A common misconception concerning gain staging in a live situation is that the master and channel faders should be set at unity gain during the sound check. In actuality, the faders should be set about 3dB above unity gain. Increase the gain on the input section of the mixer until the meters just start to light red to indicate clipping. If you then return the faders to unity gain, the signal will be nicely situated to be amply loud without any annoying clip lights or distortion to make the crowd cringe when the band hits a peak!