OK, after reading these comments, and being a certifiable Advent freak, I would make the following comments:
Large Advents may not be the best speakers of all time, but I've never really heard anything I like (much) better. At todays prices (or when they were new for that matter) they are the best value in the world.
The bass kicks serious ass. Tight, accurate, and they go as low as many subwoofers. I'm listening to Quadrophenia as I write this, and John Etwistle's bass is just stellar.
I have stacked Advents in the family/media room, and I think that it helps the frequency range. In other words the rolloff is extended by doubling up the drivers. I am told that in a stacked configuration, the freq. range is more like 30-18,000, which nicely covers the entire range of music, and the human ear.
Rock On. Booher, out.