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HT Planning Stage

post #1 of 23
10/22/12 at 4:36am
Thread Starter 
Hello everyone,

I'm in the planning stage right now for my HT. I'm finishing the basement, so I have a fresh open space to work with, with 9' ceilings. After working with the family on the overall design of the basement, I came to the final inner dimensions of 12' x 17.' I would like bigger, but this is absolutely the best I can do. Gotta meet the needs of all family members.

The outer dimensions are 13' x 18' because, after extensive research, I've decided to build a room within a room. I want the best possible sound proofing, and I've read that the best design is to completely decouple HT room.

Here's the plan so far. I will use resilient channel for the ceiling, 5/8" drywall and possibly a second layer of 1/2" drywall with green glue. There will be 4 recessed ceiling lights, where I plan on building backer boxes. I will be covering all pipes and HVAC duct with a sound dampening material, as well as a muffler for the HVAC.

There are a couple of questions that I have that are gnawing at me as I try to gather the numerous facts and tips from the web.

1. I've read that it's best to avoid in-wall speakers when soundproofing a room. I wouldn't mind that, except that I would not have space in back of my last row of seating. But I don't think in-wall would be a problem for the rear speakers in my case if I build a backer box, since the wall will be decoupled. Any thoughts? Can in-wall speakers provide robust sound for a HT?

2. I can't find any good recommendations for how much space between both walls is recommended. Just "as much as possible." I realize that the more the better, but since the room size is constrained, I don't want to space them more than 4 inches apart. Any suggestions as to what the minimum spacing might be without it being a pointless endeavor?

My first step in this process is to study everything I can about sound proofing. Once I'm comfortable with the master plan, I'll start consolidating all of my info on screens, projectors and receivers. This site is such a great source!

Thanks in advance!
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post #2 of 23
10/22/12 at 4:53am
not resilient channel, use isolation clips and Hat channel. big difference.
Yes, backer boxes for rears, consider the Triad brand for robust sound.
Once inch between framing, anything else is gravy but with an interior at 12 ft I'd go as small as possible.
Read the articles at Soundproofingcompany.com
Two layers of 5/8 fire code Drywall, skip the 1/2 don't get the new light weight stuff.
Edited by BIGmouthinDC - 10/22/12 at 4:59am
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post #3 of 23
10/22/12 at 5:00am
A couple of considerations:

-- Any sound isolation effort is only as good as its weakest link. That being said, there is no point doing a "room within a room" for the walls, if the ceiling is not also completely stand alone from the floor joists. By the same token, your weakest links will be your backer boxes (unless seriously robust) for recessed lighting and the proposed in-wall speakers. You may be better off (and have more interior space) using clips/channel. Here's another weak link ... entry door. Is your budget ready for two 350 lb. $3000 doors?
-- What have you considered for HVAC? That's pretty much a weak link to your sound isolation efforts as well. In a tight, well insulated small room, over stuffed with people, you'll be running the A/C and fresh air exchangers in the dead of a very cold winter.
-- Define exactly what you want to achieve with your sound isolaton efforts...unless we know your wishes/expectations we cannot reasonably tell you if your grand plan/mad scheme will meet your expectations.
-- If your seats are that close to the back wall, don't be going to any extremes to accommodate good sound in those seats ... ain't going to happen.
-- Green Glue works best where the two layers are of the same material ... ie, two layers of 5/8", not 5/8" and 1/2".
-- Distance between the walls ... see the first point above.
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post #4 of 23
10/22/12 at 5:20am
You would benefit from posting pictures and sketches of your plans here for review and comment. So many guys show up for help after it is too late to fix a critical error, like door placement. You need to be aware that a 12x18 room is tight. You could skip the double wall framing and do clips and channel on the wall and ceiling, do the double layers of 5/8 with green glue and be pretty happy and gain some precious inches. In this approach I would attach the walls to the ceiling joists with IB3 clips. Knowing what is in adjacent rooms and the nature of your sound proofing needs would help.
Edited by BIGmouthinDC - 10/22/12 at 5:27am
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post #5 of 23
10/22/12 at 9:31am
Thread Starter 
Thanks for the quick responses! I've actually read some good info at soundproofingcompany.com during research these past couple of months. It's good to hear someone support their information!



This HT will serve a few purposes, movie viewing being a smaller fraction, but not less important than the others. We need a quiet room. With 3 kids and all of their friends, there is no place to go to get peace and quiet once in a while. I also want the room to be a place where the kids can bring in musical instruments. My oldest has already shown interest in the trumpet and drums. It will also be a room where I hook up my turntable, close the door, poor a glass of whiskey and listen to what I want. The HT will be used for the kids once in a while (there are only so many kids movies that they like), but mainly for my wife and I and a couple of friends once in a while. I'm a casual gamer. I play at most 2 hours per week, if even that. I might hook up a video game system down there, but it will be off limits from the kids.

From the picture, on one side there will be an exercise room and on the other a general game/entertainment room. What's not shown in the picture is that there is an office and guest bedroom further away. It's not extremely important to go crazy reducing the sound perceived in the adjacent basement rooms. I can deal with some muffled base in that area. The main concern though is that the HT will be underneath a bedroom on the upper floor. When we built the house, we had a wing added for my aging parents. Ideally, I would like to keep as much sound as possible from traveling up under their bedroom. I personally would prefer to have the HT room on the other side of the house, but my home is not a dictatorship (darn), and everyone's use for the basement was voted on. The other rooms are in their place for specific reasons and cannot be changed.

If I scratch the double room idea, I would have a 13'x18' space. That would be ideal. I would probably have enough room in the back where I wouldn't need rear in-wall speakers.

As far as a door is concerned, for now I was just going to buy a solid door. I've read that an MDF fill works well in terms of density. I've also read about the expensive doors designed for soundproofing. It's just not in my budget, and will probably be overkill for my needs.
Edited by nickcin - 10/22/12 at 9:42am
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post #6 of 23
10/22/12 at 9:36am
You can count on moving the entry door. smile.gif

Since a sound isolation door is out of the question, the double wall method is not appropriate since the door would defeat whatever you'd gain by the room with in a room construct.
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post #7 of 23
10/22/12 at 11:17am
While certainly not as effective as one of Dennis's soundproofed doors, you can increase the isolation by adding a layer or two of MDF with Green Glue to your solid core door. This provides more mass and some damping. Keep in mind that the heavier door will require either more hinges or stronger ones and screws that are long enough to pass through the jamb and into the wall framing.

This is what I did and I have been pleased. It was a very cost effective way to get decent results.
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post #8 of 23
10/22/12 at 1:26pm
I'm actually planning out a room very close to the same size, probably 17'x12.5'. It'll be a while before my wife lets me start building, so I'll be interested to watch your progress.
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post #9 of 23
10/23/12 at 3:59am
Thread Starter 
Quote:
Originally Posted by aaustin View Post

While certainly not as effective as one of Dennis's soundproofed doors, you can increase the isolation by adding a layer or two of MDF with Green Glue to your solid core door. This provides more mass and some damping. Keep in mind that the heavier door will require either more hinges or stronger ones and screws that are long enough to pass through the jamb and into the wall framing.
This is what I did and I have been pleased. It was a very cost effective way to get decent results.
That's a good idea. I've seen suggestions for using "quiet door" kits also. You installed the MDF on the HT side of the door only, right? Can you post a picture? I'd like to see how it would look, especially around the edges. I'm assuming that it is a flat door (no paneling)?
Quote:
Originally Posted by trancemitr View Post

I'm actually planning out a room very close to the same size, probably 17'x12.5'. It'll be a while before my wife lets me start building, so I'll be interested to watch your progress.
I'll definitely keep this thread alive with updates. It will be a while though. I'm still getting HVAC quotes. I've got about 5 local Contactors bidding. I think that the majority of the basement will be finished before I get a chance to finish the HT room. Mainly because even though I'm contracting everything else out, this is a pet project that I want to do myself and take my time. It doesn't help that I work 11-12 hour days and have that my kids are too young to swing a hammer smile.gif
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post #10 of 23
10/23/12 at 5:12am
Quote:
Originally Posted by nickcin View Post

I'll definitely keep this thread alive with updates. It will be a while though. I'm still getting HVAC quotes. I've got about 5 local Contactors bidding. I think that the majority of the basement will be finished before I get a chance to finish the HT room. Mainly because even though I'm contracting everything else out, this is a pet project that I want to do myself and take my time. It doesn't help that I work 11-12 hour days and have that my kids are too young to swing a hammer smile.gif
I know what you mean by "pet project." If I had the skills I'd be all over doing the construction myself. I can build speakers, but I just wouldn't feel comfortable with most everything else. I'm sure it will be a labor of love for you. smile.gif
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post #11 of 23
10/23/12 at 5:30am
Since you are getting HVAC quotes if you intend to fill your theater with people and close the door it will get hot on the coldest days we have here. Make sure they provide sufficient air exchanges per hour for this room, that there is a dedicated return in the theater, and that he materials used help isolate the sound from the rest of the house. Be sure you have a plan on how to cool the room when the rest of the house is calling for heat.
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post #12 of 23
10/23/12 at 8:29am
Quote:
Originally Posted by nickcin View Post

That's a good idea. I've seen suggestions for using "quiet door" kits also. You installed the MDF on the HT side of the door only, right? Can you post a picture? I'd like to see how it would look, especially around the edges. I'm assuming that it is a flat door (no paneling)?

Yes, I installed the MDF only on the theater side. I simply screwed it to the door and then moved the door stops back 1/2" so that it still closes flush with the other side. It looks just like a regular door, albeit thicker.

Here's some pictures for you.





And here is the only picture that I could find of it installed (though the rest of the room is now complete around it. biggrin.gif)

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post #13 of 23
10/28/12 at 12:33pm
Thread Starter 
Thanks aaustin. I followed the link to your project and have been learning a lot.

The basement has its own trunc line for its own zone. I was thinking of using a muffler for the branch that comes off the trunc for the HT room. I was going to build a soffit in the rear of the room, lengthwise up under the seating. This would give me a dead vent for air exchange without taking floor space from the HT room or outside room. My ceilings are high enough and the back of the room will be for seating anyway.
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post #14 of 23
10/28/12 at 3:53pm
I am glad that my thread is serving as a source of information for you. That is one of the reasons why I started it.

Rather than a dead vent in the back of the room, you should consider a soffit muffler. You would run flex duct the length of the soffit and then fill the space around it with fiberglass insulation. It serves the same purpose as a dead vent (and I think that this is what you were planning anyways), but is designed as a long and skinny muffler rather than one large box.

Keep in mind that you'll need a return for this room too that will require the same type of treatment.
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post #15 of 23
11/8/12 at 4:39pm
Thread Starter 
Quote:
Originally Posted by aaustin View Post

I am glad that my thread is serving as a source of information for you. That is one of the reasons why I started it.
Rather than a dead vent in the back of the room, you should consider a soffit muffler. You would run flex duct the length of the soffit and then fill the space around it with fiberglass insulation. It serves the same purpose as a dead vent (and I think that this is what you were planning anyways), but is designed as a long and skinny muffler rather than one large box.
Keep in mind that you'll need a return for this room too that will require the same type of treatment.
Hurricane Sandy tied me up for over a week. Time to get back into this!

Yeah, I guess the soffit muffler is what I had in mind. I have the terminology mixed up smile.gif

Regarding your framing, did you do the staggered stud construction for all walls? A couple of the walls don't seem to have this when looking at your pictures. I can't tell.

If on all walls, did you use whisper clips on the HT side only, or both sets of studs? I'm trying to decide if I should use the whisper clips on the next room that shares a wall with the HT. I already planned on using a second layer of drywall and green glue on both sides. I guess the staggered studs would provide further isolation.

I got my quotes for the hvac. Looks like its going to run around $3,000. Going to include a return in the HT room. They might be able to start next week. I'd like to get the framers in soon afterwards. So I need to make the right decisions soon smile.gif. This is nerve-racking! I wish I had a month off from work!
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post #16 of 23
11/8/12 at 4:45pm
You want the walls decoupled, and this can be accomplished by staggering the studs, building a double stud wall, or using clip&channel. Pick one. Clips go on one side only.
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post #17 of 23
11/8/12 at 5:12pm
I only used clips and channel on the ceiling. Two of my other walls are staggered stud, one is a double stud wall (I needed the extra depth to conceal a support post), and the last one is a single stud wall built about one inch away from the concrete foundation.

If I had a larger room and didn't have to worry about saving every inch I would have done double stud walls instead of the staggered stud for the improved decoupling.
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post #18 of 23
11/9/12 at 9:57am
Thread Starter 
Quote:
Originally Posted by aaustin View Post

I only used clips and channel on the ceiling. Two of my other walls are staggered stud, one is a double stud wall (I needed the extra depth to conceal a support post), and the last one is a single stud wall built about one inch away from the concrete foundation.
If I had a larger room and didn't have to worry about saving every inch I would have done double stud walls instead of the staggered stud for the improved decoupling.

Here is a picture of the staggered stud design from soundproofingcompany.com:



It shows a 2x4 ripped to a 1x2 and attached with acoustic sealant and nails in order to gain an extra inch for the staggered wall. But there are still 3" of stud on the main wall frame, plus the nails serve as a sound channel into the main wall frame. Looking at your pictures, it looks like you used a 2x6 instead of a separate decoupling strip. How did you decouple the top of your wall frame from the ceiling joists. I can't tell from your pictures if you left a gap or if they are nailed. Also, for your double wall, was it basically a second wall separated from the main wall?

I'm thinking that going with hat channel and whisper clips for the walls and ceiling might be the better option for my situation. It just seems like it would provide better isolation. The extra cost would be offset by the savings in labor, I would think. Do you feel that the steps you took provided you with adequate sound isolation? Anything that you wish you would have done differently in that regard?
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post #19 of 23
11/9/12 at 10:32am
staggered stud = Good
Clip&channel = Better
Double stud = Best
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post #20 of 23
11/9/12 at 10:45am
I believe that the method outlined on The Soundproofing Company website that you describe is for converting an existing standard stud wall to staggered stud. Since I was building these walls from scratch, it was easier to just use a 2x6 top and bottom plate.

None of my walls are in direct contact with the ceiling joists. I used IB-3 brackets to attach the tops.



I have been extremely happy with the soundproofing. The only thing I can hear in the room are some footsteps, but that is to be expected since the room above the theater has hardwood floors and impact noises are so hard to stop. When a movie is playing though, this is rarely noticeable. The only thing that escapes the theater are deep rumbles from the sub during heavy action movies and occasional other noises when I have it up REALLY loud (this was only when testing how hard I could push it). There is a bedroom off of the same hallway in the theater and someone can sleep in there comfortably while a movie is playing at near reference levels.

If I was to do it again and I had more space and money I would have done double stud walls all around instead of the staggered stud. I also would have put a lot more thought into putting drywall and Green Glue between the joists to help tame some of the impact noise.
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post #21 of 23
11/11/12 at 3:11pm
Thread Starter 
Thanks guys. I've decided to go with clips and hat channel to isolate the walls and ceiling.

I'm planning on a 120" screen. The projector I want requires 16' distance for this size screen (based on a projector throw calculator I used). My thought was to install a sheet of plywood towards the rear of the HT room so that I have some flexibility mounting the projector. I would install the second layer of drywall with green glue over the plywood. Is using 2 types of material recommended? I don't see any other way, because I doubt that the hat channel would be strong enough to support a projector mounting bracket.
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post #22 of 23
11/11/12 at 3:16pm
There is no problem using a first layer of plywood or OSB. Many people actually do OSB for their entire first layer to allow for more flexible mounting options all around the room.
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post #23 of 23
11/29/12 at 9:53am
Thread Starter 
Update:
The HVAC is installed and waiting for the framing. The framer is coming next week, and I'll be taking off from work to direct him on the HT room. I have the IB-3 brackets ready for him for the wall isolation from the ceiling joists.

Question:
I asked the HVAC guy to install 1 supply and 1 return and to leave a lot for me to work around a soffit. My wife and father-in-law were home when he installed it. He said that he felt we may need 2 supplies. The room will get warm with 7 people and a projector, but do I really need 2 supplies? It's in a basement, so I have the underground cooling working for me. He's coming back and said that he can remove it if I want.
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