Connect the “Main out” left and right input of the mixer to the left and right “Input” of the EQ. The mixer should have all microphones and instruments running through it. Connect the left and right “Main output” of the EQ to the left and right “Input” of the power amp. The main amp should connect to the main speakers.
Make sure that the volume is all the way down on the EQ. If it's not automatically powered, power on the EQ. Play a CD or audio sample and slowly move up the volume sliders on the EQ and the mixing board. Place all the EQ sliders at the halfway point; this will start you with a flat base sound.
Slowly move up the sliders from right to left until you hear feedback. Feedback means that you need to move the slider down a notch. Speak over the microphone to test the “Monitor EQ." Move the sliders from left to right -- high frequency to low -- until you hear feedback. When you encounter feedback, move the slider in question slightly back down until it stops.
Play live instruments, such as guitars, drums and keyboard, and adjust the EQ from left to right. High frequency settings will cause loud instruments, such as guitars, to peak and cause feedback.