I doubt the towel actually touched the capsules. The front has the rubber c=
over, and the back is deep inside a 19mm thick piece of pine.=0D
=0D
The longest bit of unshielded wiring was on the right channel (about 10" of=
it), so I scrounged some shielded cable and replaced it this evening and I=
'll try it again in the morning. I'll do some tests with and without towel,=
and with me close by and a few metres away.=0D
=0D
It might be a faulty capsule, but that doesn't explain why it didn't do it =
in the indoors test, although a frequency analysis of that recording shows =
some tiny hills at those frequencies.=0D
=0D
It's a bit disconcerting that I can't hear it, because I can't tell that it=
's happened till I get home. Even if it's all good tomorrow, I won't know i=
f that's only because the interference source (if that's what's doing it) i=
s off.=0D
=0D
Peter Shute=0D
=0D
=0D
--------------------------=0D
Sent using BlackBerry=0D
=0D
________________________________=0D
From: =0D
To: =0D
Sent: Sun Mar 11 22:40:32 2012=0D
Subject: Re: [Nature Recordists] Re: Initial SASS test shows bands of harmo=
nics=0D
=0D
=0D
=0D
The harmonics definitely show up using Izotope RX, just in the right=0D
channel. I can't really hear any difference between the channels. I=0D
don't know what is causing the harmonics but I should think it must=0D
be either a faulty capsule or a poor connection. Perhaps touching=0D
the capsules with the towel caused an earthing issue?=0D
=0D
Vicki=0D
=0D
On 11/03/2012, at 9:50 PM, doctorobotnik wrote:=0D
=0D
> It would probably help if I included the link :)=0D
>=0D
> http://i.imgur.com/so7CG.jpg=0D
>=0D
> --- In <naturerecordists%40yahoogr=
oups.com>, "doctorobotnik"=0D
> <> wrote:=0D
>>=0D
>> Hi Peter,=0D
>>=0D
>> This is how your test file looks in Audition's spectral view. I=0D
>> don't see the harmonics you noted in the right channel. Perhaps=0D
>> it's a quirk in Audacity. Do you have access to another spectrum=0D
>> renderer to try the file on?=0D
>>=0D
>> Ben=0D
>>=0D
>> --- In <naturerecordists%40yahoog=
roups.com>, Peter Shute <pshute@> wrote:=0D
>>>=0D
>>> Yesterday morning I made a 20 minute recording at the local=0D
>>> wetlands with my new SASS array (4 x EM172's in a Rob Danielson=0D
>>> style wooden structure, half finished - no nose baffle or=0D
>>> internal baffling). I also made a recording using the Sony PCM=0D
>>> M10's internal mics for comparison.=0D
>>>=0D
>>> When I loaded into Audacity and displayed the spectrogram, I see=0D
>>> lots of bands on the right channel, about 400Hz apart, to 20kHz=0D
>>> and beyond. I can't see any sign of them in the left channel, and=0D
>>> I can't believe this thing has such good separation that it could=0D
>>> be environmental. I can't hear anything odd, but with my hearing,=0D
>>> that doesn't mean much.=0D
>>>=0D
>>> I also see no sign of it in the recording using the internal mics.=0D
>>>=0D
>>> So it must be generated in the mic circuitry? I just made another=0D
>>> test recording with it on the table here beside me, and I see no=0D
>>> sign of the bands on that recording either.=0D
>>>=0D
>>> So maybe it picked up some interference with it's unshielded=0D
>>> wiring? Maybe, but would that look like this? And I was at least=0D
>>> a kilometre from the nearest powerlines. The site is an old=0D
>>> saltworks, so there may have been some pumps running a bit closer=0D
>>> than that. The lead to the M10 is only metre long, and shielded,=0D
>>> but there are a few inches of unshielded wiring in the array.=0D
>>>=0D
>>> More intriguingly, the first 20 seconds of the recording don't=0D
>>> show the bands. This includes the sounds of me wrapping the array=0D
>>> in a towel for wind protection. The last part, where I unwrap it=0D
>>> again, also doesn't show the bands. That I don't understand at=0D
>>> all. Unless perhaps my close presence somehow damped some=0D
>>> interference?=0D
>>>=0D
>>> I've uploaded one minute of it in wav format if anyone wants to=0D
>>> have a look at it: http://soundcloud.com/petershute/sass-test-=0D
>>> harmonics. The first 20 seconds is very noisy and clipped, but=0D
>>> I've had to include it to show the band free section.=0D
>>>=0D
>>> Peter Shute=0D
>>>=0D
>>=0D
>=0D
>=0D
=0D
=0D
=0D
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