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Re: Initial SASS test shows bands of harmonics

Subject: Re: Initial SASS test shows bands of harmonics
From: "vickipowys" vpowys
Date: Sun Mar 11, 2012 4:43 am ((PDT))
The harmonics definitely show up using Izotope RX, just in the right
channel.  I can't really hear any difference between the channels.  I
don't know what is causing the harmonics but I should think it must
be either a faulty capsule or a poor connection.  Perhaps touching
the capsules with the towel caused an earthing issue?

Vicki




On 11/03/2012, at 9:50 PM, doctorobotnik wrote:

> It would probably help if I included the link :)
>
> http://i.imgur.com/so7CG.jpg
>
> --- In  "doctorobotnik"
> <> wrote:
>>
>> Hi Peter,
>>
>> This is how your test file looks in Audition's spectral view. I
>> don't see the harmonics you noted in the right channel. Perhaps
>> it's a quirk in Audacity. Do you have access to another spectrum
>> renderer to try the file on?
>>
>> Ben
>>
>> --- In  Peter Shute <pshute@> wrote:
>>>
>>> Yesterday morning I made a 20 minute recording at the local
>>> wetlands with my new SASS array (4 x EM172's in a Rob Danielson
>>> style wooden structure, half finished - no nose baffle or
>>> internal baffling). I also made a recording using the Sony PCM
>>> M10's internal mics for comparison.
>>>
>>> When I loaded into Audacity and displayed the spectrogram, I see
>>> lots of bands on the right  channel, about 400Hz apart, to 20kHz
>>> and beyond. I can't see any sign of them in the left channel, and
>>> I can't believe this thing has such good separation that it could
>>> be environmental. I can't hear anything odd, but with my hearing,
>>> that doesn't mean much.
>>>
>>> I also see no sign of it in the recording using the internal mics.
>>>
>>> So it must be generated in the mic circuitry? I just made another
>>> test recording with it on the table here beside me, and I see no
>>> sign of the bands on that recording either.
>>>
>>> So maybe it picked up some interference with it's unshielded
>>> wiring? Maybe, but would that look like this? And I was at least
>>> a kilometre from the nearest powerlines. The site is an old
>>> saltworks, so there may have been some pumps running a bit closer
>>> than that. The lead to the M10 is only  metre long, and shielded,
>>> but there are a few inches of unshielded wiring in the array.
>>>
>>> More intriguingly, the first 20 seconds of the recording don't
>>> show the bands. This includes the sounds of me wrapping the array
>>> in a towel for wind protection. The last part, where I unwrap it
>>> again, also doesn't show the bands. That I don't understand at
>>> all. Unless perhaps my close presence somehow damped some
>>> interference?
>>>
>>> I've uploaded one minute of it in wav format if anyone wants to
>>> have a look at it: http://soundcloud.com/petershute/sass-test-
>>> harmonics. The first 20 seconds is very noisy and clipped, but
>>> I've had to include it to show the band free section.
>>>
>>> Peter Shute
>>>
>>
>
>







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