resilent channel on soffit? (1 Viewer)

[RichV]

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I've put resilent channels on the joist (2x10s) that directly link to the floor above. Should I do teh same for the soffit that is not directly attached to the joist?

 

[soundprogress]

You really asked a good question. Normally, I'd say no. I don't know anything about your decision on noise isolation and each room needs to be looked at thoroughly. Please keep in mind, noise isolation is a tricky thing and almost everything gain can be lost in the details. How's that for being positive!! Here are some things to consider.

The soffit framing is decoupled to the room, except for the wall and ceiling connecting points. You'll may have some noise issue at the intersection of the soffit and the ceiling. Sometimes that solid connection has no noise value and sometimes a lot. If you want a similar noise value, keep in mind resilient channel gets you 3-5dB more >100Hz or so, add resilient channel to both the top and sides as you've done on the ceiling (space from channel to intersection). Use two layers of sheetrock and acoustical caulking in the sheetrock joint.

I'd be concerned about FLANKING NOISE . I don't see any solid wood blocking or other material preventing noise from entering the sidewall or the soffit through drywall and moving up or out to areas you're trying to protect.

Also, if the ducting is plastic and not steel its vulnerable to noise both leaking in and out, breakout noise. That would be a problem if that duct is a supply or return into the room. Noise would bleed out into the ceiling and wall joists.