Loving my HPF it's giving me more headroom less rumble and a better cut in the mix. All super. However on the occasions I use a distortion (not a big fan but needs must) if the HPF is on it sounds like a nest of angry wasps wants to escape from the tweeter. Tweeter is set really low and this happens with all three of my cabs with tweeters and all amplifiers. Admittedly the bas Muff I use is not a high end pedal but prior to the HPF it sufficed for the occasional song it gets used for. Any solutions? HPF is currently first in the chain. I'm going to buzz off now.....bzzz