 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
How to Select
a Home Theater Projector
a Home Theater Projector
What Makes a Good Home Theater Projector?
There a several things that make a projector good for home theater applications as
opposed to presentation duties. Many projectors on the market are either business
presentation projectors or adapted from them. Presentation projectors are optimized
for Powerpoint and other business presentations.
In the presentation environment brightness is king. It is important for the material to
be brightly lit to enable easy viewing in a lit room. It is not so important that the colors
are perfect. After all, who really knows what color red is supposed to be on that pie
chart anyway? Grey scale tracking is not relevant either as long as it meets some
arbitrary minimum standard. Likewise, the black level is not all that important and is
usually sacrificed to achieve better brightness.
The reproduction of full motion video for a presentation type projector does not need
to meet the same standard that a home theater projector must meet. If there are
some motion artifacts present it really doesn't matter to a great extent. Eliminating the
artifacts would have raised the price of the projector, angering corporate purchasing
managers and reducing the number of units they could fit in the annual budget.
Home theater projectors on the other hand stress the very performance parameters
the business presentation units don't. In most home theaters there is good light
control. Most digital projectors have ample brightness for normal screen sizes. Black
level and low level detail however, is extremely important to reproducing film like
images.
Color rendition is also critical. Going hand-in-hand with accurate color rendition is
accurate grey scale tracking. Inaccurate grey scale tracking will cause the shade of
grey to be biased too far toward one of the primary colors. It can also change with
brightness, being for example, too far towards blue in the bright areas of the picture
and too green in the darker areas. The color information is laid over the black and
white, called the luminance, information. That is why accurate grey scale tracking is
so important for a good home theater projector, or any other video display for that
matter.
Projector Types
Analog Projectors
CRT
Advantages –
• Excellent black level
• Great color palette
• Smooth image with no pixel structure
• The most film-like of all current projection technologies
Disadvantages –
• Low light output
• Much more difficult to set up correctly than any digital projector
• Requires regular maintenance for continued, good picture quality
• Heavy and large physical size
CRT projectors are almost extinct, but don't sell them short. When properly set up,
they can provide a rich, film like image that has virtually no equal. This is especially
true if you are using a small screen, under 100" diagonal or so, and good image
processing. Luckily, image processors and scalers have become very cost effective in
the last few years. Old timers probably remember when the Faroudja LD-100 was
introduced at $15,000. Thankfully, you can now get great processing for about a
tenth of that sum. Most CRT projectors will not accept component video, so you'll
need a video transcoder to use component video sources. The transcoder will
convert the component video into RGB video that the projector will accept. Most
projectors with 9" CRTs will deliver dramatic 1080p resolution for HD-DVD, BRD or
deinterlaced HDTV.
How they work: A CRT projector uses Cathode Ray Tubes to create the projected
video image. CRT is the same technology used in a traditional TV set, although
slightly different in implementation. This is a very mature technology that has been in
widespread use since just after WWII. CRT projectors use an electron gun inside a
large vacuum tube to accelerate and shoot a beam of electrons into a phosphor
material. When hit by the beam, the phosphor glows with brightness proportional to
the beam strength.
This is where a CRT projector derives one of its primary strengths; its ability to
provide deep blacks and an almost infinite color gradiation. It is able to produce such
deep blacks because to produce black, a CRT just shuts off the electron beam,
producing no light. With digital projectors, the light is produced by a light source all
the time.
CRT projectors are available in 7", 8" and 9" tube size, with the larger tubes being
better. The 9" CRT projectors will have better light output and resolution. There are
two main types of systems used to focus the electron beam into a small spot on the
tube face; electrostatic focus and electromagnetic focus. Electromagnetic focus
provides better beam spot control and is usually found on the better 8" and 9" CRT
projectors.
Digital Projectors
- Digital projectors use a light source, typically a lamp, to make their light. To produce
blacks, this light must be redirected or interrupted. Even with the best systems, a
small fraction of the light makes it to the screen so the black levels of the digital
projectors are not yet to the level of good CRT units, although recent developments
have closed the gap considerably. A disadvantage of all digital projectors is the
requirement for periodic bulb replacement. Bulbs typically last from 1,000 - 4,000
hours and cost from $250 - $700. Keep this recurring expense in mind when
choosing a home theater projector.
It's a good idea to get an extra bulb if you plan on using your projector alot. This will
avoid the loss of a bulb right before a big weekend, such as the Superbowl or Final
Four. You just can't run down to the Home Depot and pick one up. There are two
primary bulb types used for digital projectors, Xenon and UHP (Ultra High Pressure).
The Xenon bulbs require less filtering to achieve perfect color balance, but are more
expensive. Some newer rear projection digital projection systems use high brightness
LEDs as a light source. LEDs have an extremely long lifespan, effectively eliminating
the necessity of changing them.
DLP Projectors
DLP™ (Digital Light Processing) is an imaging technology developed by Texas
Instruments. According to Pacific Media Associates (PMA), DLP technology began
2006 with 58% of worldwide market share in front projectors. The DLP™ system uses
a chip covered with thousands of extremely tiny mirrors to direct light. The light goes
either through the lens to make an image or into a light trap depending on weather or
not the particular pixel should be on or off.
There are two main distinctions between DLP projectors. They are either single or
three chip designs. As the name implies, a single chip DLP projector uses one DLP
chip. The image goes through a rapidly spinning color wheel. The color wheel is
segmented into red, green and blue sections. Newer wheels on home theater
projectors have 7 or 8 segments, with a dark segment being used to create deeper
blacks. The color wheel filters the light into red, green or blue, depending upon which
of its segments is in front of the lamp. The projector creates a full color image by
rapidly projecting red, green and blue images in sequence. The viewers mind blends
them together into a full color image.
A three chip DLP projector avoids the color wheel by using a DLP chip for each color.
By avoiding the color wheel and sequential display, the image is not subject to an
image anomaly known as "rainbows", that was prevalent among early single chip
designs, but is much reduced today. Three chip DLP projectors have an extremely
stable image but are much more expensive than single chip designs due to the added
complexity. A three chip DLP projector separates the light from the projector into red,
green and blue components then sends each color through a different DLP
assembly. After the image is greated for each color, the red, green and blue images
are recombined to form a full color image.
There are several different chips currently being used, and others have been used
since the introduction of DLP technology. TI introduces new chipsets fairly regularly.
In April, 2005, TI's DLP™ Products announces that its 1920 x 1080 high-definition
(HD) resolution DLP™ TV technology was being shipped to customers. This DLP chip
will allow 1080p displays for the latest in high definition. Texas Instruments showed
their latest 1080p DLP chips they call DarkChip 4 at the 2007 CEDIA expo in Denver.
Advantages
• Can be very bright
• Good black levels, although not yet to the level of a CRT projector
• Small size, light weight (some 3-chip DLP designs can be much larger and
heavier than a single chip unit)
Disadvantages-
• Single chip models can have video artifacts known as “rainbows”. This artifact
has been dramatically reduced with the new high speed, 7 & 8 segment color wheels.
• Some units have very loud fan noise, but most of the newer DLP projectors are
very quiet, especially the units designed especially for home theater use. Brighter
single chip and 3-chip models tend to make more noise.
LCD Projectors
LCD projectors were the first widely used digital projectors and are still very popular
today. The LCD projectors available today are orders of magnitude better than the
units available in the past. At the 2006 CEDIA Expo, Mitsubishi introduced an LCD
projector, using 3 of the latest inorganic LCD panels, with full 1920 x 1080 resolution,
for well under $5,000! In an LCD projector the image is created by using an array of
liquid crystals to control the light from a light source. It is the same basic technology
used for laptop computer displays, cell phone displays and calculators. Liquid crystals
are either straight, allowing light to pass, or twisted, blocking light. These liquid
crystals are arranged into arrays on panels. The LCD panels usually have one of the
following resolutions:
LCD projectors usually have three LCD panels, one each for red, green and blue.
The white light from the bulb is passed through a series of dichroic lenses that
separate the white light into red, green and blue. Each color then passes through an
LCD panel. That panel is responsible for controlling the pixels on the screen that are
required to be the corresponding color for each frame of video.
LCOS (Liquid Crystal on Silicon) Projectors
LCOS projectors have two main consumer producers, Sony and JVC. Sony's LCOS
variant is known as SXRD and JVC's, D-ILA or HD-ILA. Liquid Crystal on Silicon
(LCOS) displays are a reflective technology as is DLP. However, there are some
important differences. With DLP each pixel is created using a transistor controlled
mirror. With LCOS, a reflective substrate is controlled by the liquid crystal. As the
liquid crystals either open or close, the light for that specific pixel is reflected through
the lens and onto the screen.
LCOS displays are usually three chip designs, bringing the same advantages that
come with a three chip DLP design; they require no color wheel, and thus have none
of the associated video artifacts.
There a several things that make a projector good for home theater applications as
opposed to presentation duties. Many projectors on the market are either business
presentation projectors or adapted from them. Presentation projectors are optimized
for Powerpoint and other business presentations.
In the presentation environment brightness is king. It is important for the material to
be brightly lit to enable easy viewing in a lit room. It is not so important that the colors
are perfect. After all, who really knows what color red is supposed to be on that pie
chart anyway? Grey scale tracking is not relevant either as long as it meets some
arbitrary minimum standard. Likewise, the black level is not all that important and is
usually sacrificed to achieve better brightness.
The reproduction of full motion video for a presentation type projector does not need
to meet the same standard that a home theater projector must meet. If there are
some motion artifacts present it really doesn't matter to a great extent. Eliminating the
artifacts would have raised the price of the projector, angering corporate purchasing
managers and reducing the number of units they could fit in the annual budget.
Home theater projectors on the other hand stress the very performance parameters
the business presentation units don't. In most home theaters there is good light
control. Most digital projectors have ample brightness for normal screen sizes. Black
level and low level detail however, is extremely important to reproducing film like
images.
Color rendition is also critical. Going hand-in-hand with accurate color rendition is
accurate grey scale tracking. Inaccurate grey scale tracking will cause the shade of
grey to be biased too far toward one of the primary colors. It can also change with
brightness, being for example, too far towards blue in the bright areas of the picture
and too green in the darker areas. The color information is laid over the black and
white, called the luminance, information. That is why accurate grey scale tracking is
so important for a good home theater projector, or any other video display for that
matter.
Projector Types
Analog Projectors
CRT
Advantages –
• Excellent black level
• Great color palette
• Smooth image with no pixel structure
• The most film-like of all current projection technologies
Disadvantages –
• Low light output
• Much more difficult to set up correctly than any digital projector
• Requires regular maintenance for continued, good picture quality
• Heavy and large physical size
CRT projectors are almost extinct, but don't sell them short. When properly set up,
they can provide a rich, film like image that has virtually no equal. This is especially
true if you are using a small screen, under 100" diagonal or so, and good image
processing. Luckily, image processors and scalers have become very cost effective in
the last few years. Old timers probably remember when the Faroudja LD-100 was
introduced at $15,000. Thankfully, you can now get great processing for about a
tenth of that sum. Most CRT projectors will not accept component video, so you'll
need a video transcoder to use component video sources. The transcoder will
convert the component video into RGB video that the projector will accept. Most
projectors with 9" CRTs will deliver dramatic 1080p resolution for HD-DVD, BRD or
deinterlaced HDTV.
How they work: A CRT projector uses Cathode Ray Tubes to create the projected
video image. CRT is the same technology used in a traditional TV set, although
slightly different in implementation. This is a very mature technology that has been in
widespread use since just after WWII. CRT projectors use an electron gun inside a
large vacuum tube to accelerate and shoot a beam of electrons into a phosphor
material. When hit by the beam, the phosphor glows with brightness proportional to
the beam strength.
This is where a CRT projector derives one of its primary strengths; its ability to
provide deep blacks and an almost infinite color gradiation. It is able to produce such
deep blacks because to produce black, a CRT just shuts off the electron beam,
producing no light. With digital projectors, the light is produced by a light source all
the time.
CRT projectors are available in 7", 8" and 9" tube size, with the larger tubes being
better. The 9" CRT projectors will have better light output and resolution. There are
two main types of systems used to focus the electron beam into a small spot on the
tube face; electrostatic focus and electromagnetic focus. Electromagnetic focus
provides better beam spot control and is usually found on the better 8" and 9" CRT
projectors.
Digital Projectors
- Digital projectors use a light source, typically a lamp, to make their light. To produce
blacks, this light must be redirected or interrupted. Even with the best systems, a
small fraction of the light makes it to the screen so the black levels of the digital
projectors are not yet to the level of good CRT units, although recent developments
have closed the gap considerably. A disadvantage of all digital projectors is the
requirement for periodic bulb replacement. Bulbs typically last from 1,000 - 4,000
hours and cost from $250 - $700. Keep this recurring expense in mind when
choosing a home theater projector.
It's a good idea to get an extra bulb if you plan on using your projector alot. This will
avoid the loss of a bulb right before a big weekend, such as the Superbowl or Final
Four. You just can't run down to the Home Depot and pick one up. There are two
primary bulb types used for digital projectors, Xenon and UHP (Ultra High Pressure).
The Xenon bulbs require less filtering to achieve perfect color balance, but are more
expensive. Some newer rear projection digital projection systems use high brightness
LEDs as a light source. LEDs have an extremely long lifespan, effectively eliminating
the necessity of changing them.
DLP Projectors
DLP™ (Digital Light Processing) is an imaging technology developed by Texas
Instruments. According to Pacific Media Associates (PMA), DLP technology began
2006 with 58% of worldwide market share in front projectors. The DLP™ system uses
a chip covered with thousands of extremely tiny mirrors to direct light. The light goes
either through the lens to make an image or into a light trap depending on weather or
not the particular pixel should be on or off.
There are two main distinctions between DLP projectors. They are either single or
three chip designs. As the name implies, a single chip DLP projector uses one DLP
chip. The image goes through a rapidly spinning color wheel. The color wheel is
segmented into red, green and blue sections. Newer wheels on home theater
projectors have 7 or 8 segments, with a dark segment being used to create deeper
blacks. The color wheel filters the light into red, green or blue, depending upon which
of its segments is in front of the lamp. The projector creates a full color image by
rapidly projecting red, green and blue images in sequence. The viewers mind blends
them together into a full color image.
A three chip DLP projector avoids the color wheel by using a DLP chip for each color.
By avoiding the color wheel and sequential display, the image is not subject to an
image anomaly known as "rainbows", that was prevalent among early single chip
designs, but is much reduced today. Three chip DLP projectors have an extremely
stable image but are much more expensive than single chip designs due to the added
complexity. A three chip DLP projector separates the light from the projector into red,
green and blue components then sends each color through a different DLP
assembly. After the image is greated for each color, the red, green and blue images
are recombined to form a full color image.
There are several different chips currently being used, and others have been used
since the introduction of DLP technology. TI introduces new chipsets fairly regularly.
In April, 2005, TI's DLP™ Products announces that its 1920 x 1080 high-definition
(HD) resolution DLP™ TV technology was being shipped to customers. This DLP chip
will allow 1080p displays for the latest in high definition. Texas Instruments showed
their latest 1080p DLP chips they call DarkChip 4 at the 2007 CEDIA expo in Denver.
Advantages
• Can be very bright
• Good black levels, although not yet to the level of a CRT projector
• Small size, light weight (some 3-chip DLP designs can be much larger and
heavier than a single chip unit)
Disadvantages-
• Single chip models can have video artifacts known as “rainbows”. This artifact
has been dramatically reduced with the new high speed, 7 & 8 segment color wheels.
• Some units have very loud fan noise, but most of the newer DLP projectors are
very quiet, especially the units designed especially for home theater use. Brighter
single chip and 3-chip models tend to make more noise.
LCD Projectors
LCD projectors were the first widely used digital projectors and are still very popular
today. The LCD projectors available today are orders of magnitude better than the
units available in the past. At the 2006 CEDIA Expo, Mitsubishi introduced an LCD
projector, using 3 of the latest inorganic LCD panels, with full 1920 x 1080 resolution,
for well under $5,000! In an LCD projector the image is created by using an array of
liquid crystals to control the light from a light source. It is the same basic technology
used for laptop computer displays, cell phone displays and calculators. Liquid crystals
are either straight, allowing light to pass, or twisted, blocking light. These liquid
crystals are arranged into arrays on panels. The LCD panels usually have one of the
following resolutions:
- 4 x 3 aspect ratio - 800 wide x 600 high, 1024 x 768, 1280 x 1024, 1200 x 1600
- 16 x 9 aspect ratio - 1280 x 720, 1920 x 1080
LCD projectors usually have three LCD panels, one each for red, green and blue.
The white light from the bulb is passed through a series of dichroic lenses that
separate the white light into red, green and blue. Each color then passes through an
LCD panel. That panel is responsible for controlling the pixels on the screen that are
required to be the corresponding color for each frame of video.
LCOS (Liquid Crystal on Silicon) Projectors
LCOS projectors have two main consumer producers, Sony and JVC. Sony's LCOS
variant is known as SXRD and JVC's, D-ILA or HD-ILA. Liquid Crystal on Silicon
(LCOS) displays are a reflective technology as is DLP. However, there are some
important differences. With DLP each pixel is created using a transistor controlled
mirror. With LCOS, a reflective substrate is controlled by the liquid crystal. As the
liquid crystals either open or close, the light for that specific pixel is reflected through
the lens and onto the screen.
LCOS displays are usually three chip designs, bringing the same advantages that
come with a three chip DLP design; they require no color wheel, and thus have none
of the associated video artifacts.
Home Theater Projector Calibration DVDs
Make sure you get all you home theater projector has to offer. If you are not going to
have a complete ISF calibration done, you should at least do a basic calibration it to
make sure your image has the correct color, black and white level settings. The
importance of proper projector calibration cannot be understated. The picture will be
much improved and you'll be able to enjoy your movies in all their splendor, just as
the director intended.
We've used both of these DVDs and they both work very well, with all of the test
patterns and instructions necessary to let you get the most from your video display.
Don't worry if you've never done something like this before, the instructions are easy
to follow and the entire basic projector calibration procedure usually only takes 10 -
20 minutes.
Make sure you get all you home theater projector has to offer. If you are not going to
have a complete ISF calibration done, you should at least do a basic calibration it to
make sure your image has the correct color, black and white level settings. The
importance of proper projector calibration cannot be understated. The picture will be
much improved and you'll be able to enjoy your movies in all their splendor, just as
the director intended.
We've used both of these DVDs and they both work very well, with all of the test
patterns and instructions necessary to let you get the most from your video display.
Don't worry if you've never done something like this before, the instructions are easy
to follow and the entire basic projector calibration procedure usually only takes 10 -
20 minutes.
Copyright 2004-7 1touchmovie.com
Home theater and Automation Guide
All rights reserved.
Home theater and Automation Guide
All rights reserved.
Home Theater Projector Information
1 Touch Movie.com
Home Theater
Programming Sources
Programming Sources
Off-Air TV
| We will not sell, rent or lease your information to others. |
| Sign Up Now for our FREE Home Theater & Automation Newsletter for great insider home theater info, tips and ideas & get a FREE copy of the 72p Home Theater Design eBook. Be sure and check your email for the confirmation link. |