It's really not a fair comparison...the 15A was seeing about 1kw, and the XXX is getting about 2kw. The box is a lil small for the XXX, about 3 cubes tuned to 32 hz. I've only had about a half hour of play on the XXX...only thing I can say is it gets a good deal louder than the A did (this is probably due to the power increase). So far, the XXX sounds a little more natural and seems to blend a little more than the A did, but both are excellent drivers. I need a little more time to play around with the XXX to really compare them, but so far, I'm really diggin the XXX //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif