i finally got my subs hooked up last night. and plugged in a new movie but im not getting what i thought i would get from the lfe source on my h/k. each of my subs is an 8" that i have tuned the cabinets to about 40hz, with about 200 watts going into each one. with the sub adjustment turned up on my h/k to about 6 i still only get just a slight rumble not the bone crusher i was expecting. any thoughts?