Hi Curt--
Since it showing up on the line input too, it does make sense to
suspect AD or something unique with the recorders input stage. If its
in the recorder, wouldn't one expect the same results with a
comparable electret like a Sony ECM55B or 66B? Might confirm that
next?
I don't think I hear the same kind of bottoming out sound with the
NT1A's->Rolls->NH-900HiMD that I get with 183-> HiMD (PIP) But, I
could check that. And the NT1A's really put it out below 30Hz
compared to the 183's.
How have you wired up the 183's on the Art Phantom? How would you
describe the performance improvements? Rob D.
= = = = = =
At 5:43 PM -0500 9/20/05, Curt Olson wrote:
>I and one or two others here have reported occasional problems with the
>combination of Shure 183 mics and Sony recorders of various kinds. The
>recorded signal seems to easily "bottom out" or totally break up in the
>presence of high-level, low-frequency sounds (such as heavy doors
>closing or loud vehicles passing by). Further, if I remember right,
>some folks with Sharp recorders have indicated no such problem. About
>10 days ago I had another nasty encounter with this phenomenon, and
>decided it was time to seriously investigate. (The service door to my
>garage is a perfect sound source for this test, guaranteed to "bottom
>out" the 183 > Sony mic input combination any time with little effort.)
>
>When I first discovered the problem earlier this year, I suspected the
>183s themselves. Some conversations with Rich Peet let me to try giving
>the mics more power than PIP provides. I ran them off a 9V battery, and
>more recently off a 12V phantom power supply (ART Phantom II). They
>seemed to like the increased power, but the low-end "bottoming out" was
>still there in every case. I've also been able to replicate the problem
>with Crown GLM-100 E microphones, so that pretty much rules out the
>183s as being the culprit.
>
>I began considering the Sony mic pre, so I ran the 183s off 12V phantom
>power directly into the line inputs of my Sony MZ-NHF800 Hi-MD
>recorder. It still "bottomed out."
>
>Next, I ran the 183s off 12V phantom power into the line inputs the of
>a Lexicon PCM 91 digital reverb (in "bypass" mode) and digitally from
>there into ProTools. Through this pathway, the recorded signal was
>perfectly clean. Then I routed that clean signal digitally out of
>ProTools into a Waves L2 (hardware box) limiter/ADC/DAC (still clean at
>this point) and into the line input of my Sony MZ-NHF800 Hi-MD
>recorder. And there it was, "bottoming out" again!
>
>I inserted an EQ plug-in into my ProTools channel and found that a
>high-pass filter with a 6 db/octave slope and a knee of around 90hz
>pretty much eliminated the problem at the Sony line input.
>
>I'm not trained or equipped to investigate any deeper than that, but
>I'm guessing there has to be a design flaw somewhere in the Sony input
>path -- possibly the final line driver or, more likely, I suspect, the
>low-end capabilities of the ADC.
>
>I've experienced this "bottoming out" phenomenon on my MZ-NHF800
>Hi-MD... and also on my TCD-D7 DAT recorder... and also on my NT-1
>Digital Micro Recorder. So it seems to go a long way back in Sony's
>design history.
>
>One workaround is the Sound Professionals SP-SPSB1S:
>
>http://www.minidisco.com/sp-spsb1s.html
>
>A little pricey, maybe, but I picked one up and so far I'm glad I did.
>
>Any reactions?
>
>Curt Olson
>
>
>
>
>"Microphones are not ears,
>Loudspeakers are not birds,
>A listening room is not nature."
>Klas Strandberg
>Yahoo! Groups Links
>
>
>
>
--
Rob Danielson
Film Department
University of Wisconsin-Milwaukee
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