> I just measured the iRig Pre this morning as well. I got and EIN of
> -112 dBu 20 Hz-20KHz unweighted (-114dBu A-weighted) with input
> terminated at 150 ohms.
Thanks for the confirmation, Rob!
There is one thing that might explain the differences observed by Marco bet=
ween the iRig PRE and the ART Phantom II Pro:
The iRig PRE internally probably subtracts the two output signal rails (+ a=
nd -) of the balanced microphone from each other and outputs the difference=
of both at its single-ended output. So, this is obvioulsy a perfect conver=
sion from the balanced input to the unbalanced (single-ended) output.
If one however connects the balanced output of the ART Phantom II Pro to th=
e single-ended input of the SONY PCM-M10 through the XLR pins 1 and 2 only =
(leaving pin 3 open), then the output signal level (as seen by the single-e=
nded input) will be reduced by 6 dB because the other rail is not being use=
d. This would mean that the effective sensitivity of the microphone is halv=
ed (from 20 mV/Pa to 10mV/Pa), which would in turn increase the demands to =
the preamp and may increase the overall system noise floor.
For a mono recording setup, there would be a relatively simple way to impro=
ve the final signal-to noise ratio by about 3 dB:
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