Thanks Tim. I'm thinking about experimenting with that F-99B (seems a
shame to waste a fairly expensive mic) but it means cleaning up my shed
and workbench first - something I've been putting off for a couple of
years!
I have the first two of those requirements, but time is in short supply.
The circuits in the article referenced by bw up-thread are one starting
point, if I do make the initial effort.
http://www.hobby-hour.com/electronics/computer_microphone.php
I could even avoid the spring clean by doing some bread-boarding here at
my PC. ;-)
If you are going to build a preamp anyway, you may want to
connect it to Line In instead of Mic In. Although Mic In is
about 10 times more sensitive (say, 100 mV vs 1V
full-scale), it may be more than 10 times noisier. It also
has (in the sound cards I've tested) a reduced frequency
response of about 9 kHz or so, instead of the full 20 kHz.
(That's not a problem for the originally-intended use with
voice, probably even a good thing.)
I've also seen some sound chipsets that have strange
behavior on Mic In, which might be related to the reduced
frequency range. Looks like it is sampling at a reduced
rate (maybe 18 kHz instead of 48 kHz) and then using sample
rate conversion to get back to 48 kHz equivalent. But there
seems to be minimal anti-aliasing on the original
conversion, so high frequencies (above 9 kHz) wrap back down
with hardly any attenuation. This would be a Very Bad Thing
for music recording.
Mic In is always mono-only, with the Left (white) line
carrying the signal. The Right (red) line is only used for
phantom power for the electret's built-in FET preamp, which
I seem to recall is typically 5V through a 4.7K resistor (or
something like that). But I think some (most?) setups may
apply that directly to the Left. That bias doesn't cause a
problem since the sound card input is AC coupled.
Best regards,
Bob Masta
DAQARTA v6.02
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Scope, Spectrum, Spectrogram, Sound Level Meter
Frequency Counter, FREE Signal Generator
Pitch Track, Pitch-to-MIDI
Science with your sound card!