Raimund, you wrote,
>I recently prepared some hints on
>microphone/preamp noise myths:
>http://www.avisoft.com/tutorial_mic_recorder.htm
There you say:
>The S/N ratio is the ratio between the maximum (full-scale) signal
>level (at a certain gain setting) and the inherent noise floor of
>the recorder. Therefore, this figure depends on the device-specific
>input headroom (the level at which the preamplifier or A/D converter
>will be saturated) that is usually of little importance for
>recording soft animal sounds. In other words, the S/N ratio does not
>necessarily tell anything about the noise performance of the
>recorder.
The ratio from full-scale to noise level is "dynamic range." S/N
ratio is usually specified from "operating level" (0 VU), the average
level of the program material, not the peak level. But the terms are
often used imprecisely.
> For instance, the microphone input of the Marantz PMD671 is
>honestly specified with a "poor" S/N ratio of 65dB(A), while the
>M-Audio MicroTrack claims a signal-to-noise Ratio of 100dB(A).
They mean dynamic range. See:
http://www.m-audio.com/products/en_us/MicroTrack2496-focus.html
They specify dynamic range and S/N as the same figure. In digital
audio the "operating level" (0 VU) is a moveable feast,
anyway--anywhere from -12dBFS to -20 dBFS depending on the
application. Inexplicably they quote the S/N as a negative number.
It's obvious they don't know what they're talking about. No wonder
they can't get it right.
>However, a practical side by side test reveals that the PMD671
>provides a significantly lower inherent noise level than the
>MicroTrack2496!
I've been told that the MicroTrack's best noise performance--only
decent noise performance--is using the TRS inputs with the +27dB gain
boost menu setting.
-Dan Dugan
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