Strange Screen Project, Who Wants to Help?

[yourgrandma]

So now that I've more or less settled on getting an Optoma HD70 projector, I need to put some thought into my screen.

There are a few concessions I'm forced to make. First, since my HT is also my bedroom, I want to retain the ability to use my little 27". The solution I have for this is to simply hang the screen off the ceiling in front of the TV and my center channel speakers. Then, when not in use, it'll just lean up against a wall.

There are, as I'm sure you're aware, certain pros and cons to this. On the plus side, the screen will sit in plane with my front speaker array and I'll retain the functionality I want. But on the other hand, the screen will need to be accoustically transparent because the centers weill both be behind it. This in itself has some pretty nice advantages, but it complicates my screen building endevour.

I have yet to fully research the topic, but I'm posting this now, and checking for replys after I poke around the forum for some info.

I know there are commercially available screen materials that are acoustically transparent, but I've also noticed the price is a few magnitudes higher than I'd prefer paying.

My desired size is going to be a 74" diagonal, 36X64", with a throw of between 9 and 11 feet. My ambient light is well under control. So brightness shoulndt be a huge problem, right?

Thanks, I going to start reading now!

[cynical2]

yourgrandma wrote:

So now that I've more or less settled on getting an Optoma HD70 projector, I need to put some thought into my screen.

There are a few concessions I'm forced to make. First, since my HT is also my bedroom, I want to retain the ability to use my little 27". The solution I have for this is to simply hang the screen off the ceiling in front of the TV and my center channel speakers. Then, when not in use, it'll just lean up against a wall.

There are, as I'm sure you're aware, certain pros and cons to this. On the plus side, the screen will sit in plane with my front speaker array and I'll retain the functionality I want. But on the other hand, the screen will need to be accoustically transparent because the centers weill both be behind it. This in itself has some pretty nice advantages, but it complicates my screen building endevour.

I have yet to fully research the topic, but I'm posting this now, and checking for replys after I poke around the forum for some info.

I know there are commercially available screen materials that are acoustically transparent, but I've also noticed the price is a few magnitudes higher than I'd prefer paying.

My desired size is going to be a 74" diagonal, 36X64", with a throw of between 9 and 11 feet. My ambient light is well under control. So brightness shoulndt be a huge problem, right?

Thanks, I going to start reading now!

To get you started...there are a couple of tried-and-true acoustically transparent materials. One is Phifer Sheerweave 4500, another is SMX (which may actually be Sheerweave...I can't recall), and another is Center Stage - link, cost ~$140 (and there may be others...I'm sure folks will chime in). Keep in mind that there are voids in AT screens (could be holes, could be a weave), and you don't want the direction of the pattern to line up with the pixel structure from the pj. So, you should plan on ordering enough fabric to create the screen at an angle to the fabric pattern...anything over 15 degrees or so should be fine (you may not even need that much).

In the "stick my nose where it wasn't invited category": Would you consider mounting your screen high enough such that the center is just below the bottom of the screen? It would definitely open up your options regarding screen options. On a screen that size, you could slap together a laminate screen that would you give you a great picture for relatively little cost.

As far as brightness...not going to be an issue at the size you're after...even with AT material.

[yourgrandma]

Thanks, Jim, stickin my nose places it wasnt invited is a favorite hobby of mine, so consider this an open invitation.

Your suggestion would probably work alright for a single center, but I have two, one above and one below the TV. I would also like to have the screen as low as possible, thats just my taste.

Im looking at the setup right now and i might be able to get by with raising the top center above the TV a little bit, or just letting it hang out behind the screen and not worrying too much about it. Im going to grab the other screen we have thats made with BOM and see if it screws with the sound at all. Ill post my results momentarily.

[yourgrandma]

It didnt take more than 5 second of casual listening (i didnt even make it to my chair) to figure out that the BOM makes my centers sound aweful. It's like cupping your hand over the tweeters and putting a cardboard box over the mids. Terrible.
While in a practical situation it may not be as noticeable, I would never be able to live with that.

I'm pretty sure that if I build some sort of a stand to raise the top center and raise my screen, I can get by without needing an AT screen, thus saving myself a lot of money and aggravation.

This 96" screen looks pretty sweet in here, maybe I need a short throw lens. J/K, I like IMAX movies, but i dont think I've got the room.

Any thoughts on my size/throw setup? Is it typically better to lean to one end or another of the recomended throw length?

[cynical2]

As far as hanging a fixed screen, you may want to consider a hangman's mount. Would be easy to put up and down...and pretty forgiving.

You can make one yourself by just ripping a board on a 45 degree angle...mount one side to the back of the top of the frame and the other half to something hanging from your ceiling. If you decide to use a store-bought one (like in the link), then don't trust the "built-in leveling bubble"...they suck. Of course, something as simple as a couple of hooks hanging from the ceiling and eye bolts in the frame would also work (though it may tend to sway if a ceiling fan's on ).

[yourgrandma]

What I was going to do for the mount was a couple of chains screwed to the frame of the screen and eye hooks spaced slightly further apart on the ceiling. That way it could only sway back and forth, not side to side. And resting against the tv would probably keep it under control.
Thats a pretty interesting product, though, I've never seen that type of thing before, I might have to try that on some other stuff.

[cynical2]

yourgrandma wrote:

It didnt take more than 5 second of casual listening (i didnt even make it to my chair) to figure out that the BOM makes my centers sound aweful. It's like cupping your hand over the tweeters and putting a cardboard box over the mids. Terrible.
While in a practical situation it may not be as noticeable, I would never be able to live with that.

I'm pretty sure that if I build some sort of a stand to raise the top center and raise my screen, I can get by without needing an AT screen, thus saving myself a lot of money and aggravation.

This 96" screen looks pretty sweet in here, maybe I need a short throw lens. J/K, I like IMAX movies, but i dont think I've got the room.

Any thoughts on my size/throw setup? Is it typically better to lean to one end or another of the recomended throw length?

Generally speaking, I recommend erring on the size of going "big". You read pretty frequently about people that regret their screen size and want to go bigger...but rarely about the reverse problem.

In my theater, I have 2 rows of seating...one at ~11', the other at ~17'. My screen is 120" diagonal for 16:9 viewing and 148" diagonal for 2.35. So, it's significantly bigger than the "recommended" size given my viewing distance...but, my family likes it. I prefer the back row for 148" viewing and the front for 120". My kids (ages 10, 12) prefer the front for either size. My wife likes both.

How far from your screen will your seating distance be?

Regarding throw distance...generally speaking, for a given screen size, at minimum distance you will maximize brightness. At maximum distance, you will improve contrast ratio. I've experimented, and tried both with my Panny AX100U, and the differences don't seem all that noticeable to me (I think I see a difference, but it's not overwhelming...and, of course, you can't do a side-by-side). My input would be to try both, and see how it looks for your particular setup...I think you'll find it looks great at either end of the throw range.

[yourgrandma]

I'm going to be about 78-84 inches from the screen. pretty close for anything bigger than my goal, but I may try out some other sizes. I was planning on building a sort of hanger for the pj to mount to to get it off the ceiling and improve the angle and reduce the amount of keystone correction. Once its bolted up, it isnt moving. I'm not evensure I can get away with that, I might be stuck building a shelf at the back of the room, putting my screen size at an obsurd 100". While I cant deny the cool factor of that 96" i just took out of here, I think theres a point where youre trying to pack too much into a small space and it might not work out.

But who knows, that might be what I end up doing, the projector is suppoded to put out a good picture at that size and that would be the easiest rout to take as far as mounting is concerned, but it takes us right back to the problen of my centers behing behind the screen.

Im starting to think of a 37" LCD at this point, it'd be a lot faster.

[cynical2]

yourgrandma wrote:

I'm going to be about 78-84 inches from the screen. pretty close for anything bigger than my goal, but I may try out some other sizes. I was planning on building a sort of hanger for the pj to mount to to get it off the ceiling and improve the angle and reduce the amount of keystone correction. Once its bolted up, it isnt moving. I'm not evensure I can get away with that, I might be stuck building a shelf at the back of the room, putting my screen size at an obsurd 100". While I cant deny the cool factor of that 96" i just took out of here, I think theres a point where youre trying to pack too much into a small space and it might not work out.

But who knows, that might be what I end up doing, the projector is suppoded to put out a good picture at that size and that would be the easiest rout to take as far as mounting is concerned, but it takes us right back to the problen of my centers behing behind the screen.

Im starting to think of a 37" LCD at this point, it'd be a lot faster.

Don't give up so easy. This is the fun part! All of the possibilities in the world, just a matter of doing a good job choosing what suits you.

Can you give us some other dimensions?

Distance from rear wall to screen:
Ceiling height:
Room depth:
Room width:
Width of seating:
Height of center channels (with and without moving):

And any others you can think of...

A description of seating would be helpful (e.g. 3-person couch 2' from rear wall, etc).

[yourgrandma]

Distance from rear wall to screen: 12'
Ceiling height: 8'
Room dims: 12X14'
Seating is pretty much solo right now, just a single chair pretty much in the middle of the room. I might upgrade to a love seat so I can flop around more as I dont like sitting still, but it's usually just me in there.

Some pics and a scale diagram can be found here: http://www.hometheatershack.com/foru...stairwell.html

The screen is going in front of the front array, two feet from the front wall. The projector would probably go around a foot behind my seated position.

[cynical2]

OK, let's say, for the sake of argument that you settle on an 86" diagonal screen...

This is halfway in between the two you've mentioned (74" target and 96" test). Why 86"? I don't know...cause I think you'd like it best. Width of an 86" screen is ~74". Your seating distance would be about 1.1x screen width. Less than the "preferred" 1.5x, but I think 1.1x makes for a much more immersive viewing experience, without being so big that you feel like you're at a tennis match.

An 86" screen is 42" tall. Your pj's centerline (for a ceiling mount) is 1/3 of the screen height above the top of the image. So, from the centerline of the pj to the bottom of the screen is 56". The minimum height from the ceiling for the pj centerline will be about 4" (if you flush mount it). That puts the bottom of the screen at 60" from the ceiling, or 36" from the floor. Top of the screen would be 22" from the ceiling.

This scenario would leave no keystoning...how do those positions compare to your center location(s)? What height are they (and what height are you thinking you could move the top center channel to)?

How much sound quality does having the 2nd center channel add? Is it an option to only use one center (located on the video stand) during movie viewing?

I'm just throwing this scenario out as a "for instance" to better understand your obstacles. Once we completely understand the location of what you need to work around (like the height of your (center(s)), we can provide more input.


Jim

[yourgrandma]

The dual center setup is retty nice,especially when its impossible to have all the speakers in the frons on the same horizantal plane. It also takes some stress off the center, as mine may be a bit undersized.

Something I learned through setting up our other projector is that I much prefer having the screen as low as possible. It seems to mesh the audio with the picture best, and i really dont like having to look up to see the action.

I think the smartest thing to do would be to wait till i get the PJ and set it up on a latter ay different distances to see what size I;m going to need, I can use the exsiting BOM screen for testing, because I cant see going bigger than 96".

Are your figures for offset with the PJ level of with an angle to it? I dont mind a little bit of keystone correction, just not too much. Can I mount the HD-70 upside down?

[cynical2]

yourgrandma wrote:

The dual center setup is retty nice,especially when its impossible to have all the speakers in the frons on the same horizantal plane. It also takes some stress off the center, as mine may be a bit undersized.

Something I learned through setting up our other projector is that I much prefer having the screen as low as possible. It seems to mesh the audio with the picture best, and i really dont like having to look up to see the action.

I think the smartest thing to do would be to wait till i get the PJ and set it up on a latter ay different distances to see what size I;m going to need, I can use the exsiting BOM screen for testing, because I cant see going bigger than 96".

Are your figures for offset with the PJ level of with an angle to it? I dont mind a little bit of keystone correction, just not too much. Can I mount the HD-70 upside down?

I agree, there is no substitute for getting the pj in hand, and then shooting the image. For ceiling mount installations, yes...the pj is typically mounted upside down. I would think that with a ceiling mount there is no reason that you'd need any keystone correction.

As I mentioned, with a flush ceiling mount, the bottom of your screen in the scenario I gave would be 36" from the floor. With an 18" extension ceiling mount, you're at 18" from the floor. I can't imagine going any lower than that...and that range gives you NO keystone correction at all.

[yourgrandma]

SInce my PJ is on order and expected in a week, I should probably work on getting materials piced out for testing. The screen we currently have is made with black out material and performs well (as far as I can tell) but is decidedly NOT accoustically transparent. From what I can tell, the real stuff is real expensive, so I'm going back to the heart of this topic and asking if anyone knows of a DIY solution for minimal sound interferance at a reasonable cost. I have to imagine bightness will be of minimal concern, as my image size will be in the range of 72"-84" with a throw of around 10' and light control is complete. I realize it's taboo, but what of using bed sheeting? Is tyhe primary reason for avoiding that the fact that it lets too much light through, or the texture of the weave?

[mechman]

Have you priced out material only from SeymourAV?

mech

[yourgrandma]

No, sir. May I have a linkydoodle?
I s'pose I can google it, I just wanted to say linkydoodle.

Checking now...

[yourgrandma]

Holy smokes, that's cheaper than I thought it would be. a 68" wide swath the width I'd need would be $140.

So is this the good stuff, mech. Should I order it up? I'm trying to find where I can order a free sample.

[mechman]

There's a review here.

You can also pm chriscmore.

mech

[yourgrandma]

Wow, I didn't realize he was a member here. I sent him an email last night, but I might bug him on here, too, just to be thorough.

I'm pretty much sold on this stuff, I know $150 is on the high end for a diy screen, but I think it suits my needs very well, and I have to assume it will outperform any other option I had been considering.

[cynical2]

Ummm...yourgrandma...guess you didn't read Post #2...where I linked you to seymourAV and told you it'd be $140?

No worries...I miss things all the time.

[yourgrandma]

Hahaa. That's pretty sad that I'd skip right over it when I'm the one asking for the answers. Thanks to both of you then. I'll be in touch with Chris and we'll see where it goes.

Heh, thats ridiculous.