Like the others, I'd look at the cables first. I'm thinking it might
possibly be a severe impedance mismatch. If instead of 150 to 600 ohms the
preamp saw a couple thousand ohms, a capacitor in the preamp would only pas=
s
the very highest frequencies and block everything low. After correcting for
overall volume the highs would be way up.
Thing is, you'd never get a high impedance from dirty connections (or
something) in both mics at once. Your recorder doesn't have a high-impedanc=
e
mic mode, does it? I have the same recorder and I don't recall that functio=
n
being there, and I'll bet a couple thousand bucks you didn't mistake the
line-in for the XLR jacks.
Bruce Wilson
http://science.uvsc.edu/wilson
-----Original Message-----
From:
On Behalf Of Allen Cobb
Sent: Thursday, September 21, 2006 8:24 AM
To:
Subject: [Nature Recordists] sibillance with NT1-A pair
I've been recording on a PMD-670 with a pair of NT1-A large diaphragm
condensers for some time now. Recently a few sessions have been seriously
marred by excessive sibilance, far beyond the capability of any sort of
de-essing in post (which I really want to avoid).
The "esses" are very grossly overmodulating, while everything else sounds
perfectly normal. Some recordings were made with foam shields and others
without, but there were no popping or plosive problems. The speaker or
singer was always at least 18" - 36" from the mics and in some cases even
further, so there wasn't any "wind" reaching the mics. I confirmed the
problem after one blown session by speaking "she sells sea shells by the
seashore" quietly from 24", and the result was horrendous.
I set these particular mics aside for a few months, pending some serious
experimentation to see if it was preamping, PMD-670 switch settings, etc.
Last night, all test recordings showed nary a hint of any sibilance issues.
Both mics sound pristine, and none of my vocal hissing and spitting produce=
d
any distortion at all.
So now I'm wondering what happened (to the mics, presumably) to produce (or
eliminate) this type of distortion. Temperature and humidity are the only
factors I can think of which might have changed. I realize that large
diaphragms have a reputation for sibilance, but this is a huge range of
performance variation that -- if I can't control or predict it -- makes the
mics pretty useless for recording one-time events.
Any insights, especially into how I might prevent it in the future, would b=
e
greatly appreciated.
Cheers,
Allen
Allen Cobb
http://timbreproductions.com
"Microphones are not ears,
Loudspeakers are not birds,
A listening room is not nature."
Klas Strandberg
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