If you're getting feedback, try these suggestions:
Applies to:
Move further away from the speaker. Microphones and instruments—like acoustic guitars—can cause feedback if they are too close to the speaker
If using a microphone, try talking closer to the microphone or moving the microphone closer to the audio source it is capturing
When positioning microphones, don't aim them directly at the speaker. Try positioning them off axis from the speaker and at least a few metres away from it
If the connected source has it's own volume, be sure that it's not set too loud or too low
Try turning down the REVERB and TREBLE controls