Axiom Home Page Forums General Discussion Home Theater HT in-progress

Yes they have a very good coating on the out side and there should be good drainage around the footing … but if you pour enough water down the foundation walls fast enough it will still find it’s way though.

Ah, rabbit hole.
got it

Well, it's 3 months later and I haven't moved much ... the guy that's helping me needed to take some time and we have just started up again. Finally putting back up the channel



In the mean time a few things changed. I've decided to use OSB only on the ceiling (to hang speakers) and on the electric wall (a 3' wide wall section which is inside a 11" alcove turned cabinet). Between the OSB and the wall board sandwich I'm putting some squishy floor underlay (thanks Trevor) which will hopefully allow the sandwich to vibrate a bit (who knows if it will work). The other walls will just be two layers 5/8s wallboard with green glue. I'm not 100% sure if I'm gaining or loosing by getting rid of the OSB behind the walls but at least I know what to expect performance wise.

I also doubled up most of the in-wall wiring that the electrician put in. It was too small a gauge for most of the runs and they did some creative wiring ... one 30' run had over 50' of wire in it (my guess is they ran it to the wrong place and then just kept going). I would have pulled some of it but most of it was unmovable being in the spray foam insulation. Anyway now all speaker run have a damping factor over 100 ...

Finally a fire alarm wire was snaked and attached to the halls fire alarm and all the MLV was hung ...

I think the approach i'm going to take in ceiling is safe n sound against the subfloor, then normal insulation (since we already have it we may as well use it), sound isolation clips with furring channel, osb, then 5/8" drywall with green goo. I'm still doing some research but the biggest obstacle is trying to prevent the lower frequencies from making it upstairs.

Think this is what your saying (from subfloor moving down to HT ceiling):



where i'm doing:



Think the OSB question was about stiffness. 1/2" OSB has some flex and suspect it should work as one side of the green glue sandwich. In my case with 3 layers I'm not sure if it's reducing the effectiveness of the green glue. I'm hoping for some absorption in both the green glue and floor muffler but ...

It's an experiment which, If I get ambitious, I might try to measure.

Think this is what your saying (from subfloor moving down to HT ceiling):



Correct. I wanted to add the osb strictly to have flexibility for mounting speakers or projector while also adding some mass.

Your ceiling will certainly have more mass than mine. Fortunately I don't have to worry about the walls too much but I will probably still add clips and channel along the inside dividing wall and on the outside of the stairwell. It'll all be insulated with safe n sound.

From my understanding you need to decouple the whole room from the studs to be effective. So, I would definitely do the walls.

From my reading, sound will probably find a path upstairs if you don't. Maybe Trevor (or someone in the know) can chime in with their thoughts on that ...

On mounting the projector ... After discussing this with Trevor, it was decided to screw the projector mount to the floor joists and have it stick through the ceiling.



One worry I had was that the ceiling is designed to vibrate. If that transferred to the projector would you see it on the screen? This is probably a non-issue as I could find no mention of it as a problem but ... doing this made me feel better. It's also the way Trevor does it in his installs. 2nd it allows the option of mounting a heavier projector and 3rd a nice way to route cables (the pipe runs to some conduit which goes to the equipment cabinet).

Are you doing in-ceiling speakers for Atmos?

I'm putting M3 on-walls on the ceiling. First go will use FMBs to mount them ... but I may opt to mount them flush later.