The problem is apparently in the way that Band In a Box 2009.5 MAC signs in to its Midi settings. After emailing with Rob there, we found this fix though it is not very satifactory:

The first time I run Band In A Box and whenever I open a song, I get no sound out of the Tascam US-1641. I always have to open the menu "Select Midi Driver or DLS synth... " and select the Apple DLS Synth. Then I have to click OK to close it or I get no sound. I have to do this EVERY SINGLE TIME I open a song file in BIAB- EVEN IF the "Apple DLS synth" is already selected in the menu "Select Midi Driver or DLS synth... ". This makes BIAB totally useless on a gig.

Band In A Box 2009.5 MAC is not initializing something properly when it first opens.

I am now told I have to pay for the 2010.5 upgrade and there is no guarantee this will even fix it. Obviously this isn't the solution I was looking for. The audio coding is not working right in 2009.5 MAC and it should work. PG won't fix their malfunctioning 2009.5 software. Clearly I shouldn't have to open the dialogue box every time I load a song just to be able to hear it.

Not cool. Boo on PG Music. I'm a BIAB user (and was a beta tester) since the mid 1990's

Matt
Patchman Music

Matt
PATCHMAN MUSIC, LLC
9535 Greystone Parkway
Brecksville, OH 44141

Phone: (440) 740-1288