isolating noise transmission in metal duct work

BrandonHook

I'm about to install a drop ceiling in my basement and use the space as an audio recording studio. The weak link for noise reduction is the HVAC metal ductwork. While in the master bedroom on our 2nd story, I can clearly hear someone whispering from the basement. The only conduit for this quiet of noise source is the ductwork. Should I replace the metal ducts with fiberglass ductboard? Are there any effective "wraps" for this purpose? what are my cost effective solutions? Also, I would like to keep my ceiling as high as possible.

Best Regards,
Brandon Hook
Sr. Acoustics Engineer
Peiker Acustic, Inc.
2870 Technology Dr
Rochester Hills, MI 48309

jmosh

I Use metal duct , but use 1" interior ductliner glued and pinned inside the duct. R6 flexduct for supply take offs and carefully interior line the outlets. Using a little extra flex between the trunkline andthe takeoffs, and making smoe nice soft bends, anything you cando to remove "line of sight" sound transmission and reflected sound transmission. would do .
But short of redesigning the system feeding the studio, thats real all you can do, however that sould be sufficient.

pipefitter636

Remember that if you line the inside of the duct you will lose 2" on the h&w so it will need to be larger. Can you post pics of the area in question(duct suppy and return)might just need to take care of the supplys and returns that feed that area since the main trunk will be in the drop ceiling.