Hi I recently purchased the Sony sa-wm40 after reading so many reviews about it being one of the best budget subs. However, Im having a problem with it. For some reason, when I set the cut-off at 50 Hz it BARELY picks up anything. When the cut-off is set to 170 Hz it gets good bass but not very deep at all. Can this be because of my amp? (sony STR-DE485) Help? Thanks a lot!