HVAC duct/other items touching inner & outer frames...

I've recently had a problem with a wall in my vocal booth. I think I have a solution, but then I saw where my HVAC return trunk/duct rests on the outer frame sole plate. The inner frame won't touch the outer frame, but the HVAC return trunk will most likely touch both. Would surrounding the duct/trunk with rockwool (except the grill opening) inside & around the inner AND outer frames help with decoupling? (If this is a decoupling problem) I was wondering about items such as HVAC duct/trunks, pipes etc etc that pass thru and touch, connect or rest on both the inner and outer frames. Would this jeapordize the decoupling procedure, or is the decoupling STRICTLY for FRAME touching FRAME only????? Thanx!

What is your problem? What do you experience. And decoupling is for everying, walls, ducts, windows, doors etc. Adding a piece of flexible duct in between walls would do the trick. IF flanking is your problem.

Hey Ro... No problem "yet". I have not constructed the inner frame for the wall in question. (Inner/Outer wall with HVAC duct/trunk). In order to have the duct/trunk NOT touch the outer frame, I'll have to move the duct/trunk and do some cutting on the outer frame with a reciprocating saw. From your response, since anything touching the inner AND outer frame can jeapordize the decoupling procedure, I think a re-check is in order. Thanx!