Soundproofing a room

[RabidRabbit]

Hey guys.

I am just about done framing my new room in the basement I am turning into a theatre. I want to sound proof this as best I can, within reason. I was planning on using either Roxul Safe and Sound or O/C Pink Quietzone (which I hear is the same as the R-13 insulation) in the walls and ceiling (main level floor joists), paired with doubled 5/8" drywall on the ceiling and the one wall that leads to the rest of the basement, the other three walls are outside walls which were framed/insulated/vapour barriered by the builder.

Is there anything else I should be doing? I have heard about Green Glue but it seems very expensive and probably not worth it for me.

Has anyone use plywood as the first layer against the joists, and then drywalled over that? It seems to me this may block sound better than two layers of drywall but I don't know if there are any long term effects/fire hazards etc of using plywood.

I don't need the room totally soundproof, but obviously the quieter the better. I don't know that much I do is going to stop the bass during action movies.

[Matrix_dot_ca]

i am doing mine next month. I'll be using Quietrock as drywall and roxul as insulation. Using the room in the basement as theatre room as well.

[Neil]

Hey guys.

I am just about done framing my new room in the basement I am turning into a theatre. I want to sound proof this as best I can, within reason. I was planning on using either Roxul Safe and Sound or O/C Pink Quietzone (which I hear is the same as the R-13 insulation) in the walls and ceiling (main level floor joists), paired with doubled 5/8" drywall on the ceiling and the one wall that leads to the rest of the basement, the other three walls are outside walls which were framed/insulated/vapour barriered by the builder.

Is there anything else I should be doing? I have heard about Green Glue but it seems very expensive and probably not worth it for me.

Has anyone use plywood as the first layer against the joists, and then drywalled over that? It seems to me this may block sound better than two layers of drywall but I don't know if there are any long term effects/fire hazards etc of using plywood.

I don't need the room totally soundproof, but obviously the quieter the better. I don't know that much I do is going to stop the bass during action movies.

It's good that you realize you'll only be quieting, not sound proofing.

Some things to consider doing that are still possible...

- stagger the studs
- use resilient channel and other isolation tricks
- use gaskets along wood edges
- use the roxul
- seal any gaps
- address any situations where there will be a hole (wrap sound deadening material around the back of electric junction boxes for instance)

Are you saying the ceiling is done or not done? It's better if it's not because that will be a major sound chamber if it doesn't have the benefits mentioned above.

Imagine that sound is like water or air, and think of all the ways it can flow. Think about your exterior walls for example. Remember that even a small sound hitting a certain shaped space can be magnified like a drum.

So you might think you can ignore exterior walls for example. But are there openings and penetrations that will take sound hitting those walls and leak it into the ceiling or upstairs? Do what you can to prevent this, but make sure you are obeying fire safety building measures too.

I recently saw a foam insulation product that claimed sound benefits, but haven't used or researched it yet.

I don't know about using plywood. It sounds unconventional and more expensive than just using 2 layers of drywall.

Use room finishes that will help, not hinder your objective. Use soft carpet, absorbent furniture, drapes over walls and windows, etc. Avoid sonically reflective surfaces like glass, granite, hardwood.

[chadjustine]

Along with everything else that has been said (all good advice), check out: avsforum.com.

A sh*it ton of information there.

[RabidRabbit]

I have been on AVS for years and years, but there sometimes is just too much information... Finding an answer you need in a 200 page thread can be a chore.

The ceiling is not finished right now. I am going to be putting the insulation up there before drywalling with double 5/8" drywall. My problem with the drywall is 4' x 8' x 1/2" is like $10/sheet, whereas the same thing in 5/8" is $22 a sheet, seems like a total ripoff. Plywood is $17 a sheet I believe. Would going to doubled up 1/2" as opposed to doubled up 5/8" really cost me a lot in sound dampening? I just don't know that paying more than double for the 5/8" to stop 3 db or something is worth it. I can even use acoustical sealant between the 1/2" layers and it's still way cheaper. Heck, I can triple 1/2" it and be cheaper than double 5/8", and thicker.

[ken0042]

I too went for a cheap solution and used Roxul safe & sound in the ceiling, then 5/8 drywall. Now the only way the sound is travelling is from the stairway and the heat vents.

My cousin is staying down there with his screaming 3 year old kid, and I can barely hear them. So that was good enough for me.

[RabidRabbit]

I too went for a cheap solution and used Roxul safe & sound in the ceiling, then 5/8 drywall. Now the only way the sound is travelling is from the stairway and the heat vents.

My cousin is staying down there with his screaming 3 year old kid, and I can barely hear them. So that was good enough for me.

Is this single 5/8" ?

[sods]

It may be related to demand... I believe 5/8" is minimum for firecode if you put in multiple apartments (ie duplex). Not sure if it is building code for a normal SFH though. just my guess, however far off it may be

[RabidRabbit]

It may be related to demand... I believe 5/8" is minimum for firecode if you put in multiple apartments (ie duplex). Not sure if it is building code for a normal SFH though. just my guess, however far off it may be

You are probably right, I do know at the HD here they have at least 20 times as much 1/2" in stock as they do 5/8".

I think I am just going to double up on the 1/2". It will be less than half the price of the single 5/8" (have to buy double screws, no biggie) and I imagine will provide better sound retention.

[mbg]

For ****'s sake...

[mason]

I lived on AVS forum for months while I was finishing my basement & Home Theatre. The Green Glue thing drove me crazy, because if anybody questioned its utility they were spiked down faster than you could imagine. Personally I couldn't justify the cost and hassle of using it.
I did a 6" exterior wall, staggered studs, Roxul S&S, 2 layers 1/2 drywall all around Dri-core subfloor. No resilent channels, No GG. Mainfloor directly above, you can hear dialog (but not clearly), 2nd floor nothing. Bass travels to main floor, but not on 2nd floor.

If I was to do it again, the only thing I'd change is to use the Quietrock instead of reg drywall (maybe give the resilent channels a go).

[RabidRabbit]

For ****'s sake...

huh?

[RabidRabbit]

I lived on AVS forum for months while I was finishing my basement & Home Theatre. The Green Glue thing drove me crazy, because if anybody questioned its utility they were spiked down faster than you could imagine. Personally I couldn't justify the cost and hassle of using it.
I did a 6" exterior wall, staggered studs, Roxul S&S, 2 layers 1/2 drywall all around Dri-core subfloor. No resilent channels, No GG. Mainfloor directly above, you can hear dialog (but not clearly), 2nd floor nothing. Bass travels to main floor, but not on 2nd floor.

If I was to do it again, the only thing I'd change is to use the Quietrock instead of reg drywall (maybe give the resilent channels a go).

I will probably use the Dri-core as well (although the price has recently jumped so may use Delta-FL) and definately going with carpet.

I don't really want to use the resilient channel because a) I am afraid it will sag over time with so much drywall on it and b) it will be a PITA to install the pot lights and other things in the ceiling.

I agree about the green glue, I don't doubt it works, but $16 a tube? I would have to spend about $400 on the stuff. I'd rather wing it with acoustical sealant for $3 a tube, I'm sure it doesn't work as well but it has to do something, and it's cheap. The guys on AVS are mostly pretty hardcore and want the best solution for everything... Something that just falls short, at any cost savings, is not good enough. Several of the guys on that forum have well into six figure theatres. Heck, some of them have that in the speakers alone.

[chadjustine]

For ****'s sake...

I thought the same thing after reading your intelligent post ...

[RabidRabbit]

On another topic, this room is about 20' x 13' x 7.5'. I bought four par20 pot lights last night, and a couple sconces. I think I am going to return the sconces though and get two more pot lights. Will six 4" pot lights @ 50w each be enough to light the room? I don't need it very bright, obviously... But I'd rather have it too bright than not enough as they'll be on a dimmer.