ductwork!
ductwork is coming along nicely, although it's proven to be a bit trickier than originally planned and won't be done until tomorrow. i snapped a few photos of the work thusfar, but it's hard to get intelligible pictures, what with the maze of wall frames and all. this is the best one i got -- the return for the vox booth:
they're using oval-shaped ductwork for this run, which does an awesome job of squeezing in between the frames. it comes down from the ceiling on the right, makes a 90 degree turn to the left, followed by another 90 degree turn down, and then mates up with the register. these turns will help reduce mechanical and air noise. additionally, they sized the ducts as big as they could for these rooms, which will help further reduce air velocity, and by extension, air noise.
i'm glad that all of the elbows are curved rather than square. this should help reduce air turbulence around those corners.