--- In Walter Knapp <>
wrote:
> > * The sensitivty of the Rode NT3 is 12dB(A), about 4dB less
than
> > some other mics with the same self noise rating I regularly use.
> > Whenever the record gain is high, its easy to hear this
difference in
> > sensitivity because its translates into 4dB? of additional noise
when
> > the sound is played back at final mix level.
>
> This is a whole 'nother aspect of the self noise equation. In what
I
> said, mic sensitivity was more or less ignored. But it has a
bearing in
> mic choice vs self noise. The better the mic sensitivity, the less
you
> will be increasing gain to get the meter reading you want, so the
less
> you will be lifting the noise floor.
Walt,
I'm not sure if I understand correctly what you mean. The inherent
noise of microphones is always specified in absolute sound level
figures that correspond to a certain absolute environmental sound
level. The absolute sensitivity of a microphone does not necessarily
influence it's noise performance, as long as the additional noise
introduced by the required pre-amplifier is low compared to that of
the microphone. Most state-of-the-art professional pre-amplifiers
introduce much less noise than the microphone. I recently tested my
MKH 60 with the pillow method you suggested. After replacing the
microphone by a dummy resistor, the remaining noise floor was much
lower (even at high gain settings).
Nevertheless, a high sensitivity is of course a good property of a
microphone, especially if you use a relatively poor (noisy) pre-
amplifier. When I compare my old Sennheiser K3/ME80 (5mV/Pa) with
the new K6/ME66 (50mV/Pa), I can not find very dramatic differences
in their noise performances. The lower output level of the old one (-
20dB) can be compensated by adding more gain on the pre-amplifier
without any loss of fidelity. Listen to this recording of a European
Nightingale made with the outdated K3/ME80:
htttp://www.avisoft-saslab.com/sounds/ntg.mp3
The deviations between microphone sensitivities may be caused to
some extent by different internal electronic circuits. It is often
not very important, whether the amplification takes place within the
microphone housing or in the pre-amplifier of the recorder. However,
especially under critical circumstances, higher microphone output
levels are less sensitive to small noise voltages (e.g. hum)
entering the microphone extension cable.
Regards,
Raimund
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