when i play through my bands pa i get this chirping sound on all of my notes above the A string. this happens any time i run through this pa, beringer board qsc power amp with jbl speakers. my main bass is passive though it does the same thing with my active bass. this happens on every channel on the board through either a direct box, digitech proccessor, direct out from super redhead or ampeg b3. this chirping sound is very annoying and kills my whole vibe. anyone have a clue to cure this?