At 6:48 PM -0700 5/15/07, David Ellsworth wrote:
>Recording at -40dB saturation would indeed make
>24 bits helpful and even necessary. But why, in
>the first place, is the hardware gain not
>sufficient to bring the signal closer to
>saturation? I don't know, but perhaps giving a
>recorder more hardware gain involves compromises.
>In this case I can certainly see how it would
>make sense to let a 24-bit ADC make up for the inadequate gain.
>
>But if increasing hardware gain is not an option,
>why not implement it at the software/firmware
>level =97 i.e., digital gain? The signal would be
>multiplied after going through the 24-bit ADC,
>and then truncated to 16 bits. Of course, if
>you're already using 24-bit recording and it
>works fine for you, this idea is of little
>importance. But I just thought I'd mention it since it hasn't come up yet.
>
>
This makes good sense to me David-- another 10-20
dB of clean gain with time programmable gain
settings.
The dynamic range with the SD 744T at max gain of
70dB using mkh80/40 mics is well-suited for a
_fixed level_ setting for an over-night recording
of a Wisconsin forest. Louder calls of the dawn
chorus peak within -5 to -1dB. If a bird or
squirrel perches right next to the mics, these
calls will over-modulate. If the 744T provided
another 10dB of clean gain I'd probably use it
routinely to get more detail in the middle of the
night. And better yet, I'd program the gain to be
25 dB lower for the chorus. With Hi-MD, I can
get another 10dB of pre gain and I do use it. Rob
D.
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