Reply by Vincent Nocito

Check to make sure your blade is dead on at 90 degrees also make sure the insert is absolutely level with the top of your saw (not canted). You can also try running a piece of sandpaper that is wrapped around a thin piece of wood slightly smaller than the kerf of the sawblade through the insert. It helps widen the clearance just a smidge and quiets things down. If there is still noise, put a dial indicator on the blade and check to make sure there is no blade warp or arbor run out.