I have had a Paradigm PDR-10 subwoofer for the past few years. I am using the receiver's crossover (Denon 3805) set at 80Hz. With the subs crossover was at its highest level (150Hz) low-mid bass was missing. I set the sub using an SPL meter and AVIA (even 4 dbs hot!). Now after moving the sub everywhere in the room and having the same problem, i tried lowering the crossover on the sub to around 90Hz. I checked the SPL again and the bass level was down about 15dbs! I raised the sub volume and the mid-bass and low-bass returned! Does this make sense? If the receivers crossover was at 80Hz, shouldn't the subs crossover be at its highest level without any adverse effects? Or could the room/sub mix be causing a peak in the >80Hz frequencies and lowering the crossover "fixed" this problem?