0:51
Electric induction microphone - 60 Hz ground hum.
0:31
Test tone at 50 hertz or Hz
0:31
Test tone at 100 hertz or Hz
0:30
Test tone at 440 hertz or Hz
0:30
Test tone at 1000 hertz or Hz
0:31
Test tone at 30 hertz or Hz
0:30
Test tone at 500 hertz or Hz
0:30
Test tone at 250 hertz or Hz