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TYPES OF VIDEO DISPLAYS
Once you've decided on the best room, you can begin to figure out what you're
going to need to complete the home theater system of your dreams and where
you might place everything. You'll probably begin by thinking about the TV screen. That's natural. But you need to think about the speakers and electronics too. After all, a great picture and mediocre sound isn't what you really want, is it? First, decide which type of video will best answer your needs. There are several choices:
1. "Flat Panel" sets: These self-contained displays are the new "hot ticket" to home theater enjoyment. Some go as large as 71" (diagonally) and are thin enough to hang on a wall, a major cosmetic advantage. There are two major different types of flat panel TVs on the market today: LCD's and Plasma. It's not a war, it's a choice. Both flat panel TV's are thin, sleek, state-of-the-art, and capable of displaying stunning hi-def pictures with surprisingly wide viewing angles. Both have their advantages and disadvantages. Which is right for you? Let Audio Visions help you out.
2. "Rear projector" sets: These one-piece, large screen sets offer a good compromise if you are looking for a large TV and Front projection is not an option due to light. This technology is very attractive in terms of price and video processing. Newer rear projection TVs are significantly less affected by bright light or glare. The newest rear projector TV's are typically “DLP” sets. DLP is a patented technology from Texas Instruments that stands for Digital Light Processing. DLP technology has allowed rear projection TV's to become much “shallower” and lighter than the old models, while enhancing brightness, color presentation and general picture quality. This allows the TV to be placed much closer to the wall and frees up valuable floor space. These sets use “lamps” that have be to be replaced every few years, depending upon use. Recently the life span of an average DLP lamp has increased to 7000 hrs and higher. DLP rear projection can now be seen up to 73” diagonally.
3. "Front projector" sets: Many people consider these two-piece sets (projector and separate screen) as the ultimate in dramatic picture quality. Their main advantage? They can project a BIG image -- in some cases, more than 100" measured diagonally. Disadvantages? For best picture quality, they are best used in rooms with dim or controlled lighting. Many Front projectors also use DLP technology. Brightness, contrast and picture quality continue to improve dramatically as this technology evolves. There is a great variation in picture quality and cost between different projectors. The old saying, “you get what you pay for”, is very true when it comes to Front projectors. Remember, there is a big difference between inexpensive “business projectors” and true “home theater” projectors. Business projectors may be very bright, but are not designed for moving scenes or a true and accurate color presentation. Remember to pay attention to the screen you choose, too. There are numerous sizes, styles and fabric choices, based on lighting requirements, projector specifications and viewing distance. It will have a major impact on picture quality.
4. A "direct view" TV: This is the conventional television we're all used to. Many stores do not carry these any longer and they can be hard to find. Direct view sets usually produce a great picture, but only as good as their resolution dictates. They're also relatively immune to other light sources: They'll give you the same picture quality in a dim or brightly lighted room. Size may be a consideration. This is really considered “old technology” and probably best to steer away from these TV's.
WHAT YOU'LL SEE
Older TV's used a screen that was nearly square and have an "aspect ratio" (width compared to height) of 4:3 or "4 units wide by 3 units high." It is difficult to find a TV like this today.
The new "widescreen" displays, in contrast, are much wider than' they are high. Their aspect ratio is 16:9 and they resemble small movie screens - no accident there! Some higher end Front projectors offer a 2.35:1 aspect ratio. (the equivalent of 21:9 – even wider!).
In addition, you should understand something about resolution ; or the display's ability to reveal fine details. In most of North America , you used to be limited by broadcast and cable signals that adhere to the NTSC (National Television Systems Committee) analog standard. This means that TV pictures contained 480 visible SCAN LINES, each consisting of approximately 330 individual PIXELS or picture elements.
The arrival of “digital broadcasting” has ushered in the age of High Definition. The new generation digital television signals are available in most places in North America as a broadcast either directly from an off-air (antenna) source, cable or from a satellite system. Regardless of how you receive it, digital TV typically comes in three flavors - SDTV, EDTV, and HDTV.
SDTV, or standard definition television won't convey any more detail than NTSC signals but will be modestly better due primarily to the fact that its digital format is less prone to signal degradation and consequent corruption than NTSC's analog-based format. SDTV is best suited for smaller screen sizes.
EDTV ( enhanced definition TV) delivers visibly better pictures than NTSC: 480 visible scanning lines, each containing 640 pixels. The additional detail looks pretty good on a larger screen. (This is, incidentally, even better than DVD's potential. And we all know how good that is!) But, it still does not take full advantage of the capabilities of these new TV's.
HDTV ( high definition TV) will deliver a truly stunning picture with up to 1080 scanning lines, each with a potential of up to 1920 pixels! That's far better resolution than you'll find with either NTSC or lower-resolution digital TV sources. HDTV signals rival the quality of movie film when displayed properly. BLUE RAY and HD-DVD are the names of a next-generation optical disc format jointly developed two competing groups of the world's leading consumer electronics, personal computer and media manufacturers (The Blue-Ray consortium includes Apple, Dell, Hitachi, HP, JVC, LG, Mitsubishi, Panasonic, Pioneer, Philips, Samsung, Sharp, Sony, TDK and Thomson). (The HD-DVD consortium includes Toshiba and Microsoft). What we have is beginning of a new format war. Beta Max versus VHS anyone? These formats were developed to enable recording, rewriting and playback of high-definition video (HD), as well as storing large amounts of data. Both formats offer more than five times the storage capacity of traditional DVDs and can hold up 50GB on a dual-layer disc. This extra capacity combined with the use of advanced video and audio codecs will offer consumers an unprecedented HD experience.
While current optical disc technologies such as DVD, DVD±R, DVD±RW, and DVD-RAM rely on a red laser to read and write data, the new formats uses a blue -violet laser instead. Despite the different type of lasers used, Blu- ray or HD-DVD products can easily be made backwards compatible with CDs and DVDs through the use of a BD/DVD/CD compatible optical pickup unit. The benefit of using a blue -violet laser (405nm) is that it has a shorter wavelength than a red laser (650nm), which makes it possible to focus the laser spot with even greater precision. This allows data to be packed more tightly and stored in less space, so it's possible to fit more data on the disc even though it's the same size as a CD/DVD. This together with the change of numerical aperture to 0.85 is what enables these new formats to hold up to 50GB. The good news is that many Blue-Ray or HD-DVD players from both camps will play both formats. For the ultimate viewing experience on your new 1080p TV, this is the way to go!
WHEN IS "BIG" REALLY "BIG ENOUGH"?
There are no hard and fast rules governing the relationship between room size and screen size. Remember that bigger (screen size, that is) is not always better. The old guideline (for NTSC sources, of course) was that you should sit at a distance 10 times greater than the screen's height . For persons with "normal" eyesight, this was far enough away so that the scan lines were not visible. However, 'hi def" (high definition) video sources changed this. Hi def source and more - and usually far narrower scan lines than NTSC sources. This means you can sit closer to the screen and not see them. In addition, hi def's aspect ratio (16:9 as opposed to 4:3) makes screen width more important than height. With most hi def sources, you can sit just 3 times the screen width away and enjoy a fine picture.
Best of all, the cost of really large screen sizes, whether Rear projection, Font projection, or Flat Screen have dropped steadily, bringing the cost of these dramatic TV's within the budget of most folks.
For these reasons, we suggest that you consult your dealer or installer before making an arbitrary decision on the screen size you "should" have. As you can see your best choice may be very different from what a quick measurement of available wall space might indicate.
There are other considerations you should be aware of in addition to resolution. Your dealer can walk you through the details
INTERLACED VERSUS PROGRESSIVE
These terms have to do with how the TV builds the screen image. In the first, the TV draws two halves of a complete picture separately. The first half (called a "field") consists of the odd numbered scanning lines. The second field consists of the even-numbered lines. The fields are drawn one after the other so quickly that our brain integrates these two fields into a single picture or "frame." We call this an "interlaced" image because we create it by interlacing odd and even lines to form one complete likeness. All NTSC-format and many DTV signals are interlaced.
A "progressive" image, on the other hand, is drawn all at once. There are no odd- and even-numbered "fields" to integrate, just a series of whole images continuously followed by other whole images. All computer monitors use progressive scanning. Some DTV signals are progressive also. Progressive scanning usually produces clearer pictures of fast moving events (a basketball game, for example, or the chase scene from an action movie) than interlaced scanning can. Many people prefer it for that reason.
Just remember that for any given resolution, progressive signal is better than the equivalent interlaced signal. Ex. 1080i to 1080p While many resolution standards exist, most televisions adhere to 4 to 5 levels of resolution. The list of lowest grade resolution to highest grade resolution possibilities are as follows: 480i, 480p, 1080i, 720p, 1080p (note: 1080i signal is roughly equivalent to a hypothetical 540p signal which is not a television standard).
VIDEO CABLE TYPES
These formats are primarily used to get a video signal from one component to another. Before outlining some of the differences between these signal formats, you should know that video information falls into two main categories - luminance (brightness) and chrominance (color).
A composite video signal combines both luminance and chrominance for transmission through a single coaxial cable. Unfortunately, this reduces the signal's ability to convey fine detail. Although convenient, composite video signals are the least desirable in a high quality home theater system. Almost every video component has composite signal connections (Diagram 3-I).
An S-Video signal separates the luminance and chrominance portions of the signal. The result is improved detail and resolution. However, S-Video signals lose some of this advantage over longer distances. Many video components have S-Video connections (Diagram 3-2).
DVI video signals. DVI stands for Digital Video Interface and is one of the newer video signal formats. DVI is actually a predecessor of HDMI. Digital Video Interface was made by the Digital Display Working Group (DDWG). The original design for DVI included conversion of analog signals by converting analog into a digital signal. This was done so that both analog and digital signal monitors could be accommodated by DVI. Data is transmitted by the use of transition minimized differential signaling (TMDS) protocol and provides a digital signal to the display unit. There are actually three types of DVI. There is DVI-A and this type of DVI is used for analog signals like VGA. The second type of DVI is DVI-D. This type of DVI is used for digital signals, and this type of signal is the one that all home theater products use and that are intended for consumer home use. DVI-I is the third type . This type is a combination of DVI-A and DVI-D. Two levels of performance are supported by DVI-I. These levels are single link and dual link. Currently all home electronics products are designed around the single link standard. A dual link cable, however, is 100 % compatible with a single link cable plus the dual link cable offers the benefit of adaptability in the future for any wide band width applications. DVD-I is a complete, fully digital video transport protocol that is supportive of all digital video formats including 1080p.
Component video signals are similar to the RGB (red, green, blue) format used by video professionals. That's why a component video connection is the best way to go IF your video sources AND your TV are equipped with the three-connector terminations needed to send component video signals from one piece of equipment to another. HDMI video signals.High Definition Multimedia Interface is the only uncompressed, all digital audio/video interface that is supported by the industry. Founders of HDMI include manufacturers of leading consumer electronics Panasonic, Phillips, Hitachi , RCA, Sony, Toshiba, and Silicone Image. HDMI is also supported by motion picture producers Universal, Fox, Disney, and Warner Brothers, as well as system operators EchoStar and DirecTV. HDMI provides an interface in between any video/audio source, like an A/V receiver, digital television, and DVD player over one cable total, instead of one cable for video and one cable for audio. HDMI will support high definition video, standard video, and / or enhanced video plus multiple channels of digital audio on one single cable. HDMI will also transmit every ATSC HDTV standard and will support eight channel digital audio. HDMI has plenty of band width to spare so any future requirements and enhancements can be accommodated. There are two important differences between DVI and HDMI. The first difference is that HDMI technology incorporates content security that is called High Definition Content Protection, also known as HDCP. The other huge difference between Digital Video Interface and High Definition Multimedia Interface is that DVI can only support digital video, and HDMI can support audio and video on the same cable. All you really need to know is that today component or HDMI cables both offer excellent video signal transmission. HDMI continues to evolve, with improving performance at each new specification level. HDMI is easier to run, more expensive and limited in cable length to around 30 feet without an amplifier. Which cable should you choose? Do not assume that HDMI is the best cable for your new HDTV. Your sales consultant can help you select the best A/V interconnects for your situation.
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