Set up the PA system properly. The system consists of the main speakers, which are the ones facing the audience, the monitor, which is the speaker facing the musicians and performers, the amplifier and the mixing board that controls that volume and EQ functions. The monitors should be placed at least two to four feet behind the main speakers. The ideal spot for the mixing board is in the center of the room, but many churches may place it upstairs in a balcony so that is not in the way.
Turn the volume level for the monitors all the way down. Set the treble, mid-range and bass controls flat as well. Gradually increase the volume as the performer sound checks her microphone. Adjust the EQ levels after the volume level is set. Setting the treble, mid-range and bass levels depends upon the individual voices of the performers and the natural acoustics in the church. Repeat the process for all the vocal microphones on stage.
Resolve feedback problems by tweaking and adjusting the volume and EQ levels. Onstage monitors are the most common source of feedback, because the sound is in a confined space. Lower the volume level of the monitors when feedback occurs. Isolate the frequency level of the feedback. Adjust the treble, mid-range and bass EQ levels until the problem is corrected. Lower frequencies tend to cause the most feedback issues.
Ask the performers what they want to hear in their monitors. In addition to the vocals, the musicians rely on the stage monitors to hear each other. Each instrument should be miked or plugged into a direct box. This makes it possible to control the volume level for each instrument via the mixing board. A guitar player on the left side of the stage may ask that a keyboard player on the opposite end of the stage be in his monitor.
Add effects to the monitors. PA mixing boards usually feature a number of effects, such as reverb, delay and compression, to thicken up the sound of voices and instruments.
Repeat the same procedures for the main speakers. Setting the EQ for the main speakers depends on type of music and instrumentation as well as the natural acoustics of the room. Work with the musicians and performers onstage to dial in the right volume levels for the room. For example, you may have to ask the musicians to turn their amps down, or you may have to readjust the drum microphones. Set the sound in the main speakers so that all the voices and instruments are clear and distinct. Too much bass produces a muddy sound, and too much high end produces a thin, unpleasant sound.