Looking back a few pages and the issue of ridged ducts running through a room was addressed, but just to confirm is the conscious to use flex duct where the duct vents into the room? Also, would it be worth it to build a duct muffler or silencer between the take off and vent drops? The goal being to reduce the flanking noise from the theater into the rest of the duct work.
I have an existing ridged duct that vents into my unfinished basement, running parallel between the joists. I’m planning on having the vents in the room ceiling, no extra isolated soffit for the duct work, and I’m wondering if I should replace it with flex duct or do anything else when I extend it. If it makes a difference I’m planning on doing all the recommend techniques discussed in this thread – DD + GG, clips and channel, DD between floor joists, disconnect walls, etc.