Dear SVS PB10-ISD owners out there, I've been playing with placement and SPL readings. Anyone else experience the spike from 40 Hz down to god knows what. Crossover set to 60 Hz, I notice a slight dip from 60 Hz to 40Hz. It probably is placement, or my small room, but I pushed the sub out of the corner already. I'm thinking maybe turn down gain on sub...but that would probably worsen the 40-60 hz dip. Any other suggestions?