Wireless Microphone Problems

UNADJUSTED TRANSMITTERS

PROBLEM: As good as it is, analog wireless audio transmission has limitations imposed by the inherent noise and limited dynamic range (about 50 dB) of FM transmission. To overcome this, most wireless microphone systems typically employ two kinds of audio processing to improve sound quality. Pre-emphasis is applied in the transmitter (with corresponding de-emphasis in the receiver) to improve the signal-to-noise ratio. A compressor in the transmitter and expander in the receiver can increase the dynamic range to more than 100 dB. This makes it important for audio levels to be set carefully. If the audio level is too low, hiss will be audible. If it's too high, distortion may result.

SOLUTION: To get the best sound quality, the transmitter's input gain should be adjusted so that the loudest sound level that will occur produces full modulation but not distortion.