Rear Projection TV vs Front Projection

I recently moved, and as part of the move, I decided to switch from a front projection home theater to a traditional rear projection TV. There is some good information on the net about this.


Here's some notes based on my experience with these things.


Among the drawbacks of a projector:

  • They take time to warm up. Want to flip on the news to see what's happening? It's going to take you a lot longer with a projector, since it's got to warm up. My Plus U3-880 would take nearly a minute before I could start watching it; the new TV takes just a few seconds.

  • They have a fan.. the one in my projector is annoyingly loud.

  • Room lighting is a concern. Even with a bright projector (2000 lumens is a bright projector for a medium size room), it's going to look better in the dark.

  • Bulb life. My projector was terrible for this - 1000 hours, from about a $500 (Cdn$) bulb. This meant it was costing me $1 in bulb life to watch a movie, and it ruled out leaving the TV on in the background while doing something else.

But projectors are awesome. If you don't mind these drawbacks (get a bright, quiet projector and don't mind the startup time) then you'll get a picture that's probably 4x the size of a rear projection set, for less money (depending on how much you spend on a screen - or you can do what I did and paint the wall a matte white - with the right paint it looks as good as some screens).


The biggest drawback of a rear projection set for me is the lack of a non-interlaced mode. An interlaced picture is a picture where instead of refreshing the whole screen 60 times a second, half the screen (every second line) is refreshed 60 times a second, so it takes two frames to draw a complete image.


HDTV defines a number of different formats - traditional television is analog, so they measure scanlines rather than 'resolution' - 480i is 480 lines interlaced; 480p is 480 lines progressive. Progressive is TV talk for 'not interlaced'. 720p is 720 lines non-interlaced, and 1080i is 1080 lines interlaced.  Interlace works fine for television, but when you're playing video games or using a computer (where you typically have sharp horizontal lines), the flicker of those lines is noticeable.


So ideally, if you're playing video games or using a computer on your big screen, having 720p would be the way to go. With the standard HDTV aspect ratio of 16:9, 720 lines means the horizontal resolution is 1280. A 1280x720 desktop on your big screen TV would look pretty nice, and ATI has video cards that you can plug right in. With a computer monitor, there's usually the concept of syncing to multiple frequencies. NEC started this back with their MultiSync monitor, and now they all do it. When your PC is booting up, you can usually tell when your computer switches from the boot resolution (probably 640x480) into the resolution your desktop is configured for, as your monitor will visibly readjust itself.. Rear projection TV's don't do this. I don't know why, but as far as I can tell, they all sync only to 1080i - They're all interlaced.  If they receive a 480p signal or a 720p signal, they upconvert it to 1080i. So they'll take your non-flickering desktop image and make it flicker. Doh.


(Side note: The Amiga let you choose between 640x200 non-interlaced and 640x400 interlaced for your desktop.. and I believe most users used 640x200, trading off doubling their desktop space for not having it flicker. You could buy FlickerFixer type devices that tried to dull the flicker, but in general it's not something you want to be using for a long time).


Interestingly enough, the other common TV technologies like Plasma, LCD, and DLP sets, have a native resolution of 720p. If you feed them a 1080i signal , they convert it to a non-flickering 720p signal. Unfortunately these devices are usually more tham double the price of a CRT-based RPTV. But, all the 'data' projectors I've seen will do the same thing - projecting a non-interlaced signal for whatever input you feed them. This makes a projector a better device for hooking up to an XBox or to a computer.


But, I went with a rear projection CRT-based set (the Toshiba 57HX84). I could have gotten a projector for the same price, but the reasons I went with the Toshiba are the startup time and bulb life. Plop down on the couch, hit the power button on the remote, and the TV is on. And I can leave it on for 4 hours while I'm working on my laptop without worrying about bulb life.


I haven't hooked my PC up to my Toshiba 57HX84 TV yet; I'll let you know how it looks once I do.