At 1:58 PM +0200 9/4/08, Juan Carlos Blancas Avil=E9s wrote:
>hello,
>
>when recording with sennheiser mkh 30/60 in empty rooms,
>very quiet nature ambiences or with a high gain preamp setting
>(pro grear) i listen clearly and see later in the RTA a strange emphasis
>noise curve from +-5khz to 20khz ...
>
>this happen the same way to both mkh, but not at all to any other
>of my mics ... any thoughts? maybe mkh doesn=B4t like silence?...
>
>i=B4m also asking directly to sennheiser germany for curiosity...
>spanish sennheiser tech service says that my mics are calibrated
>but nothing more...
>
>thank you and best regards,
>jc
>
>pd. rough test -> emptiness studio room -> mkh60 (all switches off)
>vs rode nt1a-> both digital preamp -> protools -> waves paz
>analyser ->
><http://homepage.mac.com/coeval/filechute/>http://homepage.mac.com/coeval/=
filechute/
>HissMKH60vsRodeNT1a.zip
>
Hi Juan Carlos--
Interesting question. I'm not sure why the noise
performance is as great as your test suggests. In
the absence of high frequency sounds, as with
your quiet room tone test, higher self-noise
typically produces more audible "hiss." According
to the manufacturers, the NT1-A has a self-noise
of 5.5 dB(A) and the MKH-60 is rated at 6dB(A).
If these numbers are correct, there should be
little difference in the amplitudes of the noise
after the playback levels are matched. The tonal
character of the self-noise (the frequency
distribution) can make similar amplitudes of
noise sound quite different; perhaps this is
playing a role? The frequency response of the
NT1-A is much greater under 30 Hz than the MKH
and this often accounts for much of the NT1-A's
total amplitude when recording quiet places. You
might try filtering to remove the frequencies
below 40 Hz from the NT1-A's signal then place
both recordings in a mix session and match
playback gain. That's all I can think of at the
moment. Rob D.
--
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