My couch used to shake, rattle and roll when I had my 600 set to 80 Hz and by-pass (read my post on bass earlier today). But with the changes I've now made, I feel "punches" rather than "booms".

I'll give you an example. When watching LFODH's apartment shooting scene in the beginning, at 80Hz I heard a very "thick" rat-a-tat from the machine gun and what I felt was something boomy all over me and around me. But at 40Hz, I heard a totally realistic machine gun staccato and felt that sucker right in my left butt cheek through my leather couch \:\) . In the U-571 depth charge scene, at 80Hz my whole couch shakes. But at 40Hz, I feel the sharp impact of every blast. And when one of the charges at the start of the scene falls in the water, I very clearly hear the sound of water being displaced and then getting sucked in as the barrel submerges. Sort of like what you hear as you finish off a can-opener in the water. But with 80Hz, that subtle yet oh so cool effect vanishes.