At 7:12 AM +0000 4/1/10, Raimund wrote:
>
>
>Rob,
>
>Please note that I have never measured the EIN of the Sony Hi-MD.
>The -124dBu(A) on my list were taken from John Beale's website.
I aware of that. I think that figure has aged well.
>
>I agree that a list with single broad-band noise voltage figures
>will not always match the subjectively perceived noise level due to
>colorations of both the preamp and the microphone noise floors. A
>better way to quantify these things would be to compare the noise
>spectra of both the preamps and the microphones. I did this for a
>few microphone/recorder combinations a few years ago:
><http://www.avisoft.com/test/noisefloors.pdf>http://www.avisoft.com/test/n=
oisefloors.pdf
>
>Unfortunately, it takes more time to run such detailed tests (and
>measuring microphone self-noise levels in a reliable way would also
>require very special equipment).
>
>I think that it is important not to confuse the equivalent
>microphone noise figures (expressed in dBA) with the absolute
>microphone noise voltages (expressed in dBu). So, the dBA figures
>alone should NOT be used for selecting the preamp. As Paul's Excel
>sheet
>(<http://bit.ly/Mic_Output_noise_chart>http://bit.ly/Mic_Output_noise_char=
t)
>nicely demonstrates, there are a few microphones, such as the Rode
>NT1-A, that are extremely demanding regarding the preamplifier
>noise, while other models with similar dBA specifications are less
>demanding (Sennheiser MKH-60 for instance). So, if the noise
>performance was the biggest concern, then one should prefer a
>microphone with the maximum sensitivity (expressed in mV/Pa).
With recorder's like the FR2-LE, I think it might have become quite
affordable to (transparently) support all mics that are "extremely
demanding regarding the preamplifier noise."
When I weigh both factors. it seems to me that mics with very low
self-noise and sensitivity around 40 mv/Pa can improve end noise
performance with pres starting around -125dBu (A weighted). Rob D.
>
>Regards,
>Raimund
>
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