How to Test a Microphone:
I’ve seen it many times and still cringe when I see people tapping or blowing into microphones to check to see if they are working. Hitting something is not the best way to see if it works, and blowing into a microphone produces pressure levels that could damage the delicate membrane in a microphone capsule.
The best way to test a microphone is simply to talk into it. That is why you will often hear sound engineers saying ‘One two, one two’. They are not practising something most of us mastered in childhood; they are speaking into the microphone to test to see if it works. Actually, when we say ‘one’, we naturally produce a low vocal frequency, and when we produce the ‘t’ sound in ‘two’, we are producing a high vocal frequency. By saying ‘One two, one two’ we are therefore also checking if the microphone and sound system are responding as they should to different audio frequencies.
Incidentally, when you hear someone testing a microphone saying ‘One two, one two’, listen carefully for the budding comedian nearby who says ‘Three four, three four’. There’s always one!