This EQ foot pedal will clean up your portable PA system sound if you haven't got much EQ to work with. The key here is the frequency bands of the foot pedal, which represent the most common feedback areas while smoothing out the 'boxy' sound of flat lower mids. Keep this in your breakout kit just in case (this is for portable PA's without subs, but you can always use any mixer EQ to control bass response. THIS WON'T SOLVE ALL PROBLEMS, SO DON'T ATTACK ME FOR SUGGESTING IT!