# Dave's Theater Project



## DaveinGa (Feb 4, 2012)

OK ladies and gentlemen, here goes nothing! This is my first foray into a dedicated theater room and I need a ton of help! I am starting to frame the walls now and hope to solve my main problem before next weekend to finish the framing then. My goal is to do an acoustically transparent setup in my room with a 160" screen. I am unsure how to construct the screen wall and what to do with the concrete wall that will be behind it. Here is a pic of my wall with a view of trying the size of the screen out.








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## DaveinGa (Feb 4, 2012)

How is the decision made to go with a straight vs curved screen? I have seen some great looking examples of what I am trying to do on here but, now that I need them, of course I can't find them... There was one thread that had the perfect setup in my mind with a black wall full of speakers behind the screen anyone familiar with whose that might be?

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## bpape (Sep 14, 2006)

How big is the room?

How did you arrive at a 160" screen?

I would wall over the concrete with studs and drywall, then construct an open stud wall (no drywall), mount the screen on that, the cover the balance with AT cloth like GOM FR701-2100.

Are you planning at AT screen also? 

What speakers are you using?

Bryan


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## DaveinGa (Feb 4, 2012)

The area for the theater is 28 x 18 right now, if i build a false wall i am unsure how much i will lose, 3' maybe?
I just liked the size of a 160" screen the best, in the photo is actually 172" (both 16:9) I have plenty of room to get back from the screen if need be and really wanted the biggest screen i could get in there! from what i have been reading, if i understood correctly, 18' is far enough for this size screen is it not?
I am planning to go with Klipsch speakers currently unless I get many opinions against them on here, I have not seen them mentioned much so far but, have heard them and liked what i heard.
Here is a link to my google sketchup of my theater dimensions as they stand currently

cant get it to work, probably user error... I will try to add link later...

Thanks for the advice on the screen wall, I will go ahead and build the back wall and hold off temporarily on the screen wall.


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## Prof. (Oct 20, 2006)

DaveinGa said:


> How is the decision made to go with a straight vs curved screen?


A curved screen is not a necessity and comes down to personal choice..If you plan on using an anamorphic lens, then depending on throw ratio, you may need to curve the screen..


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## DaveinGa (Feb 4, 2012)

As I understand the anamorphic lens it is for use with a 4:3 projector, to "stretch" the format to 16:9? I never watch any native 4:3 material that I can think of so, I would not need one correct? I would definitely prefer a straight screen in my theater if possible. I have built all the walls but the front now and hopefully by the time I start framing again next week I will have a plan for it as well. Thanks again for the great forum gentlemen!

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## Prof. (Oct 20, 2006)

DaveinGa said:


> As I understand the anamorphic lens it is for use with a 4:3 projector, to "stretch" the format to 16:9? I never watch any native 4:3 material that I can think of so, I would not need one correct?


Not correct!..The anamorphic lens is designed to work with a !6:9 native projector..

When playing a 2.35:1 movie, the image is vertically stretched by the projector to eliminate black bars top and bottom..The lens then optically stretches the image to the full width of the screen..
The end result is that you don't lose any pixels, whereas if you zoom the image to fill the screen, you're losing about 30% of the total pixels..


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## Mark Techer (Jan 17, 2008)

bpape said:


> How big is the room?
> 
> How did you arrive at a 160" screen?


I will assume he has just zoomed the projector to see how large an image he could get and decided that was good.


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## Mark Techer (Jan 17, 2008)

To be a little more constructive here.


DaveinGa said:


> The area for the theater is 28 x 18 right now, if i build a false wall i am unsure how much i will lose, 3' maybe?


It will depend on how you build it, but 2 to 3 feet is normal, which leaves you with 25 feet. 


> I just liked the size of a 160" screen the best, in the photo is actually 172" (both 16:9) I have plenty of room to get back from the screen if need be and really wanted the biggest screen i could get in there! from what i have been reading, if i understood correctly, 18' is far enough for this size screen is it not?


Image height is 25/4 = 6.25, so if you rounded down to 6', then yes 18 feet or 3x the image height is perfect. I wish I had the space to do one the same size.


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## bpape (Sep 14, 2006)

18' from the front wall for the seats is a pretty good general place acoustically. If you then move the false wall out say 2' or so, the screen to eyes will be approx 16'. Don't make the mistake of letting screen size drive seating position. Seating position comes first, then you decide the screen size that works at that viewing distance.

Bryan


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## Mark Techer (Jan 17, 2008)

bpape said:


> 18' from the front wall for the seats is a pretty good general place acoustically. If you then move the false wall out say 2' or so, the screen to eyes will be approx 16'. Don't make the mistake of letting screen size drive seating position. Seating position comes first, then you decide the screen size that works at that viewing distance.
> 
> Bryan


Bryan, can you please explain your reasons here? To me, this is clear cut case of which came first, the chicken or the egg and where in this case the chicken laid the egg. You need to have a chicken (the room) before you can get eggs (screen size and or seating position), but I am open to other suggestions.


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## bpape (Sep 14, 2006)

Correct. You need a room. In that room, there are good and less good and bad places to sit. Sit where you'll get the best performance and then select a screen size that has the viewing cone you want. Just saying I want the biggest screen and then allowing that to force a bad seating position doesn't make sense.

You can get the same feel of immersion by sitting closer to a smaller screen than farther away from a larger one. Unless, you're just looking for bragging rights on having a huge screen 

Really doesn't buy you anything except worse audio performance, spending more money, having to buy a light cannon to get decent brightness on the larger screen, etc.

Bryan


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## Mark Techer (Jan 17, 2008)

bpape said:


> Correct. You need a room. In that room, there are good and less good and bad places to sit. Sit where you'll get the best performance and then select a screen size that has the viewing cone you want. Just saying I want the biggest screen and then allowing that to force a bad seating position doesn't make sense.


It is once again chicken and egg. For a 2CH audio only system, I agree because you could place the speakers where ever they needed to be to sound their best. When you are designing a large screen HT, you need to know where your speakers are going to be in relation to that screen if you want sound that actually matches your picture - this goes beyond left speaker being on the left side. 

I am dealing with a guy right now - not a clue, but very fast to tell me what he thinks he wants, even if that is not entirely practical much less even achievable. His room can support a 140" (dia) Scope screen max, yet he wants a 150 or 160 plus seating for 4 with 9.1 audio. I've drawn his room up and it just does not work at those sizes. 140" is at least do-able. 



> You can get the same feel of immersion by sitting closer to a smaller screen than farther away from a larger one. Unless, you're just looking for bragging rights on having a huge screen


Sorry I have to disagree with that because if that was the case, none of us would have bothered with projectors. We would just huddle around the TV. I can sit 2x the image height in my home cinema and it is very enveloping. If I was to sit 2x the image height at the cinema, it is a very different experience (even though the angles are the same) it is even over whelming. I have a friend with a 150" Scope screen and I love it at 2x the IH. When I go back to my own room, even though the angles the same, I don't feel I get the same impact because I know the image is smaller. Your brain just knows there is a size difference. 

In this case, the OP wants the largest screen he can get. 



> Really doesn't buy you anything except worse audio performance, spending more money, having to buy a light cannon to get decent brightness on the larger screen, etc.


Light cannons are cheap these days. 
Like everything in life - there are levels of compromise one needs to accept.


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## Prof. (Oct 20, 2006)

I think Bryan and other Audio and Video specialists base their equations on long tested specifications for viewing and audio requirements, designed for widescreen viewing..ie a 16:9 AR..
These specifications work well with 16:9 screens, but Scope screens are a whole new ball game..in particular anamorphic projection and AT screens..

General seating distance is much closer with a scope screen and with quality equipment can be as close as 2x the screen height..

From the audio point of view..If one is using an AT screen, L&R speakers can positioned behind the screen to form the ideal triangular position, appropriate to the viewing distance..

Sitting close to a smaller solid 16:9 screen with speakers at the sides may give an immersive effect, but certainly not ideal for audio..


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## Mark Techer (Jan 17, 2008)

Prof. said:


> I think Bryan and other Audio and Video specialists base their equations on long tested specifications for viewing and audio requirements, designed for widescreen viewing..ie a 16:9 AR..
> These specifications work well with 16:9 screens, but Scope screens are a whole new ball game..in particular anamorphic projection and AT screens..


You might remember a room calculator that showed seating distance for 36 degree viewing angle. The screen options were 4:3 or 16:9. 36 degrees is actually the preferred angle for CinemaScope 2.39:1, not 1.78:1. yet many people designing rooms for HT still refer to that calculator. 

If you can’t change it, change how you think about it.



Prof. said:


> General seating distance is much closer with a scope screen and with quality equipment can be as close as 2x the screen height..


The beauty of Constant Image Height is that 2x for Scope is also the ideal place for 16:9 and 4:3. It is when people take the 36 degree viewing angle for 2.39 (which is about 1.54x the image width) and apply that to the 16:9 screen that the image height is now too tall (about 33% too tall). 



Prof. said:


> From the audio point of view..If one is using an AT screen, L&R speakers can positioned behind the screen to form the ideal triangular position, appropriate to the viewing distance..


Well lets look at that. Right now THX are pushing for 45 degrees between the L and R speakers. That angle used to be 60 (introduced by the ITU-R), but it was accepted that 60 was too wide if the sound has to match a picture. Based on a distance that uses 45 degrees for the separation of the speakers, a solid 16:9 screen can be used with the speaker just outside the edges. 

If the solid 16:9 screen is replaced with an AT 16:9 screen, the only thing that changes is that the centre speaker can now be placed behind the screen. If the 16:9 screen is now replaced with an AT Scope screen, the only thing that has changed in the size (width) of the image. The speakers are still at 45 degrees apart. my point being (and back to the chicken/egg thing) is how do we know what is ideal for a room unless we actually plan for that room.

All I suggested was that OP plan ahead by knowing how much space (depth) he had to work with after the baffle went in. He was already experimenting with finding the largest image possible, so by suggesting a 6 foot tall image is actually closer to what he wanted originally. He wants to sit at 18 feet and 6 x 3 = 18. Perfect! Will it be perfect for the audio? Probably not, but as I said, there has to be levels of compromise we must accept. 




Prof. said:


> Sitting close to a smaller solid 16:9 screen with speakers at the sides may give an immersive effect, but certainly not ideal for audio..


That can depend on the application. If I am using PC speakers next to lap top, I can create the same scenario of speakers outside a solid 16:9 screen spaced at 45 degrees. And it works because I am the only one listening and watching the screen. Is it enveloping? No, but sounds are heard in the same locations that they would be heard in a larger scale HT set up that also uses a solid 16:9 screen and 45 degree spacing of the L and R speakers.


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## bpape (Sep 14, 2006)

Up to you but it's not chicken and egg at all. Even with 2 channel, you still sit in a good place - then you place the speakers where they'll work best in relation to the wall behind them and adjust the side to side spacing to fit your distance.

And... I wasn't suggesting huddling around a TV. My point was that you might get by with a screen that's say 10-15% smaller - hence 10-15% cheaper and 10-15% brighter with the same PJ without cranking the output and kiiling black levels. All that and better sound too. What's not to like?

Bryan


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## Mark Techer (Jan 17, 2008)

bpape said:


> Up to you but it's not chicken and egg at all. Even with 2 channel, you still sit in a good place - then you place the speakers where they'll work best in relation to the wall behind them and adjust the side to side spacing to fit your distance.


The OP's room is pretty much a blank canvas, an empty space with potential to be great. Where do you suggest he start? He already expressed in an earlier post that he wants a big screen. I did the math (I've been using since 2003 and he can have a 6" tall if he wants (and if he can light it). If he goes AT, he also need a baffle wall. These kind place heavy restriction as to you finding a 'good place' which is why I always start with a screen height.


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## bpape (Sep 14, 2006)

Generally, somewhere between 33 and 38% of the room length is a good rough starting point. Certainly enough to get a ballpark idea of screen size that is appropriate.


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## DaveinGa (Feb 4, 2012)

You guys really do know a lot about this stuff! I seem to need to give a little more info, I am looking to do a theater that guys like you would walk in to and say wow, best of everything (getting some help financially) when you say "if he can light it" I assume you mean projector quality, the one I have now is not permanent just one I swayed for a plasma tv for the fun of it. I have a google sketch of my room but, I can't figure out how to put it on here, any suggestions?
I have decided I definitely want the AT screen and baffle wall, too clean to hide the rakers and audio from the image seems like a smart idea. It sounds like pricing of equipment is the main limitation here so I will lay out what I think I will be spending so you have an idea what to suggest
Speakers. . $12000
Audio equipment $5000
Projector. $5000
Screen. Unknown but, alot?

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## Mark Techer (Jan 17, 2008)

DaveinGa said:


> You guys really do know a lot about this stuff!


I probably could get away with saying I know enough, but I will admit, I am still learning about wall construction as the building codes here (Australia) don't seem to show double studded wall etc. We also have nogs which all the diagrams on these walls I've seem to not have. 



DaveinGa said:


> I seem to need to give a little more info, I am looking to do a theater that guys like you would walk in to and say wow, best of everything (getting some help financially)


You've come to the right place. Yes the more info you volunteer, the better the end result will be. 



DaveinGa said:


> when you say "if he can light it" I assume you mean projector quality, the one I have now is not permanent just one I swayed for a plasma tv for the fun of it. I have a google sketch of my room but, I can't figure out how to put it on here, any suggestions?


Many of the projectors on the market or not 'bright' and if you want to light up a big screen to at least 14FL, you will need some series lumens to do so. having said that, there are now some 'affordable' light cannons out there. Previously you would have been limited to data grades or the high end market. 



DaveinGa said:


> I have decided I definitely want the AT screen and baffle wall, too clean to hide the rakers and audio from the image seems like a smart idea. It sounds like pricing of equipment is the main limitation here so I will lay out what I think I will be spending so you have an idea what to suggest
> Speakers. . $12000
> Audio equipment $5000
> Projector. $5000
> ...


The look you get from an AT screen is very clean and has high WAF. You can't really go placing your gear behind it though because if there is any lights, you see them during your movie. How would you like to mount the projector? Whilst lens shift is getting more and more popular, there seems to be trend in some units where they have greater vertical down shift than up. This means that these projectors are better suited to a high shelf mount rather then the more tradition inverted ceiling mount. I am not a fan of the pole mount. 



bpape said:


> Generally, somewhere between 33 and 38% of the room length is a good rough starting point. Certainly enough to get a ballpark idea of screen size that is appropriate.


Thanks for that. How would you do a screen size? 

Also, is this how I do a double stud wall? I wasn't sure about the corners. Sorry for the Metric. Do the base plates really touch or should they be isolated as well?


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## bpape (Sep 14, 2006)

So now in addition to the very large screen, it's going to be AT also which can be even more of a brightness problem. I would really, really seriously rethink something that large for a whole variety of reasons.

As for the screen size, based on that rough seating position, you can look at it from both the minimum 36 degree included angle and from the constant height theory.

Bryan


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## Mark Techer (Jan 17, 2008)

Depending on the fabric, he can get a good result. The original SmX (2 x 2) weave works better at large screen sizes and the new "4K" (1 x 1) weave is even better. Yes AT screens do let light pass, but the issue is more about reflected light coming back through and why he also needs a baffle wall.


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