I was with my friend George Bischoff who was the main designer of Scaena speakers at Harry Pearson's years ago. The Scaena were line sources with planar tweeters and dynamic mids. The woofers were powered modular 18" woofers with equalization(actually they rolled off from 180 Hz but were rolled in about 65Hz and equalized flat to about 16 Hz and yes it took hundreds of watts). I believe Harry's set had 3 sets of bass modules.
Anyway we were playing a cut from a CD with music from the sound track of a movie called Lost World. The cut we used according to Harry had a real volcano in the trach that went down to at least 16 Hz. Harry liked loud. And as the cut played I looked at Harry's and my friend's eyes and they were like saucers. I could tell they were waiting for flying woofers. But all we got was tons of very tight loud bass.
I got a copy of the CD and have tried it on multiple systems that claimed they went DEEP. But nothing, so far, has come close.