Knowledge

Almost every wireless microphone system has an adjustment on the transmitter that is called a “Gain” adjustment, which often confuses users. This setting should really be called a “Deviation Control”, but that would more than likely confuse users even more. The problem with calling it a gain setting, however, is that the end user attempts to use it to set their overall audio level – not what the control is designed to do. After all, wired microphones do not have a gain control and the mixing board or amplifier must be used to control the audio levels.

The gain setting is unique to wireless microphones and is used to maximize the signal-to-noise ratio and dynamic range whether it is used as a podium microphone, close talking vocal mic, lapel, headworn, or even guitar or instrument. Frequency Modulated (FM) radios transmit audio information as changes in the carrier frequency. So, in the operation of a wireless microphone system, the greater the changes in frequency (deviation), the better the signal-to-noise ratio will be. So, if the system’s maximum deviation is ±40kHz, we want the loudest level input into the microphone to generate 40kHz deviation. With the gain set above that, we would be clipping or distorting the maximum input and if it is set too low, we are not getting the clearest possible signal.

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