I can't let mwaegner have all the fun...here's the day's progress:
The steel beam is integrated into the outer wythe:
A view from the other side showing yet another half-finished bond beam:
By the way, the black stuff you see attached to the steel side is a double layer of #30 felt (the kind of stuff you put on a roof under asphalt shingles). Without the felt the beam rang like a bell when you hit it, and I was worried that even if it was embedded in the wall that a resonant frequency could excite it into full-throated song. With the felt, it sounds like I'm hitting a 12"x12" post--no ringing at all. And no fear that we'll have to tear apart the wall when the studio starts to rock and roll.