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Re: Initial SASS test shows bands of harmonics

Subject: Re: Initial SASS test shows bands of harmonics
From: "Luis do Carmo" lecarmo
Date: Sun Mar 11, 2012 12:40 pm ((PDT))
The M10 has a speaker and so a magnet in its body. Even if the speaker is n=
ot in use, the magnet produces a magnetic field of its own.


Luis



From: Peter Shute <>
To: "" <>
Sent: Sunday, March 11, 2012 4:09 PM
Subject: RE: [Nature Recordists] Re: Initial SASS test shows bands of harmo=
nics

The clipped noise is from me handling the array as I wrap the towel over it=
.

I've just proven it's interference from the M10. With the recorder on top o=
f the array , the effect is reproduced. With the recorder upside down it's =
even stronger. With the recorder inside the array, pressed again the wiring=
 between left and right under the top, it's very strong, and I can clearly =
hear the hum from it.

Interestingly, with it insdie, pressed against the cable but upside down, t=
he effect is nowhere near as strong. Thus, the interference is coming from
 underneath the M10.

Even 1m away, I can see the regular spikes on a frequency analysis, but it'=
s too weak to see on the spectrogram.

Just to be sure it's electrical interference, not acoustic, I held it in fr=
ont of the mics, 1cm away, and the effect is weak. Therefore it's electrica=
l interference from underneath the M10.

The effect is on both channels, but is far stronger in the right channel, I=
 assume because I ran the wireing from the right over to the left before jo=
ining to the cable I plug into the recorder, and so there are a few more in=
ches of wiring on that channel.

But perhaps Raimund is right, that it's caused by the PIP struggling with 4=
 capsules. Can anyone recommend a battery circuit I could try? I was going =
to look into this anyway. Is it safe to just put a voltmeter across a capsu=
le to check it?

Now to get out of this house, and try some more tests at sunrise.

Peter
 Shute

From:   O=
n Behalf Of Raimund 
Sent: Monday, 12 March 2012 4:46 AM
To: 
Subject: [Nature Recordists] Re: Initial SASS test shows bands of harmonics



Because the noise obviously starts on the first occurence of the broad-band=
 and clipped noise (which does not seem to be an acoustic signal), I would =
guess that it might have something to do with PIP power
 provided by the recorder. It could be that the PIP supply circuitry just d=
oes not work properly due to the heavy load by the four capsules. So, you m=
ight try to power the capsules by an external battery.

Raimund

--- In <naturerecordists%40yahoogrou=
ps.com>, Peter Shute <> wrote:
>
> The link to the sonogram image works now. The album wasn't set for public=
 viewing, I assumed that setting was the default. Sorry about that.
>
> https://picasaweb.google.com/pshute2/March112012#5718478097647090786





------------------------------------

"While a picture is worth a thousand words, a
sound is worth a thousand pictures." R. Murray
 Schafer via Bernie Krause.

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