- If you have a tone generator, connect the output of the generator to the “Messeingang” (test
input) and have the microhone connected to a microphone amplifier with phantom power.
Adjust the level of the audio generator until you hear distortion. (The best signal to do this
test with, is a low distortion sinewave.) At the moment you hear distortion, turn the multiturn
trimmer on the audio PCB until the distortion gets lower or disappears. Increase the level of
the signal you are feeding into the microphone circuit until the distortion is again audible, and
try again to find the point where you get the lowest distortion in the output.
Take care that you don’t overload the input of the microphone amplifier you are using!!!
You will find one sharp point, where there is a ‘dip’ in distortion. Leave the trimmer
potentiometer at this point.
- If you have a tone generator AND and oscilloscope, you can repeat the previous procedure
but instead of listening to the signal, you oberve the output signal of the microphone
preamplifier. Adjust for the point where you get the lowest distortion at the highest output.
Note: because the microphone body is open while performing these measurements, there is
a chance that the circuit will pick up some mains hum.
When the calibration is finished, you should now have a working microphone.
