# New theater Design Advice...



## kepople (Sep 19, 2008)

We are building a house and I am looking for some advice on Acoustics. 
Details:
18'x18'x9' (its a cube)
Wired for 7.1
6 sconces, 4 recessed cans
Equipment wired to back
2 Large Klipsch Tower speakers
2 180degree rear speakers
1 large center channel
LFE 12" Sub
Dish network 1080P 
Apple TV with hardwired connection to Router
2 more Cat6 connections available, plus Wifi
room has no windows and can be controlled

Planning on:
Denon 2808ci or Onkyo 875
Sony HW10 LCD projector ceiling mounted, HDMI source
2 more Klipsch bookshelves for the rears eventually
Sony BDP 350 Bluray
Possibly a Mac Mini for a Media Server and Hulu viewing
Seating about 13' from screen for 4-6
120" Elune vison 1.3 

Please help with Acoustic treatment suggestions.
I will be builidng a stage, but probably not a false wall, and will put the tower speakers and center in in front and to the side of the screen.

I thought about doing 
-corner traps with the triangle foam, covered with speaker matierial. I am not sure if there is a benefit if the traps are not behind the mains, they will be just to the side of them...
-Building acoustic panels either in select areas or treating all the walls...
-Building a soffet with rope lighting about 8" down and filling with insulation and using speaker matierial on the bottem and wood on the sides. This was just for effect. Opinion?

What do you guys suggest? 
I have a 5.1 system in my living room already, but since this is a dedicated room, I wanted to make it sound as good as possible. I like the dead air sound you hear when you walk into a well treated theater and I wonder if the bass traps in the corners are enough to achieve a solid lively sound or if the whole walls need treatment?

Thanks for your advice
Kirby


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## bpape (Sep 14, 2006)

Hi Kirby

Welcome to the forum.

First of all, please don't use foam. Mineral wool, 3lb rigid fiberglass, or 3lb mineral wool are all FAR superior. Triangle traps floor to ceiling in the front corners will function well.

Front wall should be 100% dead in multi-channel. Whether it's 1" or 2" depends on other factors.

Side walls - probably 2" reflection panels - likely 3 or 4 on each side wall will bring the decay time in line. 

That's a pretty good start with the basics. We don't want to kill it too much but we want a balanced absorption scheme across the spectrum and proper decay times for the volume and usage. Most likely, the room could still stand some additional bass control in the rear on the wall to help mitigate the overlapping modal issues you'll have with the 18x18x9 dimensions. 

Placement of seating and subwoofer are critical so take some time to do some research as to the do's and don'ts and play with subwoofer position to get the smoothest response prior to doing any treatment.

If speakers and sub are on the stage, plan to build it VERY sturdy. Filling with sand is optimal - if not, then filling with insulation is next best. Leave it empty and have a weak top floor and it'll ring like a big drum.

Good luck.

Bryan


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## salvasol (Oct 31, 2006)

First of all ... Welcome :wave:




kepople said:


> We are building a house and I am looking for some advice on Acoustics.
> Details: *18'x18'x9' (its a cube)* ...Wired for 7.1 ...6 sconces, 4 recessed cans ...Equipment wired to back ...2 Large Klipsch Tower speakers ...2 180degree rear speakers ...1 large center channel ...LFE 12" Sub ...Dish network 1080P ...Apple TV with hardwired connection to Router...2 more Cat6...connections available, plus Wifi ...room has no windows and can be controlled
> 
> Planning on: Denon 2808ci or Onkyo 875 ...Sony HW10 LCD projector ceiling mounted, HDMI source...2 more Klipsch bookshelves for the rears eventually...Sony BDP 350 Bluray...Possibly a Mac Mini for a Media Server and Hulu viewing ...Seating about 13' from screen for 4-6 ...120" Elune vison 1.3
> ...


Cube rooms are one of the worst when comes to accoustics (I read it before, I'm not an expert okay).

If you can change the dimensions to avoid future problems I suggest you to do it (there's a rule to calculate the ideal dimensions; I think is 1:1.5:2.25 (9'x13.5x20.25) :yes:

You need to kill the whole front wall (use 2" fiberglass and cover with a transparent fabric or speaker cloth (fabric is cheaper I think) ... :bigsmile:

Corners traps don't have to be behing the mains ... you can use a panel, but if you kill the whole wall ... I don't think you'll need it.

You will need accoustic panel at the first reflection points ... unless you treat all walls (but I think it will be expensive; and I recall that Bryan (he is the expert on accoustic) recommends to evaluate the room to see what kind of treatment you'll need (absorption and diffussion).

Don't forget to fill all wall cavities with insulation, also, if you can use double drywwall ...:yes:

I will let the expert guide you from here ... what I'm suggesting is what I read on other threads :bigsmile: ... but every room is different :yes:


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## kepople (Sep 19, 2008)

Thanks for the advice.
So my screen wall needs the full insulation treatment or will heavy curtains due? Or both? 

The step Can be insulated, but I have seen a lot of build threads that dont. Makes sense. Can I use regular insulation or do I need to stack the 703?
Also how wide should the base traps in the corner be?
Kirby


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## bpape (Sep 14, 2006)

Curtains will help with high frequency issues only. There should be something behind them to deal with boundary issues and reflections in the vocal range as well.

Regular insulation is OK. Fill the whole thing - trust me. Also, double the top layer on the stage. 2 layers of 3/4" MDF works very well. 

Best bang for the buck also giving good performance is to have the corners be 17x17x24" triangles. You can cut 8 of these from a 2'x4' piece of 703. 

Bryan


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## kepople (Sep 19, 2008)

Heres the blank palette...

I cant really change the dimensions anymore other than taking away buy building a false wall for the screen. 
If I were to do that, would I be better to put the main speakers behind a hidden panel with the center channel?
I guess then I could put the traps behind the panel as well, however this will result in a room that is about 2 feet wider than it is long...

Since the rock is up, only the one outside wall is insulated, the others can be done with some panels which I can build myself. 

I saw a thread where the walls were covered with 2x2' panels made from wood, 703, and a canvas fabric. looked well executed. because I did not install the sconce locations, I will probably not be doing columns to hide the 7.1 speakers. Which is okay, I do have to build into the room a wall to hide the rack in the back since I already ran all the wires there preconstruction.

Thanks
Kirby

p.s. the wideanlge makes the location of outlets and such deceptive. You can tell in the photo that I had the sconces ahead of the estimated seating location and the box for the 7.1 speaker at the listeners ear.


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## bpape (Sep 14, 2006)

Adding a false wall won't do anything to change the physical room dimensions - only the visible ones. If the walls aren't insulated behind the drywall, I'd strongly recommend doing so.

Bryan


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## kepople (Sep 19, 2008)

Heres a shot with the plan so far.

Add to this the front wall will now be insulated with 2" 703 and covered with speaker matierial or canvas, black probably unless you think other wise. There will be curtains, wife wants them, but just roped back, not functional. Possible track lighting on the screen itself, and possible soffet for ceiling depth with rope lights. No stars I am afraid at the moment. 
ceiling color is not desided, but its supposed to be a dark color right?

kirb


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## bpape (Sep 14, 2006)

Ideally, all the surfaces would be darker colors. If you need lighter on the walls, a neutral grey (equal reflection of the 3 primary colors) is a good choice. Black front wall is excellent. 

Bryan


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