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CTR:
Keep in mind three things about any CRT projector system (front or RPTV):
Brightness can be an issue: This isn’t a major problem for RPTVs, where
the tube is relatively close to the screen, but in a front projector environment,
the CRT is the least bright of all the alternatives. Imagine trying
to light up a screen across the room with your old direct-view TV (not
really a fair comparison, but the technology is very similar), and you’ll
understand that a CRT doesn’t throw off a ton of light. The other systems
we discuss use a separate (high-powered) light source, which gives
them greater brightness. So a CRT front projector works best in a room
208 Part III:Watching and Listening: Display and Control Devices
with very little ambient light; in fact, near total darkness works best.
(Total darkness gives you the best picture with any front-projection
system.)
Tubes wear out: Just as direct-view CRTs lose brightness over time, so
do CRT projectors. In fact, because CRT projectors need to be set up to
project more light than a direct-view TV (especially front projectors),
CRT tubes in a projector tend to wear out even faster. Check the manufacturer’s
specifications for how quickly its tubes lose brightness and
plan on budgeting some home theater money for new tubes based on
those specifications. This isn’t a cheap fix. You can spend thousands of
dollars on new tubes every time you need to replace them, so read the
fine print.
Tubes can get burn-in: Burn-in occurs when static content, such as
video games, permanently alters the phosphors on your CRT, so that
you always see, for example, a ghost image of Halo’s weapons status on
your screen. If you (or your kids) play a ton of video games, we suggest
you look at one of the other projector technologies we’re about to discuss.
Burn-in can also be a problem when the CRTs have a fixed aspect
ratio. For example, if you have 16:9 (widescreen) tubes and watch a ton
of 4:3 (traditional square screen) content, you can end up with uneven
brightness on the tubes. This occurs because the center of the tube is
constantly in use, but the edges are used only occasionally. (We discuss
burn-in earlier in this chapter.)
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