing it. Anyone has a prefe=
rred method?
> > >
> > > Best
> > > -Anders
> > >
> >
>








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