Actually, this sound system is used in my Church. A 12 channel mixer is connected to the Amp. Now the Amp master volume set to 3.5, Bass around 4 and treble around 6 or 7. So what changes should be made to hear a clear voice than a rough tearing noise through the speakers? Or, is it the problem of the Mixer adjustments? (All 12 channel of the Mixer is using, one for the Keyboard.)