Paul Jacobson <> wrote:
> Yes true, but then you are talking oranges and apples when comparing
> with other recorders. I've been looking at posts on the HDP2 and to
> suggest that it has woefully low gain vs the 722 doesn't stack up.
Yes, when I measured the absolute input sensitivities (the dBu values)
of the various recorders, it turned out that the gain specifications
reported by the recorder manufacturers are based on very different
definitions.
For instance, TASCAM reports a "maximum gain" of 46.2dB for the HDP2.
It seems that they defined the "gain" as the adjustable gain range,
which is the difference between Trim min and Trim max (-13.8 dBu --
Message: 60.
Subject: 0 dBu =3D 46.2 dB).
Other manufacturers seem to report the gain of the operational
amplifiers (calculated from the ratios of the resistors that determine
the gain) that drive the A/D converters. However, this does not take
into account the absolute input sensitivities of the A/D converter
chips that vary depending on the specific models. For instance, the
A/D chip in recorder A might produce 0dBFS at an input voltage of
Message: 4Vpp.
Subject: However, another A/D converter chip in recorder B might only
require 2Vpp for full scale. So, comparing the gains across different
recorder brands does not make much sense and one should use the
absolute input sensitivities specified in dBu or mVrms instead.
Regards,
Raimund Specht
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