[andrewtodd]

I'm in the process of building a home theater. I haven't started a thread for it because I don't think it's fancy enough for anyone to care about it and I'm planning as I build.

One thing I've realized is that's it's hard to make decisions when the only person you've got to discuss it with is a wife who wouldn't care if you hung a 14 tv in the room.

This week has been a great example. The room is 19'L x 13.5'W x 10'H. I completed the platform for the second row of seating at the weekend. When sitting in the front row, with the seat pushed hard against the platform my ears would be 7' from the back wall. I did this on the advise of Bryan at GIK (who has been extremely helpful) so that the front row is best placed for acoustics.

The issue I now have is that the front row will be closer to the front wall than I'd like. My plan was to have an acoustically transparent screen sitting 2' from the front wall. Unfortunately that means the front row would only be 10' from the screen. Not only would that limit my screen size, I'm also concerned that I'd see the weave on the screen.

The alternative is to set the screen against the wall and place the speakers in some form of cabinets. Obviously this impacts the placement of the speakers.

Does any one have any suggestions are opinions of which route I should take?

 

[BIGmouthinDC]

use limited depth on or in wall speakers. You can build recessed pockets for the speakers to minimize the in room space requirement, You can do an AT screen with speakers behind in less than a foot. I think I could do one in 6 inches. A little surgery on the front wall may be required. but really nothing you couldn't knock out in a weekend.

Never put speakers in cabinets

Falcon and Seymour have newer tighter weave fabrics, you won't be able to see the weave.

 

[andrewtodd]

I may have to choose my speakers before going any further. I'm very interested in JTR 212-LPs (which are 12.5" deep) but I've never heard professional speakers outside of the local theater. I think I need to start looking for a demo.

I currently have Meridian speakers (17" deep) that I use for music. If I can find anything in my budget that is close in sound quality to them, they probably won't come into the equation.

I don't think cutting into the front wall is an option. I've already added a layer of drywall to the back wall to stop the sound getting out. The front wall is shared with the game room which is open to the rest of the house.

When I say put the speakers in cabinets, I mean something with open sides, back and front like the columns most people build to house rear speakers.

Thank you for the suggestions on the screen. After reading about them I'm going to refer to my original plan of putting the theater speakers behind the screen.

In your extensive experience BIG how much mill work can you get away with before it effects the sound. I really like the design of the theater in the attached photo but I imagine that theater is using far too much mill work at the front.

Thank you.

 

[drunkpenguin]

Did you mean 7" from back wall or 7'? If you meant 7 feet just move everything back some. I'm not sure what your plans are, but for me my back row has only been used a couple of times. Knowing that the front row would be the primary position I build everything for that row. The back row has compromises, but the 2 or 3 times I've ever had my theater full I sat back there so the guests could enjoy the front row experience. Something to think about.

 

[BIGmouthinDC]

when I say cut into a wall I don't mean through it, a wall has 4 inches of wasted space, you recess a 12 inch speaker 4 inches and you can get away with a 9 inch deep screen wall.

as for the amount of wood work, that door in the picture looks like the biggest problem. Aside from that, if there is treatment behind the screen that amount of treatment shouldn't be a problem, put it also shouldn't be 100% absorption.

 

[andrewtodd]

Did you mean 7" from back wall or 7'? If you meant 7 feet just move everything back some. I'm not sure what your plans are, but for me my back row has only been used a couple of times. Knowing that the front row would be the primary position I build everything for that row. The back row has compromises, but the 2 or 3 times I've ever had my theater full I sat back there so the guests could enjoy the front row experience. Something to think about.

The front row listening position is 7 feet from the back. Every decision I make is based on the front row. The second row will hardly ever be used. The front row will sit between 30% and 40 % back wall which is apparently the sweet spot of audio. I would have preferred to be sitting further back so I could increase the screen size but I've been told the seating position is very important for audio.

when I say cut into a wall I don't mean through it, a wall has 4 inches of wasted space, you recess a 12 inch speaker 4 inches and you can get away with a 9 inch deep screen wall.

as for the amount of wood work, that door in the picture looks like the biggest problem. Aside from that, if there is treatment behind the screen that amount of treatment shouldn't be a problem, put it also shouldn't be 100% absorption.

I didn't think there was ever wasted space when it came to sound transmission. I thought removing the 4 inches which currently holds R19 would have a audible impact on the amount of sound that gets out of the room. Is this not the case? I also assumed that placing the speakers in the wall will also have an effect.

Lets hope I like speakers that can be placed against/in the wall.

I have already built floor to ceiling corner bass taps in the 2 front corners (that was fun.) I was also advised to cover the entire front wall with 2" of OC 703 before measuring the sound. The back wall also has 3 bass traps (5.5' x 3.5' x 6") installed. The difference it has made to the sound already has far surpassed my expectations. I was going to test the sound first before deciding if/where I needed diffusers.

I currently have some flutter echo but I thought it would be pointless perfecting the sound until the room is closer to completion.

I was concerned that the amount of wood at the front of the room in the picture would reduce the effectiveness of the bass traps. Have you not found this BIG?

 

[andrewtodd]

Do you prefer Jeff to BIG? I'm so used to reading people referring to you as BIG that I rudely made the assumption it's the name you like to go by.

 

[sdurani]

The front row will sit between 30% and 40 % back wall which is apparently the sweet spot of audio. I would have preferred to be sitting further back so I could increase the screen size but I've been told the seating position is very important for audio.

If you can move your seating back so that the listeners' ears are about 1/3rd room length (6'4" from the back wall), that should put you at a location where problem frequencies are roughly the same level, giving you smoother frequency response.

 

[ChldsPlay]

If you can move your seating back so that the listeners' ears are about 1/3rd room length (6'4" from the back wall), that should put you at a location where problem frequencies are roughly the same level, giving you smoother frequency response.

Why do you want to increase the size? The experience is the same. You can spend more on a bigger screen and sit farther back if you want, but it's not going to be more immersive than a smaller screen that you're closer to. Figure out where to sit based on acoustics, then figure screen size based on that.

 

[andrewtodd]

Why do you want to increase the size? The experience is the same. You can spend more on a bigger screen and sit farther back if you want, but it's not going to be more immersive than a smaller screen that you're closer to. Figure out where to sit based on acoustics, then figure screen size based on that.

Although I have based my seating position on acoustics and will choose the screen size based on that, My experience is different with a bigger screen. Just walking into a room with a bigger screen feels different to me.

 

[ChldsPlay]

Although I have based my seating position on acoustics and will choose the screen size based on that, My experience is different with a bigger screen. Just walking into a room with a bigger screen feels different to me.

I can get that. It does have a different feel when you walk in. But the viewing experience won't suffer. But even if you're at 10 feet, you can still get close to a 120" wide 2:35 screen. That would only leave about 17 or 18" on either side of the screen once the frame is factored in. That's about 80% of the wall covered by the screen/frame. I think that's pretty impressive.

 

[andrewtodd]

I thought I was limited to about 84" across. I thought the ideal seating position is 1.5 times the size of the screen away. 120 is 1:1.

 

[BIGmouthinDC]

I thought I was limited to about 84" across. I thought the ideal seating position is 1.5 times the size of the screen away. 120 is 1:1.

True a decade ago. many old farts still think it's true.

 

[andrewtodd]

I should mention that I hadn't considered a 2:35 screen. I thought scanning left and right would be the biggest issue with being close and I was concerned with masking.

 

[BIGmouthinDC]

Do you prefer Jeff to BIG? I'm so used to reading people referring to you as BIG that I rudely made the assumption it's the name you like to go by.

I came out of hiding a long time ago and started using my real name as a signature. either works fine.

on the wall if you do an adequate backer box and seal the box well, losing the R19 will not effect the sound transmission. However hanging/mounting speakers on a wall will likely increase the overall vibration of the wall. You could rest the speaker on a rubber pad in the backer box to help. Is this a double drywall with GG or just a layer of DW?

 

[andrewtodd]

It sounds like I'm an old fart then. What is the best formula to follow now? I read that thx suggests 2.4 times the height. This still puts me at a 7 ft wide 16:9 screen but 120" (As ChldsPlay suggested) at 2:35.

Are more and more people getting 2:35 screens now? What percentage of movies are filmed at 2:35 and how distracting are the black bars when watching a movie in 16:9? I know I could get a screen that has motorized masking but I know they cost a fortune.

 

[andrewtodd]

The front wall is just a single layer of drywall with no treatment. I put 2 layers of drywall on the back wall because I was concerned more with sound leaving the house.

I was told that, because the studs are only separated at 16" green glue would have been a waste of money. There is no question that a lot of sound will escape but I wanted to keep it to a minimum.

Have you used a backer box on any of your builds that I can read about in the build thread?

 

[BIGmouthinDC]

Have you used a backer box on any of your builds that I can read about in the build thread?

I put the rear surrounds partially recessed into the wall at Rawlinsway.

 

[BIGmouthinDC]

It sounds like I'm an old fart then. What is the best formula to follow now? I read that thx suggests 2.4 times the height. This still puts me at a 7 ft wide 16:9 screen but 120" (As ChldsPlay suggested) at 2:35.

Are more and more people getting 2:35 screens now? What percentage of movies are filmed at 2:35 and how distracting are the black bars when watching a movie in 16:9? I know I could get a screen that has motorized masking but I know they cost a fortune.

 

[andrewtodd]

I put the rear surrounds partially recessed into the wall at Rawlinsway.

I found it thank you. That build is one of the ones I haven't spent as much time looking at. The woodwork is amazing.

This screen size business is confusing. If I base the seating distance on THX recommended height alone I'll get exactly the same picture size for 16:9 movie on a 2:35 screen as I would a 16:9 screen. Obviously the 2:35 image would be much larger.

- 2:35 screen size assuming seating distance is 10' - 52" H, 122" W, 132" D

If basing my measurements on the chart Jeff posted, my width would be more restricted. The 16:9 picture would be smaller on a 2:35 screen than it would on a 16:9 screen and vice versa.

- 2:35 screen size assuming seating distance is 10' - 42" H, 99" W, 107" D
- 16:9 screen size assuming seating distance is 10' - 55" H, 99" W 113" D

Are these calculations correct. The ideals seem to contradict each other to a certain degree but I assume that's because the width ideal is SMPTE and the height is THX.

I watch mainly movies so assuming I'm sitting 10' back (worst case scenario,) does it sound reasonable to choose something in the middle and go with a 2:37 screen that is 110' wide, or would it be safer to go with one that is 100 wide?

Either way I'm getting a much bigger screen than I had originally anticipated.

Thanks again for the help. I'm very please with the outcome of this thread.