I heard first at avsforum member's luke kamps house on his HSU VTF-15H with a 16hz tune in a 1500 cubic foot room on the incredible hulk cop car scene. Previous to that I've always played around with more traditional retail subs, My Infinity HPS-1000 pair, My Jamo D7Sub pair, a JBL Sub, a few nice expensive velodynes, a couple PA 18's, a TON of car audio stuff, a DIY sealed ottoman sub with four 15's that was more college frat cool factor than actual design intelligence, and a bunch of other low budget junk. The HSU gave me a forced grin that I just couldn't shake I think it was my first exposure to a true subwoofer, or at least my first exposure to great subwoofer in a small room that complimented its capabilities!!! I'd like to bring one of my Infinity HPS-1000 over to Luke's house for some testing to see how it does in Luke's room now that I have one working again! At any rate we rewatched the same scene with the HSU in the 22hz tune. With the 22hz tune -- I felt a bit of been there done that, and asked if we could put it back in the 16hz tune. We did and we watched it again -- my unstoppable smile was back! I've not found that very bottom inaudible octave to do anything extra for me --- but down to 15 or even 20hz with a good strong flat frequency response is phenominal! There is gads of difference between most of these retail subs that say 25 or 30hz -150 with +-3 or +-6 db and a sub that actually measures darn near flat to 20hz or a bit lower!