[microsound] Zoom H4 tech query -- anybody else?

[Mike]

Hi
      The H2 is similar when used as a usb audio device. Perhaps try a  
different memory card. The periodic noise could be related to the H4s  
write/card interface. A phone or computer close to the recorder may  
also cause interference. Confirm the interference isnt acoustic born  
by recording with a different brand of recorder. Ive noticed with some  
mics if the connection from the backplate to the FET has solder flux /  
in general isnt clean the FET will produce broad spectral 'pops'. Do  
you notice the low freq interference in all locations ?

-Mike



On Apr 6, 2009, at 4:58, John Hopkins <jhopkins at tech-no-mad.net> wrote:

> Hey folks -- I've been using a zoom H4 for a couple years now, and  
> have
> been suspicious how a non-mechanical recording device -- in a really
> quiet place (for example the Sonoran desert of western Arizona) -- and
> the wave form of a short recording of a passel of birds in a mesquite
> tree at dusk shows a cyclic 3-sec repeating pattern which seems to be
> very low frequency something (sorry, don't have a spectral freq  
> analyzer
> on my machine).  I uploaded a screen shot of the waveform and a wav  
> copy
> of the file -- any feedback?  Has anyone else experienced this with  
> the
> H4?  I've seen it before on the files when recording in really quiet
> places, and of course I suppose the best solution is probably a few
> thousands spent in better field recording equipment, to be sure,  
> but...
>  what could be the cause?     In this instance I was not hand holding
> it, it was on the ground in a stable place, and essentially no wind.
> There is also a higher-pitched whine as well, faugh!
>
> the sound file: http://neoscenes.net/09-03-092_birds.wav and a screen
> shot of the file in Peak showing the approximately 3-second repeating
> patterns http://neoscenes.net/09-03-092_birds.jpg
>
> cheers,
> John
>
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