I used to play regularly at a club in Rochester NY called the Horizontal Boogie Bar which had 4 of the MT4s on a side in their PA (lots of reggae groups came through). They had gone to a hospital auction and had bought these Pickering amps that were used for magnetic resonance imaging and had to be sold off every 4 or 5 years to keep the lab in spec. Each one was 4000 watts and dead flat from DC to light, as they say. It was a profound bass experience in that room.
I've played through a bunch of great rigs, but I think one of the best bass in a room (as it were) experiences I've had was at Red Rocks. There's just something about the way that place sounds. I didn't play my Alembic, but the Starfire sounded wonderful.
The most profound bass experience I've witnessed was probably the Grateful Dead at the Oxford Plains Speedway in 1988. There was a stack of double 18 Meyer subwoofers 1 wide and maybe 4 stories tall on each side of the stage. There were 140,000 people in the area (with 80,000 in the racetrack) and the bass was effortless, quick and insanely deep everywhere.
I've got to say, though, an Alembic pre into a good size power and with a fEARful cabinet (
http://greenboy.us/fEARful/) rivals just about anything I've ever played, perhaps with the exception of Mike Gordon's Meyer rig. It has real bass response, handles a lot of power (mine didn't let out the magic smoke until I experimented with bridging my amp and ended up enthusiastically playing a reggae tune at the end of a long night at Fox Theater with 2200 watts going through it) and weighs about 50lbs. It's also pretty inexpensive if you are handy with tools.
