Today I want to share a few tips on how to reduce microphone hum. Since Microphones and microphone cables are especially sensitive to hum pickup because of the great amplification needed for microphone level signals (few millivolts). The humming can be caused to microphone signals because of ground loops and because of induced noise. Here are some tips to minimize microphone hum pickup:
* Use low impedance microphones (150-6000 ohms). All modern recording equipment and mixers are designed to work with low impedance microphones.
* Use microphones with balanced outputs (three pin XLR connectors). This kind of microphones picks up less hum than unbalanced microphones.
* Routinely check microphone cables to make sure that the shield is connected at both ends.
* Check that the screw near the XLR connector on the microphone is securely screwed in place inside microphone handle.
* Do not connect the ground on XLR connectors to the shell of the connector, because ground loop hum may occur if a grounded shell touches a metallic surface.
* Do not ground microphone junction boxes or snake boxes except through the cable shield.
* DO NOT PLACE MICROPHONE NEAR METALS…. I learned this the hard way, trust me.