Originally Posted by twochannel
I'm looking for advice on something I'm considering. I'm finishing my basement and would like to use 4 triad ceiling speakers for the .4 dolby atmos/dts:x effects. I have two goals for sound isolation, I'm trying to decrease the amount of sound that can reach the rest of the house. I'm not looking for complete isolation, but enough so that a movie doesn't shake the the upper floors. Additionally, my son's room is right above where the HT will be. I know there is only so much I can do for his room and my goal is to be able to enjoy a sitcom at night without waking him. (not master and commander)
To help with this I am putting an isomax based hat channel system in for the ceiling. The left, front, right walls are block so I do not have any concerns with sound escaping to other adjoining rooms on the same level. Behind the listening position is an open space and a guest bedroom (also bordered by block walls).
I'm using acoustic putty for the small led lights were putting in the ceiling for lighting, but that leaves me with the in-ceiling speakers and the crux of my post.
Has has anyone ever installed a Triad speaker in a similar ceiling installation? I'm mostly concerned with the opening I would be creating in the ceiling even though the hole would be filled with a speaker. I know I must not bridge the ceiling and joists, it looks like the speakers mount to the joists in both new build and retro. I've seen websites that talk about custom built backer boxes that do not touch the joists or subfloor, I'm just wondering if the speaker's baffling is adequate and how to best mount them.
I'm also curious if anyone has installed the baffled Triad in-ceiling speakers and experienced how much sound is radiates out the back to the above floor?
I've done a fair amount of research but am having a difficult time finding this exact scenario. General concepts I've come across range from "any hole will completely negate all the work you did" to "even with can lights the sound was still significantly muted".
I have a similar scenario with the theater in the basement but kids rooms and living spaces surround it. It's a dedicated theater, so it's not open to any living spaces like yours, but still fairly similar.
I just went with the typical double drywall green glue mounted on sound clips and hat channels. You're never going to get complete isolation, but I can listen to a movie pretty loud without disturbing anyone. Directly above and beside the room, you can hear it only if you turn it up pretty loud. And even then it's pretty muted. The rest of the home you can't hear it, and loud bass notes sound like distant thunder. Decoupling the drywall with clips / channels will help a lot with the lower bass notes which is what you're going to be disturbing others with anyway.
Triad does a good job of sealing and bracing their enclosures, so you won't get any sound leakage from the actual enclosure. Mine are mounted in the wall that is directly adjacent my kids room and it's pretty good.
As long as you're installing the drywall and clips and channels correctly, you'll get some pretty good isolation. If you're installing canned lights, make sure you either opt out, or put sound proofed backer boxes behind them or you'll get major sound leakage into the living area above. I learned this the hard way. Putty those electrical junctions and switches, it seems overkill but actually makes a difference. And it's much easier to do now than down the road when you realize you should have done it.
Also, you stated that the room was partly surrounded by concrete (as is mine). I'm not 100% sure of the layout so I could be imagining this wrong....but If it fits in the budget, I would decouple the drywall / framing from the concrete if it's in the budget. Vibrations will travel up that concrete just the same so decouple it just like you would any other framed wall. I learned this the hard way as well - thinking that somehow a poured concrete wall means sound proofed - which it doesn't. Vibrations = sound, and concrete can carry those vibrations just the same.
The main idea behind sound proofing (especially the lower bass notes) is through decoupling - so as long as you keep that overall theme while planning the room you'll be good. Concrete is no exception.
If your doing it correctly, watching a sit-com at night with your kid sleeping in an adjacent room is completely do-able. My wife and I can watch a regular movie (no big action movies) or comedies fairly loud, and I'll walk into my kids room which is adjacent to the theater and directly behind the main LCR's.... and can barely hear it if at all. Cranking up Mad Max or Mission Impossible to reference levels without disturbing the room next door is another thing altogether - so as long as your expectations aren't unrealistic you'll be golden.