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Barrykensett
12-26-2009, 10:22 AM
I think the aspiration of most sim builders up to now has been the use of three projectors for visuals which give a reasonable field of view and technically is fairly straightforward. There are however in my experience a few fundamental snags. One is the space required, projection distances are quite large (the newer short throw help but have edge definition shortcomings); one needs height and distance to project over the overhead panel or a long distance behind the screen for back projection (my current setup).Mirrors are possible but complicate things somewhat. There is also a sharpness problem even using XGA projectors because of the closeness of the eye to the screen. Higher resolution projectors are coming down in price but the pixels can still be seen. Projectors tend to be expensive to run over time.
Many sim builders have to work in small rooms where projection is difficult and they often use monitor screens which tend to be a bit small for the field of view required. Large monitors have been prohibitively expensive until recently.
I have been watching the prices of large TV screens for a couple of years now and I always thought that when the price of a 42" screen dropped to £400 that a serious review is necessary; that point has arrived noting the post Christmas sale prices in the UK. I chose 42" to watch as this is the size of the windscreen panel on my A320.
I have been looking at TV's rather than Monitors as they tend be be typically half the price,probably because of the higher numbers in the consumer market.
There are a number of issues however to consider and I thought it would be useful to share these thoughts.

1. Looking at a number of screens in the local shops I concluded that HD resolution will be needed, again this results from the closeness of the eye to the screen. In the home one would watch a 42" Tv from at least 10 feet away but when one is only three feet away the ghosting is intrusive. Looking at HD however is stunning sharpness for our purpose, so we are talking about a resolution of 1920 x 1080 (1080p standard) which most TV's now meet.

2. Looking at the Specs of the Triple Head to Go adaptor these can drive two screens at 1920 x 1080 so on the surface OK but I am not sure whether these are completely compatible; I do not yet know even what connectors one would use as the TV has HDMI and the Matrox is DVI.
3. Most reasonably good video cards have HDMI outputs so perhaps TH2G is not the way to go.

4. I am not sure that two screens will be the optimum. The junction of the screens will be down the centre pillar so not obtrusive, however there would not be a central forward view so the centreline of the runway will disappear when one is on track. It is not possible of course to move the head to look round the pillar. Perhaps we should really be thinking about three screens. These could then be positioned a bit further away and the runway centreline would be visible. it would also to possible to move the head to look round the pillar. If one's compromises allow the windscreen pillar to be removed the view would be more like a three panel windscreen aircraft; not authentic but could look quite good. If one accepts three screen then how to drive them? TH2G will handle three screens at 1680 x 1050 but I am not sure that this would be sharp enough.

5. Not sure what will happen to frame rates, presumably no worse than using three projectors.
Has anyone anything to share on this topic?
Barry
www.a320sim.com (http://www.a320sim.com)

Mike.Powell
12-26-2009, 12:21 PM
I agree. The falling cost of TVs creates a "sweet spot" on the cost-performance spectrum that will be hard to beat for the space constrained sim. Multiple projectors, warping and edge blending software, and a curved screen located farther from the eye point can hit a higher performance level, but only with a price premium.

Swiss1673
12-26-2009, 01:57 PM
2. Looking at the Specs of the Triple Head to Go adaptor these can drive two screens at 1920 x 1080 so on the surface OK but I am not sure whether these are completely compatible; I do not yet know even what connectors one would use as the TV has HDMI and the Matrox is DVI.
3. Most reasonably good video cards have HDMI outputs so perhaps TH2G is not the way to go.


It's allways digital... lot of connectors on the market and this will not be the problem.

Daniel

Nick1150
02-26-2010, 10:17 AM
Hi,

Thanks for sharing your thoughts :)

In fact, since I am in the process of researching the market to start my 737 ng sim, I have thought of purchasing 3 TVs instead of 3 projectors, mainly because of the space and complexity required. On the other hand one can say that the main advantage of projectors is the feeling of a wide extrernal visual result, without the, I must admit, annoying plastic boxes of a TV.

I now use one pc with two TH2GO and total six screens. I don't see why a TH2GO could not handle 3 TVs of what ever size, as long as fits within TH2GO resolutions limits.

Nevertheless, I could be wrong, but I am extremely curious to know if for example one could use one TH2GO with 3 42"TVs for external view.

Barrykensett
02-26-2010, 11:12 AM
Well I think that we all have to wait and see who blinks first to spend the money on three TV's and tell us if it is any good!
I notice now that 50" plasma screens seem to have plummetted in price.
Barry
www.a320sim.com

Nick1150
02-26-2010, 12:17 PM
Yeap ;)

The other days, I went to a mega store and saw a 50" Philips plasma 100Hertz with VGA IN and 1920 x 1080 resolution with 699 euros !!! Of course that is where I live (Greece).

twisted8
02-26-2010, 12:56 PM
I would like to see this too! I don't see why it wouldn't work. I have succesfully connected my pc to a 42" plasma TV, so 3 shouldn't be be much different.
I wonder if it's dangerous at all to sit so close to 3 hugle plasmas? hehehe, must produce a lot of heat too!

Neil Hewitt
02-26-2010, 01:56 PM
My project (on hold for a while, sadly) will use a 46" LCD TV as a primary display, and I'm considering a pair of matched TVs somewhere between 26" and 32" for side views; 3 x 46" would be just too big for my available space. My project is a generic pit so I'm not constrained on window size / shape and can build them to fit around the displays I choose, though exactly where and how to mount the displays for best effect is still something I'm thinking about.

You shouldn't have any problems connecting a modern PC + video card to any reasonably recent LCD / Plasma TV with an HDMI input, because all current video cards support the HDTV resolutions natively. HDMI is electrically identical to DVI + some extra lines for sound, so a DVI-HDMI adapter is all you need. I ran the display mentioned above from a Media Center PC at 1920x1080 without any issues, and indeed I'm now running a Full HD projector the same way (DVI -> HDMI) at 1920 x 1080 from the same PC. If it's got HDMI, it'll just work.

If you're debating over LCD vs plasma I'd strongly recommend LCD unless your enclosure is very sturdy and you're confident of your engineering skills. Plasma TVs are very heavy compared to LCDs of the same size, and while the picture is a little more lively and blacks tend to be deeper, good modern LCDs have a fantastic picture and would be ideal for a simpit, I think. Guess I'll find out in a few months when mine go in :)

NH