Room building 101 questions

[Rowdy S13]

We are starting to get down to GO time on wiring up my home theater/house. As some of you already know I recently bought my first house, and am VERY excited to have a dedicated space for a surround sound set up. It wont be a true dedicated Home Theater, but that is the main focus of it. I have already made a couple threads going over some of the broader things like layout, wiring, etc. What I am still not very sure on is acoustics.

My main question right now is, should I be doing anything to the room right now? Should I open the walls and add in insulation? Should I double up drywall with green glue? Should I do both of these things? Should I do something completely different? Eventually I will add things like traps, and panels, but those will come later.

The room is in the basement, but only about half underground. Two of the walls (where the screen will be, and the left side) are outside walls. The right side is an inside wall that has a bedroom/office, and a bathroom/utility room on the other side. The back wall has the opening for the stairs, and is also partially underground. So the bulk of the room (2.5 or 3 walls) are insulated to some degree. I say 2.5 because the above ground part of the back wall is the upstairs living room, so probably not insulated.

I dont mind ripping out drywall and putting up new especially because I will be making holes for wiring anyway. I am just not sure if it is really worth all the effort/money. ANY help that you guys could give me is greatly appreciated. If you have any question for me ask away!



Thank you,
Sean

 

[TheWarrior]

If you are willing to do it, go for it! But remember when running wire: think about what your future needs might be, not just now. If you're going to put in the effort (and you shouldn't need to completely dismantle your existing drywall) then go all the way so you are future proof!

Doubling drywall with or w/o green glue is highly recommended as an economical way to keep sound contained. You will want to insulate your ceiling, and definitely do double drywall there. If there are any means to decouple your upstairs floor from that basement ceiling, that is also advised for the day when you buy extra subwoofers.

Enjoy!

 

[Rowdy S13]

Yeah the running wire part is easy for me (and my electrician best friend). I have plans for running wire to 4 locations in the ceiling, spare drops at the front and rear of the room (height channel, or Bi-Amp), drops in the garage for Zone X, drops in the back of the house for Zone X, and a handful of other ideas rolling around

I am not too worried about completely isolating the room since its just the wife and I. I am more concerned with making the room better overall for acoustics. It seems like the best ratio of work/money vs return would be a second layer of drywall with green glue. I think I would probably rather hang a second layer using 2 tubes per sheet than spend the time/money on insulation and re-drywalling (with also adding a second layer). Unless there is a very strong reason that insulation is the way to go, I will probably skip it.

Thoughts, ideas, suggestions?


Thanks,
Sean

 

[Rowdy S13]

Moving on, anybody have any suggestions for large amounts of wire? I probably need 1000-1500 feet of 12ga speaker wire to do the whole house. Monoprice isn't too bad, but just wondering if anyone knows of anything else.

Thanks,
Sean

 

[Rowdy S13]

Time for an update, and a rehash At this point the wire is all run in the main room. It is just roughed in for now until I have speakers in my hands so we can be 100% sure where and how we are terminating. In running the wire though, we found that the ceiling drywall was hung like poop. Its cheap flexible drywall that was glued and nailed which means it is VERY wavy. So for sure the ceiling at least is all coming down. I have verified that the front wall, and left wall are insulated (being outside walls), and that the rear wall is half insulated (being half underground, and half inside wall). The right side wall has no insulation anywhere.

Now for the questions. While everything is open in the ceiling what should I do? Should I add insulation, and if so what kind? I see that it can get very expensive very fast so I could really use some guidance on this. What about that right side wall? We didn't have to do anything to that wall at all, so if I insulate it I would need to open it up to do so. Also, because of the way the house is laid out, adding a second layer of drywall is more complicated than it seems. I am still planning on a second layer of 5/8" drywall (any guidance on types is helpful) with 2 tubes of green glue per 4' X 8' sheet on the other three walls and ceiling. Doing anything on that right side is a pain in the ass, so would it be very detrimental to the sound to leave it as is?

This is not a dedicated room, and I am not worried about sound in other parts of the house. I am just trying to make it sound as good as possible in the room without spending $10,000. Drywall, insulation, and Green Glue seem to be relatively inexpensive depending on the specifics of each and possibly offer the most gain for the money/work involved. But even within that small group of items there are a TON of different types to choose from. I know nothing about any of this, so whatever help you guys can give me is GREATLY appreciated!



Thank you,
Sean

 

[Gordonj]

Sean, sounds like a great start on your new home and room, congrats!

The drywall question - insulation in a wall, in general, adds 1 to 2 dB of isolation to the wall system and helps dampen the wall system. So, I would insulate the ceiling system just to help isolate the room form the space above. The 5/8" gyp board is a good start and is better then 1/2" because it is thicker. The thicker the insulation the better or acoustic batting is better. Remeber all the insulation is doing is absorbing the noise between the two systems.

Since you are not worried about isolation to the rest of the house then I would not worry about the other walls. The ceiling system is always a wise choice so that it controls some of the noise going up. At this point adding drywall to the wall systems, since you are not concerned about isolation as much, will lower the resonance of each of the wall system so you start "tuning" the room some. Will that tuning have a big impact? Not sure. And frankly not sure if I would worry about it.

Have a fun time with it!

Gordon

 

[Alex2507]

Don't remove any drywall that you don't have to on the ceiling. More in a minute.

 

[Alex2507]

On the ceiling I would only cut out what I had to keeping in mind sheet dimensions for an easy repair job. For example I would not cut a 25" or 17" or 13" channel. 24" and 16" and 12" dimensions allow for free pieces without extra cuts or extra sheets.

I would insulate what I could reach and then patch those holes and rescrew the rest of the ceiling @ 12" OC. 1/2" resilient channel would go on that @ 16" OC and then a layer of 5/8" DW. The RC channel can be shimmed to get rid of the dips. It's okay to attach the stick of RC channel with a screw @ 32" OC to skip high spots. Check out You Tube if you need tutorials.

I figure that saves the work of demo and disposal while saving you the cost and delivery of material. Use what you have. Same goes for the walls. Cut and patch as needed. Stay away from the baseboard, cornerbeads and inside angles if you can but rescew everything. Rattling sheets ... rattle. Additional layers call for jamb extensions and the reworking of base boards and never mind if you have baseboard heaters.

Since you don't care about sound transmission, don't bother attenuating it. Stop the walls from adding to your sound by screwing them down. That's cost effective.

 

[Rowdy S13]

So the general idea would be to get insulation in from the opening I have already. Try and get as much in as possible, but don't worry about 100% coverage. Screw down the existing drywall on 12" on center spacing along all of the joist. Probably do the same on the walls just to be safe? Then also on the ceiling attach the 1/2" resilient channel 16" on center (attach them to the joist?) shimmed as needed to make a flat level surface, and then add a second layer of 5/8" drywall.

That sounds not bad, and more cost effective probably. I don't know anything about the resilient channel product, but I can research Also, are we thinking just R13 insulation? I know nothing about this stuff, so sorry for the dumb questions guys.


Thanks,
Sean

 

[Rowdy S13]

OK, after some discussion with my buddy who is helping me with this project we took this information into consideration and came up with a plan. The plan is still to bring down the whole ceiling first. The reason for this (besides it being pretty poorly installed) is to give us better access for electrical work, and insulating. This can all be done without taking down the ceiling, but with as much patching as will be needed, and the current condition of the ceiling it seems like it is worth the work. So the ceiling is coming down, we will run the electrical, get everything as nice as possible, put up insulation, and make sure nothing in the ceiling can rattle. Then I will install the Resilient Channel (I see that you want it to be running across the joist, not with them), and hang a single layer of 5/8" drywall.

I will probably also look at some options for different duct work for the two registers in that room to help with HVAC noise. I may also move the one register to get it further away from the screen so it doesn't end up blowing it around. I am also going to replace the recessed lighting that is in the room, and rewire it for better lighting control. Basically there is a handful of things I am going to change/fix while I have the ceiling open. I am not trying to make a perfect room, but this work should help the sound and I will feel better knowing that it was all done right. I will be sure to update here as the work progresses.



Thanks,
Sean

 

[Alex2507]

The R value will be associated with a particular thickness. To reduce transmission as effectively as possible they say you need to fill the void completely. So if it's too thick and you compress it it's not a problem but throwing 3-1/2" batts into a 10" gap is just getting itchy for nothing.

I missed your question up until just now and I'm a little pinched for time so I gottsta go.

 

[Alex2507]

btw, your existing ceiling should be on furring strips that run across the joists, right?

 

[Rowdy S13]

Well that is good to know! So I need to get something like R30 to fill the 12" of my floor joist? Is that going to help improve the sound all that much?

Currently the ceiling is NOT on any furring strips of any kind. When I redo the drywall I will essentially use the resilient channel as furring strips.

I have two goals here, the first is to make it look nice when its all closed up. Which really means fixing the wavyness. Second to that is improving the overall sound quality within the room. It is NOT a dedicated theater room, so I am not going hardcore with isolation and perfect acoustics, but if I can make some improvements while its open without breaking the bank then I will. The resilient channel seems to be the best bang for the buck thing I can do while also repairing the ceiling and doing all of the wiring. I know pretty much nothing about this side of things though, so please teach me!


Thank you,
Sean