CurtPalme.com Home Theater Forum

[wally_01]

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I'm thinking of setting up a home theater in my basement and this is all new to me, so I could use some advice.

The dimensions from the screen area to the projector is about 20'. The max screen height without some serious modifications is 6-7'. I don't think the width is going to be an issue as that is about 12-14'. The room is fairly dark as I will be taking out the only window to install the screen. Mainly to be used for watching DVDs.


The ceiling height is a little low at about 7'. I want the projector to be "permanatly" mounted as I don't want to deal with adjusting it anymore than absolutely nessicary.


After doing some research I'm thinking about going used CRT, but not sure if I need that or to what level (good, better, best) do I need to be looking for???????????????? Also any advice on screen material would be helpful.



Thank you

[Nashou66]

Budget?

Athanasios

[garyfritz]

Be aware that CRTs hang down from the ceiling a foot or more. Your 7' ceiling is going to result in a pretty low projector. For me (I'm 6'4") that would be serious head-knocking height.

Because of their optics and the lack of a zoom capability, CRTs tend to hang at about (1.3 - 1.5 x screen width) away from the screen. That tends to be just about where you want to sit, too. More head-knocking to think about.

That 1.3 - 1.5x screen width puts some limits on you, too. Assuming the BACK WALL is at 20', that means your lenses are going to be at about 17'. That means the max screen width is about 12'. A 2.35:1 screen would be 12x5.1. 5' is a good height for that room -- you don't want the screen to go all the way to the floor.

12x5.1 = 61.2 sq ft. A typical projector like my Marquee 8500 throws about 1200 lumens (peak) on a 4:3 screen, 900 on a 16:9, 685 onto a 2.35:1. (With the wider aspect ratios you use less of the tube face so you're lighting up less phosphor.) 685 lumens / 61.2 sq ft = 11.2 foot-lamberts (ftL) on your screen. That's a good brightness range. Bigger screen sizes would reduce your brightness.

By comparison my Marquee 8500 puts out 1200 * .75 = 900 peak lumens onto a 85 sq ft 16:9 screen, or 10.6 ftL, and it's barely bright enough for my tastes. And I've got a 1.25 gain screen, making it effectively 13.25 ftL.

With a high-gain screen you could boost the perceived light levels, but then you have hotspotting issues unless you make a torus (curved screen).

Given your ceiling height issues &etc, I wouldn't go any bigger than 5' high, especially if you want a second row of seats. You could sit about 13-18' back, depending on how big an image you like. That range would work well for two rows of seats, if you were planning that. (But with a 7' ceiling you'll have trouble raising the second row enough to see over the front row, especially if the screen goes down near the floor. The CRT will also start to block the second row's sightlines.)

So that gives you some things to think about... See the attached pic for an example of how the sightlines work out. That assumes a 7' high room, 20' long, CRT lenses 1.5x from a 11.75x5' screen. The front row is at 1.25x, which is really close. And the two rows are really cramped. I've got them only 4' apart, and I think most people use 6', especially if you use recliners. It would work a lot better with a slightly smaller screen, unless you only want one row.

If you really want a ginormous 14' screen, I would suggest you look at some high-lumen digital projectors instead of CRTs. They'll throw a lot more light onto that big area, they won't hang down from the ceiling as much, and they have zoom lenses & thus more options for hanging location. But consider that with a 14' screen you can only have one row of seats. The back wall is only 1.4x from the screen, and that's fairly close for most people.

[jeffslife]

thanks for the info