I think I understand, but let's walk through it:
- Baffles are needed on both sides (ie, on the inner and outer leaf)
- inner baffle and outer baffle must be decoupled from each other
- the boxes mass should match the leaf mass
- flow should slow down at the exit into the room
Now I don't recall reading that the baffles must be exactly at where the air enters or exists ... maybe I missed this? I was under the impression that the baffles must be decoupled from each other, and each box is coupled only to the given leaf (inner or outer).
In the above layout, the boxes are in serial layout due to space considerations ... but they are coupled to separate leaves. The left box is the supply to the room, and is decoupled from the joists. A duct passes through the inner leaf. The right box is attached to the joists (outer leaf), and is not coupled to the inner leaf, or the other box (pipe in the middle is sealed with insulation/caulking, not hard attached).
For the return boxes, same idea. The left box is coupled to the inner leaf framing, then the pipe and outer box is decoupled from that and sitting outside the room.
Here is a closer detail with framing. This is the inner leaf box, penetrating the ceiling drywall. It sits in the joist space, but it is not coupled to the joist (the outer layer of insulation is the decoupler).
This is the outer leaf box. Also in the joist space, but its actually attached to it, so the outer leaf. The joining pipe form the inner leaf box is decoupled from this box, again with insulation at the joint:
Does that make more sense, or am I still out to lunch?
Thanks for reviewing and chiming in!