18 Feb 2008 04:38:05 | Andrew Ghigo
One of the big questions every home theater enthusiast has to
face when planning a new home theater is whether to invest in a
rear projection TV, or to opt for the two piece video projector
- screen setup.
Both approaches have got their pros and cons. In this article,
we discuss the advantageous and limitations of rear projection
systems as a big screen solution in the home theater.
Rear Projection Television - An Affordable Option
A great deal of consumer appeal for Rear Projection TV systems
arise out of the shear simplicity that this product offers as an
immediate solution to getting a bigger TV.
No mess, no fuss, if you have the space, either visit your
local big screen retailer - or better still, check at your
favorite online electronics superstore - to order your product
and get it delivered in just a few days; unpack the product and
there you have a big screen TV in your living room ready for
immediate use!
Rear Projection TV Facts:
As already stated, rear projection offers a most immediate
solution to getting a bigger TV. Probably, this is also one of
the main drivers behind rear projection television sales.
Yet the real 'culprit' behind the popularity of rear projection
TV systems does not arise out of some particular benefit
associated with rear projection, but out of the fact that most
big screen retailers seem to give the impression that rear
projection systems are cheaper than a front projection setup.
This may be true in retail stores, but not necessary so when
buying online. The reality is that for a given budget level,
prices online are such that front projectors will deliver a much
more cinema-like experience for the same price bracket.
Therefore, do not base your decision on price alone to decide
between a front projection setup and a rear projection TV box.
Clearly, there is a market for both - the primary decisive
factor should be your room size. If you don't have a large
viewing room, a 40" to 60" diagonal TV will probably be more
than adequate rendering a rear projection TV the ideal
affordable solution - as long as it fits in the available space.
Size - or rather unit depth - is becoming less of a
problem with modern LCD and DLP rear projection TV units. A
typical 52” diagonal widescreen DLP or LCD rear projection TV
set requires no more than 15-inches in depth; this contrasts
heavily with a similar size CRT rear projection model which
would normally require between 22 and 24 inches in depth.
What's more, considering that a similar size Plasma TV is still
out of reach of most average household budgets, today's
slim-styled LCD and DLP rear projection TV sets, with their
lower prices yet high performance, are becoming the affordable
'immediate' big screen TV option in the television mass-market.
However prior to committing yourself to a rear projection
TV, it is important to be fully aware of a few limitations
associated with rear projection systems, namely: limited screen
size, limited viewing angle, glare problems, poor aspect ratio
management, poor use of floor-space, etc.
We take a look at each of these limitations in further detail
below:
Screen size: Rear projection TV systems come in screen
sizes ranging from typical 42" up to a maximum of just over 70".
This may or may not be a limitation. It is true that you can get
a 100" projection with a home theater projector for the price of
a high quality digital 50" rear projection TV, yet the screen
size should be dimensioned to suit your room. If your room size
does not support such big projections, rear projection is
probably the way to go.
Viewing angles: Rear projection TV systems used to have
a rather limited viewing angle - with the optimum viewing
position being one directly in front of and eye-level with the
unit. Move away to either side, and color, contrast, and
brightness will degrade substantially. A narrow viewing angle
will limit the number of people who can watch the set due the
lowering in picture quality at the extreme viewing angles. Most
modern systems support a viewing angle of circa 150 degrees -
which should be adequate for normal home theater use. However,
it is always best to check on this prior to your purchase as
some products are worse than others.
Reflections: It is common that any light source at a
complementary angle to your viewing-angle will result in glare -
in particular if the unit makes use of a screen-saver (a clear
protective material that covers the fragile screen itself).
Glare can seriously degrade the picture quality. The only real
solution is to take away the offending light source; in some
cases the situation can improve if one removes the screen-saver
– BUT remember that an unprotected screen is fragile and
expensive to replace if damaged.
Floor-space: Any rear projection TV is literally a large
box with a relatively large footprint. It is true that modern
slim-type models do exist that are no more than 15 to 18 inches
in depth - depending on the screen size, yet the cheaper
CRT-based rear projection TV sets will stand out by at least 24
to even 30 inches to allow for the necessary air-space between
the back of the unit and the wall.
Remember to take this into your calculations when
planning your home theater as these two feet or so will have to
be deducted from your available viewing
distance.
Rear Projection TV Speakers: Forget all about them! Do
not give any weighting to the speaker system coming with your
rear projection unit. You would not be using them as you will
surely want to replace these with your dedicated home theater
surround receiver speaker system. Do not even think of using the
build-in speakers of your rear television set as a center
channel replacement. They will just interfere with the sound
coming out of your dedicated system - hence do not pay anything
extra for this as you will surely be switching off your TV sound
completely during a movie show.
Aspect ratios: We have already mentioned a number of
limitations associated with rear projection television, yet in
comparison, these are just minor issues. The real serious
limitation with a rear projection TV is aspect ratio
management.
This is the trickiest of it all. Standard television comes only
in 4:3 but rear projection TV systems come in both standard 4:3,
and in the 16:9 widescreen format. Once you choose your format
however, you have to live with it - so once again, you have to
choose wisely.
The 4:3 (1.33) or 16:9 (1.78) referred to as the aspect ratio,
is the ratio of the screen width with respect to the height of
the image. All standard non-HDTV material is in the 4:3 format
while most modern films come in one of the many widescreen
formats - the most common being the 2.35, which in itself is not
compatible with any of the fixed aspect ratio TV systems.
There are various ways to deal with this -
including: Image stretching to fill the
available screen. Use of black or gray bars on top
and bottom of a 4:3 screen to show the movie in its correct
aspect ratio as originally filmed, but then the effective film
display will be smaller. Pan and scan editing where
only the most important portion of each frame is shown with the
rest being discarded.
Image stretching and horizontal bars can be
extremely irritating while in the 'pan and scan' you are
giving up film information to have a full screen view. Worst of
all, prolonged use of horizontal bars - especially black bars -
leads to tube burn-out in CRT based systems at huge costs to you.
The incompatibility between screen formats renders the decision
on aspect ratio a rather complicated issue when choosing a rear
projection TV set. Surely, there is no such dilemma with a front
projection setup, but if your only way forward is rear
projection, then you will have to choose wisely.
Here no one can help you in your decision - it is simply a
matter of preference. The best way to decide on aspect ratio is
by first determining what you will be viewing most.
Making the Choice:
Surely, there is a market for both front and rear projection
TVs – it is all a question of knowing what are the advantages
and limitations of each with respect to your specific needs.
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reserved.
About Author :
Andrew Ghigo – editor & publisher of http://www.pra
ctical-home-theater-guide.com - a comprehensive home theater
guide to home theater systems, product reviews and home theater
design.