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Discussion Starter · #1 ·
My theater front wall will have the dimensions of 14.5' wide x 8.5' tall (without soffit).


I want to have a front soffit above the screen that also contains my Paradigm CC-350 center channel of the following dimensions:


Height, Width, Depth 7-1/2 x 22-3/4 x 10-1/4in


I have the 75u Panasonic projector (just purchased, wheeeee).


What would be the best size screen 16:9 or 4:3 to fit within these parameters, and how big should/could I make the soffit, so that I don't have any problems with the speaker close to the ceiling.


Thanks for any and all help
 

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Robert,

The decision of 16:9 or 4:3 shouild be based on the projector's aspect ratio and your choice of viewing material and not just to fit a particular space. Once you pick an aspect then you can pick a size.


For instance I have a Sony 10HT it's a 16:9 JP to use a 4:3 screen would not have made sense. On the other hand if you have a 4:3 PJ and you are planning for mostly widescreen movies maybe a 16:9 makes sense. If you are gaming then 4:3.
 

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Discussion Starter · #3 ·
Jim,


thanks for the response....I've done quite a bit of reading on the subject, and there are definitely two camps when it comes to 4:3 or 16:9. I would like a 4:3 screen and do vertical masking only for the different ratios, however, I don't think I have the height to get the width that I would want. So, I'd probably go with a 16:9 screen. Most of the viewing will be DVD anyway, so maybe that makes sense.


What's not evident, is how far the bottom of the screen can be before being obscured by the front row, and how far the top can be without the top edge being obscured by a soffit, etc. I have plenty of room to move the projector back and forth to fit the screen, but I think the dynamics of the screen wall and the aforementioned circumstances will likely drive how big the screen is.


So, given a 14.5' width, and let's say 7'6" tall to the bottom of the soffit, would a 9x6 (roughly) screen fit okay? If I positioned it 6" below the bottom of the soffit, that would make it 2' off the bottom of the floor. It would give me roughly 2.5' on either side of the screen for columns to hold my speakers. Sound Okay????
 

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Quote:
Originally posted by Jim Mc
If you are gaming then 4:3.
Actually Jim, it depends on what kind of gaming you are talking about. If you are talking about PC gaming, then go with 4:3. But game systems can be different. The newer systems like PlayStation2, XBox, and I believe GameCube, all can be switched to 16:9 ratio.


Robert, I'm no expert on this, but usually people go by viewing distance and equipment to pick a screen. I've read several different opinions on what formula to use, so I won't even try to tell you what size you should go with. A search under maybe 'Screen Size' would be a good place to start. Once you've figured out what screen size to go with, then start checking if it would fit. OR, you could just skip the formulas and buy the size you like. Also, I don't think you said whether it's a fixed or electric screen. Electric screens usually have around 15 inches of black fabric between the case and screen.



Here's a question I have while people are asking about this. Assuming you just have one row of chairs, how do you determine how high to mount the screen on the wall? I'm planning on probably a 120" diagonal 16:9 screen. I would assume you would want to put the center of the screen close to eye level so it's comfortable to watch. I was planning on a soffit or something above the screen for the center channel and was trying to figure out how high to build it. But I can't figure that out without knowing how high the screen should be from the floor.
 

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Discussion Starter · #5 ·
Quote:
Originally posted by Toxarch



Here's a question I have while people are asking about this. Assuming you just have one row of chairs, how do you determine how high to mount the screen on the wall? I'm planning on probably a 120" diagonal 16:9 screen. I would assume you would want to put the center of the screen close to eye level so it's comfortable to watch. I was planning on a soffit or something above the screen for the center channel and was trying to figure out how high to build it. But I can't figure that out without knowing how high the screen should be from the floor.
Hey, that's not your question, that's mine ;)


You just worded it better :)
 

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I would say check the throw distance information for your pj. The height of the screen may be dictated by the image size and how your projecting the image (ie. ceiling vs table mount).


For example: You know the size of the image you want. So you know how far back to mount your pj. Then based on how the projector throws the image will determine the distance from the center of the image to the top.


Andy
 

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Robert,

A 120" 16:9 screen would be ~9' x 5' or more accurately 106" x 58" viewable area that is what I have.


My room is 14'5" wide and 21'3" deep. At the screen with ceiling steps I have 7'2" floor to ceiling my screen top is 6'10" off the floor and the bottom is 24" off the floor. The top of my center is 26" off the floor but since the center is about 2 feet forward of the screen the viewing angle down to the screen bottom places the center visually below the screen.


To put a 58" screen centered on the eyes of the first row would place the screen only a few inches maybe 6" off the floor.


My seating is at approx 13' & 19' with the second row riser being ~ 12" high.


If you want to model the viewing angles in your room here is how I did so. Grab some push pins and string. At the screen wall mark the proposed bottom of the screen on the side wall. Make a mark about 40" (top of seated viewers head) even with your first seated row on the side wall. Now project a line back from the front mark over the middle mark toward the rear. This will give you a good idea of where the second row viewers eyes need to be. Lower the screen eyes go up raise the screen eyes go down. Push the first row back and second row eyes go down.


Andy is also correct that your PJ and it's mounting will also be a factor to deal with in determining screen placement.
 

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Discussion Starter · #8 ·
Thanks guys...


Jim,


It took me a couple of readings to understand what you were saying, but I've got it now...Just extending the line of sight to determine how far back/high the second course needs to be in relation to the first course in relation to the bottom of the screen.


I might also try the brute force approach...I'll cutout a piece of something to the screen size I want, pin it to the wall, and project an image...Play around with projector location to make sure everything fits. Play around with screen position also...Then finally play around with seating as Jim suggests.
 

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I'll field the center channel in the soffit question.


One issue of mounting the center channel near the ceiling is the comb filtering that results from the direct wave and the reflected wave having a relatively short timing difference. The relatively short timing differences will result in a filtering effect that reduces dialog intelligibility. Those interferences (constructive and destructive) are also what cause the boominess typical of mounting near a wall as well as the timbre changes that result. Your crossover points and the dispersion pattern of the speaker will affect the needed distance from the boundary. If you have some control over mounting locations, you may want to consider going behind the screen and using a perforated screen. Aligning the center speaker so that more listening positions have a nearer to on-axis response is desirable in most applications, plus you benefit by aligning the center channel (primarily dialog) with the image on the screen, and you also benefit by being able to align the front three speakers horizontally and at an ideal height. You should audition the perfed screen to see if it's acceptable to you from a video standpoint. If you're dead set on the soffit mount, some things that will help are to make sure that the soffit is flush with the speaker's front baffle, and angle the soffit so that the axis of the center speaker will be aimed towards the listeners. That will help to reduce part of the boundary effects, but again there are several factors to consider before determining how effective it will be (including the construction of the soffit). You may want to contact the manufacturer to see what their recommendations are, since different manufacturers will adjust speaker design based on where they think the speaker will be placed (or recommend speaker placement based on their design). Keep in mind that you may have serious timbre changes between the various speakers based on how you engineer the room.
 

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Discussion Starter · #10 ·
John,


It's either in the soffit above the screen or below the screen. Due to the human ability of localizing sound below the horizon, I was hoping to stay with above and in the soffit. Sure, a perf'd screen would be great, but that introduces other effects, since no screen is accoustically transparent. Not to mention the effect on my wallet.


So, I'll likely go with the soffit construction. I'll be sure to build the hole such that the front of the speaker is flush with the front of the soffit. I'll also construct an angled sill plate so that the speaker is aimed at the listening positions.


Beyond those two great pieces of advice, you mentioned there are other things to be considered in the soffit construction. I had planned on framing it out with 2x4's, ladder style, with plenty of support and covered with MDF and then fabric. I would fill the soffit with fiberglass batting. What would be the best way to secure the speaker in the soffit to eliminate rattling and vibrations. Should I isolate it with rubber feet? Thanks for the great help.
 

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Jim mounted his screen 24" off the floor. But he has 2 rows. I just plan on having a sigle row. I guess people just put the screen wherever they want.
 

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Yep 24" off the floor.

Why?

Both rows have a good sightline.

Plenty of room for a center below the screen on a nice stand.

My front screen wall is visibly 7'2" tall, with a hidden pocket for my moving masking system to retract into.

When reclined your sight angle becomes slightly elevated.

It worked for me.
 

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The bottom of my screen is around 27 inches off the floor. I have a ceiling mounted 16:9 Draper Targa electric screen so the screen housing took up some space. The ceiling is 91" high, the housing is 8", and my screen is 52" high plus 4 inches for the black border. So you add all that up (8+52+4) and get 64". Subtract that from my 91" ceiling height and that leaves me with 27 inches.


That puts the center of the screen about 55" high which is a comfortable height for viewing when slouching on the comfy couch. I felt going lower would be too low (not to mention my feet propped on the cocktail table would be in the way). :)


Andy
 
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