Well, after a lot of testing, measuring levels into and out of the three
recorders I have (Marantz 670, Sony MZ-NHF800 minidisk, and SD722), I have=
concluded that the simplest test is just as informing as the full battery o=
f
test that can be run without specialized equipment.
The simplest test: Get a 150 ohm resistor, place it across the mic input
(pins 2 & 3 in an XLR, or between tip and sleeve for a miniplug), crank the=
levels all the way up, and record. On the computer, do a 20-20k filter, and=
measure the level in dBrms (relative to a sine wave). Report that value. If=
you don't have a program to do this, send it to me and I'll do it.
The complex test starts with the first one, then you calibrate the
full-scale level by a series of 1000 Hz tone recordings at different levels=
.
In the end the first test tells you all you need to know. It seems that my=
three recorders all have 0 dBFS about equal to 0 dBu (+/- 4 dB) when the
level control is all the way up.
Therefore, the simple test gives a good measure of the practical EIN and
S/N. You also need to know the preamp gain to judge how 'sensitive' your
recorder might be.
These tests are not good for matching a mic to a preamp.
Bruce Wilson KF7K
http://science.uvsc.edu/wilson
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