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Re: Fostex FR-2LE vs SD 722 (was 722 vs MixPre)

Subject: Re: Fostex FR-2LE vs SD 722 (was 722 vs MixPre)
From: "Rob Danielson" danielson_audio
Date: Mon Mar 23, 2009 10:55 am ((PDT))
At 8:55 AM +0000 3/23/09, Raimund Specht wrote:
>--- In
><naturerecordists%40yahoogroups.com>=
m,
>Rob Danielson <> wrote:
>
>>  When I first listened to Curt's test with my aging ears on speakers,
>>  I didn't notice any difference between the two recorders. When I made
>>  a sonogram the next morning to see if I had missed anything, I was
>>  shocked.
>>
>>  To better reveal the performance differences, I edited the ticks so
>>  the edit point falls in the middle of the room presence between ticks
>>  4 and 5 (rather than immediately before 5). The additional clarity in
>>  the lower mid-range and reduction in hiss in the SD 722 is pretty
>>  apparent. The uniform noise added above 9K Hz by the Fostex is
>>  definitely worth further exploration. Curt is conducting a similar
>>  test again; perhaps others with FR-2LE's might want to see if they
>>  can duplicate these results.
>>
>>  1.8mb QuickTime movie plays in a loop:
>>  <http://tinyurl.com/c8lvty>http://tinyurl.com/c8lvty
>>  or
>>
>><http://www.uwm.edu/~type/audio-art-tech-gallery/pages/Olson-fr2le-sd722_=
Sor_Lrg-present.html>http://www.uwm.edu/~type/audio-art-tech-gallery/pages/=
Olson-fr2le-sd722_Sor_Lrg-present.html
>>
>>  Rob D.
>
>Hi Rob,
>
>Yes, I also noticed the increased level of noise above 9 kHz in
>Curt's test file, certainly on the left channel. It seems to be some
>kind of a noisy oscillation (there is soft peak at 16 kHz).
>
>I have never seen such an effect on my own FR-2LE. It might be that
>it is just a noise signal originating from another electronic device
>that was present in Curt's test room (which however is unlikely) or
>that it is perhaps a problem of the (individual?) FR-2LE in
>conjunction with the AT3032. I have tested my own unit only with
>Sennheiser K6/MExx and MKH60 microphones (and 150 ohm termination
>resistors).
>
>Regards,
>Raimund
>
Hi Raimund--

Thanks for the insights and hope. Yes, the sonogram in the movie is a
mix of both channels. It did occur to me that I should check the
individual channels but I forgot.

Split sonograms, left mic on left:
https://pantherfile.uwm.edu/type/public/images/olson-fr2le-sd722_Sonogram_S=
plit%20L%26R%20.jpg

As the > 9K Hz noise is present on both channels it can't be unique
to the left 3203, I guess it could be in the pre and worse on the
left channel.  It could be environmental noise if only on the left
side of the room and pretty close to the left mic. That does seem
unlikely but ya never know,..

Any way, we'll have more information as Curt is testing again and he
can confirm there's not >9KHz environmental noise in the room with a
sonogram check before he starts.Curt,  you might also want to filp
around the mics and check their symmetry with sonograms as you start.
Rob D.





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