Manitou Theater Room

Introducing myself and our project:

My name is Nick and we live in Colorado, near Colorado Springs. We are building a home theater/music listening room in an unfinished area of the lower level of our house. The home is a southwestern contemporary. We are thinking of a western/rustic scheme for the final design, but not too much theater. At this stage I am mostly focused on construction and functionality. I kind of figure that if I take care of the technical aspects properly, that the designer touches will be my wife's area after the main construction aspects are completed.

It is probably important for me to mention here that we are amateurs in the audio/video realm. My wife likes to watch movies and I like to listen to music and read books in a comfortable setting. The current location of the television allows the sound to rise up through an open staircase into the living room - so it is hard to get away from the sound of a movie. Plus the TV we have been watching for so many years seems to be shrinking!! (28 diagonal seemed large when we bought it!)

The basic layout is shown below with the screen centered to the right of the door on the lower wall (the wall with the bathroom on the far side). The current plan is for a 55 TV, but I plan to go ahead and run AC, CAT5 and HDMI to a spot on the ceiling in case we (or a future owner) decide to run a projector.


The master bedroom is directly above the HT and sound transmission is a concern. Since we are in an area of Colorado where we are required to build any non-bearing walls as floating walls we decided to stand the walls on the slab and have the gap for the float at the top. My theory is that this should allow less of the vibration to be transferred to the joists above when compared to hanging the walls from the joists as is often done. We are planning to use double drywall and Green Glue on all the surfaces and to hang the drywall on the ceiling from whisper clips and hat channel.

We have just had our framing inspection and had no issues. I was concerned about fire blocking, but it seems that giving it some thought was enough to figure out what needed to be done. One thing I would change if I were to do the fire blocking again is that I would not use the Great Stuff Fire Block foam, as it seems to me to transfer too much vibration from one surface to another - instead I would stuff the gap with fiberglass insulation. It is acceptable to the inspector and seems to transfer less sound. (This is not a scientific observation, but it seems to be the case when listening to what happens when you tap on a stud that has foam between it and another stud, and then tap on another where fiberglass was used as fire block.) Fiberglass is cheaper and less messy too.

We are building a room within a room and have received a lot of advice from John at SoundProofingCompany.com

For the gap at the top of the floating wall we used a roll of mass loaded vinyl with fiberglass insulation in the middle. We also used deep metal channel to make it easier to stand the wall up into and figured it would give a bit more seal to the floating wall gap area.

We used flex-track for the top and the bottom of the curved wall to keep from having to spend a lot of time and money on building curved top and bottom plates out of plywood. We are pleased with how it has turned out so far.

The photo below shows the top of the walls at the intersection of the straight wall on the left of the layout at the intersection with the curved back wall.


I am now moving into the stage of trying to figure out what I need to pre-wire for and what extra wiring I might want to put into place for future needs. I am also trying to figure out the equipment cabinet questionbuy one vs. build one???

The equipment to be used is partly still to be determined as deals are found. I stumbled upon a set of PSB speakers at a used furniture place and purchased them at the recommendation of a couple acquaintances. (2) PSB Century 400i speakers with stands, (2) PSB Image 4Ts, a PSB Image 8c with a stand and a Definitive Technologies 12 subwoofer.

That's the status at this point. My wife is ready to watch movies as soon as possible, but I have told her that it will be complete when it gets completed and that is the only schedule I can give her at this time.

Any suggestions that may save us some grief will be appreciated!

I hope the photos come through OK. This is my first post to the forum and I tried to do it right!

I have been busy working on the room and as a result, have been remiss on updating this thread.

Since we got the rough framing inspection out of the way, we headed for the electrical and mechanical inspections.

The building department folks required that based on the number of bedrooms in the house (3), we needed to have a supply of outside air and a vent fan that moved at least 60cfm per minute. I thought that this was unnecessary, but figured that I wanted to have the room done with a permit and so I would have to go along with their demands.

Just about as soon as our son and I started working in the space, we found ourselves opening the vents and running the fan! I might see about getting a fan that moves more than the 80cfm fan we got.

(By the way, we were looking at the vent fans at Home Depot and to get one that moved 60cfm was going to be expensive and noisy. We asked for assistance and found that a 4” fan pre-mounted in a short piece of metal duct moved more air and was rated a significantly quieter than the more expensive “bathroom fan” type of product.)

I have routed the ducts through the mechanical room next door to the theater room so that the electrical damper and fan are accessible.

The wiring went pretty smoothly and we went ahead and ran a dedicated 12ga run and an HDMI cable (not right next to each other) to a place on the ceiling where someone in the future might want to put a projector.

We also prewired so that the rear speakers could be mounted high or low.

The rough-in electric and mechanical inspections both found no problems, so we jumped into the insulation step. (Cornstarch rubbed onto any skin that might be affected by the fiberglass seems to reduce irritation!)

Whisper Clips and hat channels were installed.

Today we started the drywall. 5/8” went on the ceiling and we will be adding Green Glue and a ½” layer to it tomorrow. The flat walls will be getting 5/8ths-GG-1/2 and the curved wall which has 2x4 studs on 12” centers will be covered with 2 layers of ¼” with green glue. I know that is nowhere the same mass as 5/8 + 1/2, but because of the curve, the de-coupled wall, fiberglass and the masonry wall behind it, I hope that it will work well enough. Bending that 5/8” drywall would be a problem!

My son (23) asked what the next step after the drywall was to be – I had to say, “I have no idea!” I have been thinking that it would be starting the acoustic treatments, but I have been so busy with the construction to this point that I have not settled on what we should do.

At this point I am still thinking that because of the small size of the room, and the short radius curve of the back wall, I am going to need a lot of absorption in the room.

I expect that we will be using 1” Owens Corning material or the equivalent, but I have not had the time to read enough of the entries on this site to know which is which or what is who!

I also expect to cover the screen wall and the first few feet of the side walls (as far as the doors) with the same material. Then from there to the back walls just the lower part of the walls. The back wall, I expect will be absorption top to bottom, side-to-side.

Suggestions???

That brings us up to the moment…

A couple photos follow showing the changes of late:

A view of the entry door as of this morning:

A view of the same door this evening (shows that we really did do some drywall work today...the side walls are not at right angles to the screen wall, and the back wall is curved, so fitting some of those pieces is complex!):

Aaustin,

Thanks for getting me off the dime and getting this update posted!

We are still working on installing the drywall.

As it has been suggested that we should put more mass on the curved wall than just 2 layers of 1/4" drywall, we have decided to add a 3rd layer to that wall.

Since we will be completing the drywall installation over the next few days, and I don't have excess Green Glue on hand, is there a preferred location for the Green Glue...as in should it go between the first and second layer installed, or between the second and the third? (I am sure that it would be better to have it between each layer, but I don't have that option at this point.)

Here is a photo of the state of progress as of Friday evening:
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Thanks!!

Aaustin,

That is a logical way to look at it. (Therefore it had not occurred to me!) I guess unless one of the scientists on this forum makes an argument to the contrary I will proceed with that method tomorrow when we get back to hanging drywall.

Thanks for the thought.

Now my head is starting to hurt as I try to figure out what to do with acoustic treatments for this unusually shaped room...

Update:

The drywall is hung and the finishing is in process. The drywall guy said that he had never spent as much time hanging drywall in one room as he did here. He said that we had close to 50 sheets in this one room. DD GG with 3 layers on the 22 ft curved wall.

I have spoken to several folks about the acoustic treatment requirements for this room and have gotten some basic advice, but so far I have not gotten anyone to give me a comprehensive acoustical plan for the room (either for free or for $$). So what I am planning at this point, is to come up with some bass traps and some absorbers for the most obvious points, and to experiment after that.

The room has a few places where your own voice comes back to you with such force it is almost painful!

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Aaustin,

The 5/8" drywall is heavy!! Luckily, there were three of us on hand to carry it, to do the ceiling, and to push the 1/4" sheets into the curve. I certainly would not have wanted to take that on solo!

So far I am pleased with the apparent "soundproofness" of the room. I have not had someone make noise inside while I stood outside or the other way around, and I have not installed the door between the mechanical room and the HT, but from what I have seen (heard) so far, I am pleased.

I don't have much at risk with sound leakage (in or out), so I am not worried about the doors I have in place for now.

It is pretty dramatic when one builds something like this...the way the sound changes as the space gets framed in, as the insulation is installed and then as the drywall is in place...a lot of sonic changes.

Hey Kurt,

Wave! I can probably see you from here! We are up above Manitou about 800ft in the lower part of Crystal Park. I can see the western part of Falcon but can not see the beacon at Meadow Lake airport.

Holler when you are over this way sometime if you want to see what the current state of the room is.

I think that curved wall will be a fun aspect of the room when we get things completed, but it will be a challenge.

Right now the acoustics are scary! My wife and I were trying to have a conversation in there last night and had to step out of the room because it is so echo filled that it is hard to understand each other.

She is going to try to pick out paint and carpet concepts so that we can get started on that when the drywall guy is done with the finishing.

It is not going to be real "theater" look, more of a sitting room concept.

Later,
Nick

Bob,

With regard to isolating the floating walls from the ceiling joists, I figured that with the walls resting on the slab instead of hanging from the joists, and with the holes for the spikes being a bit over-sized that there would not be a lot of vibration being transmitted directly into the joists.

We did use a roll of mass loaded vinyl with loose fiberglass inside to reduce sound transmission that way.

This photo shows the end view of the curved wall (using the steel flex-track). The bit of white that can be seen above the roll of vinyl is drywall that we installed first to allow for sealing the top of the wall space for fire-blocking requirements.

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On the top of the straight walls we put up a 2x4 under the joists, attached a length of deep steel track to that, installed the roll of vinyl/fiberglass into the steel track temporarily by screwing through the side of the steel into the vinyl, then stood the wall up under the vinyl and removed the screws.

In the photo below you can see the intersection between a straight wall on the left and the curved wall on the right. The vinyl "sausage" is enclosed above the straight wall in the steel channel. I figured that the steel would make installation and containment of the vinyl easier and might add another encumbrance to any flanking sounds without adding much to the cost.

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I am getting closer, but I have not tested the room for sound transmission yet. It seems to me that there is not much more that could be reasonably done without resting the walls on the floor and then building a completely decoupled ceiling beneath the existing joists. I am sure that the inspectors would accept this, but it would add to the materials and labor investment significantly.

I hope that helps. Let me know if more photos or explanation of what we did might help.

Nick

(Trying again...I put together an update posting and when I went to preview it...I was told that I was not logged in! Maybe I am a slow typist, but that is really frustrating.)

The drywall is completed, textured and painted.


The electrical is complete with the exception of picking and installing light fixtures and a couple things for the electrical final inspection.

The speaker connection wall plates have been ordered...(prices from $3-something to $20+ each!!! I went with the $3-something ones!)

Since I didn't want to use can lights for the reason of sound transmission (or the extra effort to build backer boxes), I found some shallow ceiling boxes that are shallow enough to only penetrate one layer of the two we used on the ceiling. (In the photo you can see a bit of the edge of the box standing proud of the drywall, but we used 1/2" drywall for our second layer, so if you use 5/8" drywall it would be about flush.)

I expect that the type of fixture that we are planning to use will cover this exposed edge and it will not be a factor. After the drywall was finished and the texture applied, I used a 4" hole saw (with the drill bit removed), pulled the Romex through a hole in the back of the hole saw and rotated the saw back and forth by hand. It was very effective and not very much work!

WAF is very high at this point. She is the one who is the movie fan, and I like to build things.

Now trying to find carpeting the is reasonable, the first two choices were very nice - and very expensive!

That the current status.

Bob,

(I forgot to mention that we ran a drill bit up through the hole in the top plate so that the spike would go through the vinyl/fiberglass without compressing it as we drove it into the wood above.)

I would expect that the caulk would be helpful and that the inspector would not care if there was caulk in the holes...it certainly would give if the slab were to heave.

I didn't think of the acoustical caulk at the time or I probably would have used it!

I wonder if you went to an industrial supplier and found some rubber bushings that would be the appropriate size for the nails and then drilled the holes in the top plate to accept the bushing in a tight press fit...

If there is a reasonable possibility that your slab might move, you might want to talk to an engineer about how much lateral support you need to consider in your nail holes to reduce the possibility of damage to the drywall. Where we are the ground is amazingly stable, so the only reason to build the floating wall is the building code...but after being forced to do it by the code, I expect that it is a good idea anyway from a sound transmission point of view!

I will try the test of knocking on the wall later this evening when I can have the assistance of my wife.

Tobe and Randy - thanks for the compliments! Our installation is so very basic compared to the very impressive things so many others are doing...when our ship arrives perhaps we will upgrade a bit!

Bob - We did the wall-tap test. I say tap because I realize that I rapped on the wall about like a polite knock on someone's door, rather than banging on it like the cops might. With no carpet on the concrete and nothing else in the room at all right now, every noise reverberates as though you are in a metal barrel!

My wife was upstairs and I first rapped on the wall of the guest room with her in the office above...she could hear it clearly (I rapped on both interior and exterior walls). Then I moved into the media room and she moved into the bedroom above it. She said that, yes she could hear my rapping, but if she was not expecting it and listening for it, she probably would not have heard it. A SIGNIFICANT difference between the two rooms.

One note I should pass on: The building department required that I add a fresh air inlet and a 60 cfm (minimum) exhaust fan to the room as it is a lower level room with no windows. At first I was a bit put out because it seemed excessive to require ventilation. Now I am thinking about replacing the 80cfm fan I purchased with one that moves more air! The equipment will be in open shelving in the mechanical room next door, but just the experience of working in the space makes me appreciate how closed up it is. (I installed a powered damper on the intake side so when the winter winds blow I would not be losing a lot of heat.)

Just figured I'd mention it.

Thanks, Aaustin!

Screen Height:

Tonight I am stressing about where to mount the 55" TV.

We got advice from the local high end stereo/HT shop that it should be centered about 5 feet off the floor (putting the bottom of the viewable area about 46" off the floor), but looking around on this site, I am thinking that most folks might say it should be lower???

My eye height on the furniture we will be using in the room is about 43" (my wife's is about 42") and we have no risers in the room.

Update...since I started typing this post, my wife came down and we decided to put the bottom of the TV at 40". That puts the top of the TV at 70" and we hope that it is a good height. (Center of the screen at about 55")

If anyone reads this post and thinks that this is a really bad idea, I won't get around to installing the bracket until tomorrow afternoon - so there is still time for us to reconsider!!!

Aaustin,

We purchased the TV prior to starting the construction of the room. I was suggesting that if we were going to build a dedicated room, perhaps we should go with a projector, but my wife said that she did not want to go that way. (Hey, she is the bread winner, the one who watches movies and the one who is the decorator...I guess she should have a vote!)

I did run power and an HDMI cable to where the projector would mount should we or the next owner want to install one in the future.

55" looked large to me until I started seeing the large screens that some folks are running!

Kurt,

Thanks for the input. It gives me confidence that the range of acceptable placement is broader than I thought...meaning that whatever height we choose is likely to be at least acceptable!

Right now the TV is sitting on a stand that came with it...on the floor! That puts the bottom of the TV 2 inches off the floor! It works...your 60" works, maybe I am in what my wife calls, "analysis paralysis".

I have not installed the mounting bracket yet - I am focusing on getting the project ready for the electrical final inspection. But I think I can be more relaxed about the exact height of the screen now. I just have to make sure that it is level!!