CurtPalme.com Home Theater Forum

[incova]

Hi guys, I am thinking of the future here, or dreaming maybe lol, how large a room would you need for a pair of PJs blended and what would be the optimal screen size in metric?

[Tim in Phoenix]

Hello

The cool thing about edge blending, besides obscene light output, is the very small footprint, since your throw ratio is 1.0 to 0.95 depending on the screen aspect. I sit behind two table mounted 9500s filling a nine foot screen width in a seventeen foot depth no problem.


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[AnalogRocks]

[AnalogRocks]

[Tim in Phoenix]

[incova]

this is why I didnt go for chains furlongs etc funny guys! lol

[incova]

What was the size of Ginos screen?

[the big E]

[Nashou66]

4.1148 meter screen but for now only using 3.5 meters till I upgrade to 9 inch tubes.





Nashou

[the big E]

[Tim in Phoenix]

Guys

More pictures here: https://www.curtpalme.com/forum_archived/viewtopic.php@t=24105.html


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[km987654]

[Nashou66]

Km, i used the Hurley screen. I think the mw 16 i can't remember the exact model number off the top of my head.

Nashou

[stefuel]

Even the smallest dumpster will hold two projectors with plenty of room to spare

[mc86]

To the OPs Q regarding how large a room size do you have to have for a blend...seems to me this is backwards. That is, seems like the question should be: How large does a room and screen have to get before a blend is desirable for a given PJ? This gets at brightness, spacial resolution/visual acuity, viewing distance, viewing angles (horz and vert), and other stuff that depend on room geometry. Sitting distance vs seating distance, primarily.

Without having worked the out what the brightness or spacial resolution would be, I'd *guess* the answer for CRTs is that each inch of tube can support an additional 20" (0.5m) width. Thus:
7" machine shouldn't do much bigger than 80" (2.1m) wide [and cannot do less than ~45" (1.05m)?]
8" machine shouldn't do much bigger than 100" (2.5m) wide [and cannot do less than ~50" (1.25m)@8ft (2m) throw?]
9" machine shouldn't do much bigger than 120" (3m) wide [and cannot do less than ~60" (1.5m) @9ft (2.25m) throw?]

Assuming this rough guesstimate works OK, the room DEPTH (sitting distance) would be determine based on trying to achieve something like a 30 to 36 degree viewing angle. There is a nice set of charts here:
http://www.avsforum.com/t/1004723/chart-distance-x-screen-size-standards-smpte-and-thx

Taking my room as an example, distance from screen surface to seating area is just under 14ft (4.2m). My 80" (2m) screen is 14ft away and this gives a 26degree angle. It is so small as I have a 7" machine. I'd like 100" (2.5m) screen to get to 33degrees -- a 9" machine ought to do a 100" screen really well and an 8" machine OK.

Most on here will agree with the above, BUT will say they want things brighter! This is nothing to say about maintaining the correct vertical viewing angle and the amount of keystoning on the tube face that a closer mounting (and vertical angle) would demand (without raised seating). In my case, a blend also increases the resolutions I can support.

A 7" machine can handle 80" (2m) wide at can do 1080i at OK brightness. Two 7" machines will do 1080p AND with more brightness AND at a desired viewing angle with a ~100" (2.5m) screen. Who knows if the convergence/geometry can be adjusted sufficiently or stable enough to make a go of a blend with 7" machines, but I'm hoping 2 ECPs will *begin* to approach one G90 when setup for 100" image. Should look a crap-ton better than one ECP.

BTW, folks need to be careful on assuming a blend simply enables one to go big and gaining brightness, too. Going from a 2m wide screen with one PJ to 3m screen with two PJs actually results only in a moderate brightness increase. That is, the area of the screen more than doubles in going from a 2.4:1AR @2m width to the same AR at 3m width. Meanwhile, the light output goes up maybe ~3X (2.4:1 portion of one 4:3 TO 90% of both PJs in 4:3 AR).

Sorry if these musing aren't fully informed, but I'm happy for my thoughts to get straightened out and kicked around by others...

cheers,
Matt

[Tim in Phoenix]

Guys

Two ECPs are not a preferred starting point, but they are a start. A 1.0 gain screen fabric is required, so it is equally bright off-axis as it is on-axis.

With one projector firing 16:9 you are only employing 75% of your 16:12 available phosphor. With 2.35, you are down to 56%. So to be able to use all the available phosphor And two projectors, three times the light output of one projector is enjoyed.

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[incova]

So if I wanted two 9500 PJs and a screen that is 300cm wide what size room would that require in terms of depth?

Basically is a room thats 5 metres by 4 metres large enough in terms of depth for this?

[Tim in Phoenix]

Okay

A 9500 with room to access the rear, lets say the projector is 48" front to back (122 cm) so if your 5 metres is the available room length, you have 378 cm from lenses to screen. This could work with ceiling mounted projectors. Presuming a 20% blend overlap, worst case a 1.0 throw ratio, your room would support a 378 cm screen width. If 4 metres is the long dimension, 278 cm screen width. Maybe a smidge more.

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[incova]

Thanks so much Tim.

[AnalogRocks]

[AnalogRocks]

[incova]

They do, I cant stand them lol, you should see what the british admiralty used to use................