Low Batteries

• Replace batteries regularly in a cordless microphone.battery image by Aditia Patria Warman from Fotolia.com
  
  A new battery will start to lose the ability to properly power the microphone after about four or five hours of use. As the battery loses power, the signal from the receiver to the transmitter will break down and cause audio interference.
  
  

Transmitter Placement

• Avoid setting up your microphone's transmitter near or behind any objects or obstacles. There should be a clear pathway from the transmitter to the receiver. Solid objects such as metal podiums, chairs and furniture will block the microphone's signal and result in a humming noise.
  
  

Know Your Spectrum

• Television stations can cause cordless microphone interference.antenna image by Pali A from Fotolia.com
  
  Check the back of your microphone's transmitter. Most cordless microphones operate in the UHF spectrum. This is the same UHF spectrum that television stations use to broadcast their signal. Your cordless microphone can pick up a hum due to interference with a television station. Try searching for another channel to avoid interference.