> I did some searching online but couldn't find details on whether high sen=
sitivity is artificially amplifying the signal or not with the PCM-M10,
Charles,
The signal level at the mic diaphragm is very small and needs to be
amplified quite a lot before it can be recorded. Unfortunately no mic pream=
p
is perfect and the best we can get in practice is 12dB or 14dB equivalent
noise over the thermal noise of the air itself which is a whole new ball
game except it is taken as 0dB sound pressure level or 0Phons.
This amplification is not "artificial" but essential, but the question is
how much? Up the bell of a trombone or near a drum, we can get something
like 120phons, so mic noise is not a problem, and we need to drop the gain=
before the recorder or mixer overloads. This what the "low sensitivity"
setting is for when mic noise is then not a problem anyway. The loudest
audible noise will then probably be the recorder preamp noise drowning out=
the mic noise.
With noisy wildlife we are up against overloads versus mic noise, but not
usually at the same time.
For a lot of wildlife recording at very low sound levels, mic noise becomes=
audible, and the last thing we want is to add more noise in the recording
chain to the mic noise which is always with us, like the poor.
> I'm a little confused by your statement about maximizing microphone hiss.=
Can you please elaborate?
You can't lose mic noise but you can avoid adding to it and this is why -
when listening from the end of the recording chain - the most audible
_system noise_ you hear should be the electronic mic noise.
> Very interesting, I'll have to try the dummy mic test. I picked up a used=
ME66 and I see that the impedance is listed at 200 ohms. Would I simply st=
ick a 200 ohm resistor between pins 1 and 2 on the XLR adapter?
Yes, except it is XLR pins 2 and 3. Pin 1 is ground.
I'm not going to go into the "optimal noise impedance" of a mic, but I
quoted 2000hms as that is what many preamps present to a mic. It is not
critical.
I've given you a bit of a problem here as you will need to compare the nois=
e
as heard with a resistor with the mic hiss. This is where my "pile of
bedclothes" test comes in. Forget the house rumbles and listen for hiss.
If you send me recordings of a few seconds with the mic and resistor at the=
same high gain setting which doesn't overload with the rumble noise of the=
house (put a bass cut in) I'll see if I can talk you through it.
David Brinicombe
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