mine is from my car audio days when i was in to db drags
i have a 84 supra that had 4 soundstream spl mules one of the frist spl subs and 3000 watts they hit so hard in the 40-60hz range that i had buddys jump out of my car when i put a 50hz tone on at 150+db
but when i played tunes they had the most kick bass i have ever heard it was so loud that you could not read the plates on the car in front of you at a spot light
some day i might get back in the spl game but its a lot of work and i dont really have the time right now
i am to busy playing with my home stuff
in the spring i am going to redo the set up in my work truck i hope i dont get bitten to bad by the caraudio bug this time around