It turns out that yes, one can use the standalone Aria player with the Mac version of BIAB, via the IAC bus or BIAB's Virtual Output -- but not in the same sort of way that one could seamlessly use Bandstand. Garritan's Jazz and Big Band provides high quality sounds that cover most of the GM set. But while Bandstand would accept patch changes from BIAB, it appears the Aria player does not. So when one selects a style in BIAB, one must configure half a dozen or so channels in the Aria player for the appropriate patches. Select a different BIAB style, and configure half a dozen channels again -- and not just for the appropriate patches, but for levels and other settings, to create a reasonable ensemble. And of course, if one has set up a song in BIAB to change patches at a certain bar, there's no way the Aria player will do that. I'm not really complaining about the Garritan/Aria product; it's not a GM synth, and I shouldn't expect it to be. But it sure would be nice if there was something out there that really worked with BIAB, and sounded better than Apple's DLS sounds...