Paul you wrote:
>
> The implicit assumption here is that the 702 has 68dB gain. This is not a=
ctually true. The SD recorders have around 48/50dB gain, rather than 68/70=
dB. This error has arisen because SD measure "input to -20dBFS" rather than=
the more commonly used "input to 0dBFS". Ignoring the "to -20dBFS" results=
in the gain being overstated by roughly 20dB.
Yes, the gain specifications provided by the manufacturers can be confusing=
. The gain of the preamp alone does not say anything because different A/D =
converter chips can have different input voltage ranges that would also aff=
ect the 0dBFS or clipping level.
> Raimund's tests include gain measurements which are measured "to clipping=
", rather than "to 0dBFS". Raimund might like to comment on the level diff=
erence between "to clipping" and "to 0dBFS" but my estimation is that "to c=
lipping" results in 2-3dB lower gain figures? Raimund's "to clipping" test=
s indicate that in high gain mode the DR-680 has 12dB more gain (58dB) tha=
n the SD722 (46dB).
According to my understanding, "clipping" and "0dBFS" levels are identical.=
However, there is indeed a 3 dB difference between the peak amplitude volt=
age and the root mean square voltage of a sine wave. Nevertheless, this sho=
uld have no influence here because signal levels are always expressed in rm=
s levels.
Regards,
Raimund
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