At 1:53 PM -0800 2/17/08, Eric Benjamin wrote:
>Rob D. wrote:
>> Is it possible to measure the noise of the 3.5mm external mic input?
>I'll get right on it.
Great! And if you can locate the Rolls phantom, a quick subjective
listen with your mk2's would be very informative. This would check
for anything going on with the PIP input.
>
>>How much effective gain does the pre have?
>Now that's a good question. I've been puzzled for some time about
>how to express such a thing. If there's a standard way to do it,
>please let me know.
>
>In the absence of that, I was thinking along the lines of dBFS/dBV.
>That is, if a -40 dBV (10 mV) signal produces 0 dBFS (that is to
>say, full scale) in the recorder, then the input has a gain of 40
>dBFS/dBV. A more sensitive input, or one with the mic input turned
>up higher, would have a higher number.
>
>What to do you think?
At least one using the H2's "H" sensitivity setting, "-40dBm." -40
dBV sounds workable if you think 10mv approximates the minimum levels
nature recordists typically encounter. Rich Peet and I were comparing
four mic pres the other day. With Rode NT2000's (16mV/Pa), we noticed
that two pres spec'd with "60 dB max gain," were producing peaks from
rural daytime presence in the -39 to -42dB range (96dBFS) if that
helps. Rob D.
>
>Eric
>
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