The soffit mount is based on John's diagram
HERE...
What my contractor did was to build them as separate enclosures and then place the entire enclosure into the corner framing (insulating and sealing behind the enclosure and the "triangular" space on the sides)... so they are built-in but not really - they can be removed from the framing quit easily.
Using this separate soffit enclosure idea also has the advantage of being easy to change should I switch monitors in the future - I'm not tied to the framing that surrounds it, I simply have to change the interior of the enclosure and mount it back into the frame!
The control room is 18x12 with the window being something like 5.5x5 or so... the window in the vocal booth is large - 8x5 or so...
The booth itself is 8x11, the two other studios are roughly 15x12 and 13x12...
We managed to maintain pretty close to 8' ceiling height in a lot of places - except where ducting and beams made it impossible. (Yeah, I would have liked higher height - but "ya work wit wot ya got!")
I do like the angled look of where the ducting is framed - it will look cool when painted/finished!
I'm getting anxious to get in there with the gear!
Drywall and flooring should be going down this week, so I should have some "prettier" update pics for John on the weekend!