[KJDJ]

First rule for sound systems is the amp is the last thing you turn on and the first thing you turn off.
Why doyou have the feedback destroyer on the whole system?
You need to put it in line with the mic only.
The way you have it set now when it filters mic feedback it filters your music too.
If you can,send the destroyer back and get the Shark it can be set mic in mic out level thus put in line between the mic and mixer.