plasma / lcd / DLP? In the market for a BIG tv

[Publius]

Originally Posted by DosEquis

It is a nice tractor and dumpster... but i suspect they are temporary

[7960]

Originally Posted by DosEquis

It is a nice tractor and dumpster... but i suspect they are temporary

they are, but I wouldn't mind if he left the backhoe

and I'll tell you what......the dumpster looks like crap but it's SO nice being able to walk out and toss stuff. I cleaned out the basement last weekend. Got rid of all that shit that accumulates for no good reason.

[Stylerod]

Originally Posted by 7960

they are, but I wouldn't mind if he left the backhoe

and I'll tell you what......the dumpster looks like crap but it's SO nice being able to walk out and toss stuff. I cleaned out the basement last weekend. Got rid of all that shit that accumulates for no good reason.

I keep telling my wife I'm going to get a dumpster. I think our foundation is cracking from the weight of all the crap we have. Especially in the kids rooms.

[DosEquis]

But for serious... I have the 42 inch version of this...also with a window behind it. Though I do not have a tractor and backhoe landscaping, the anti-glare screen gives me the LCD-like non glare look, but with the performance of the plasma. It gets great reviews just about anywhere and I have been more than happy with it. I think its only knock is that it is limited on inputs compared to some of the other brands/models but this one is also pretty reasonable on the price tag.

Panasonic TH-50PX77U

[7960]

Originally Posted by DosEquis

But for serious... I have the 42 inch version of this...

Panasonic TH-50PX77U

I think I have the 42" version of that, too, and I'm happy with it. But like I said, I haven't checked out TVs for 2 years and didn't know if there's something else worth checking out.

thanks

[7960]

Originally Posted by Stylerod

I keep telling my wife I'm going to get a dumpster. I think our foundation is cracking from the weight of all the crap we have. Especially in the kids rooms.

friend/neighbor across the street had his wife get him one for father's day last year

he filled it in a weekend.

[Donkey®]

What is HDTV?

High definition television is basically the next generation of broadcast television that uses a digital signal to provide higher resolution images than the traditional broadcasts that we have been using up until now (SDTV). HDTV has been around since the 1990's and is just now beginning to gain critical mass in terms of widespread adoption by the general public.

According to the HDTV specifications used in the United States, HDTV is a digital broadcast that is presented in a 16:9 format that has either 720 progressive scan lines of resolution or 1080 interlaced or progressive lines of resolution. Overall the resolution increase overSDTV is anywhere from 2-5 times.

Generally speaking, HDTV has many advantages over SDTV in color reproduction, signal transmission, high resolution digital audio, and overall wow-factor.

Resolution, Screen Format, Frame Rate - Basics

The basic thing that sets apart HDTV from SDTV is resolution. Along with that though, the issue of frame rate and screen formatting is also something that HDTV has over SDTV. As mentioned earlier, HDTV provides either 720 progressive or 1080 interlace/progressive scan lines of resolution. These resolution formats are denoted in shorthand as 720p, 1080i, and 1080p. The numbers represent the vertical resolution of the screen. Note that the horizontal resolution is not expressly denoted, but is in fact implied as the following...

720p = 1280x720 pixels progressively scanned
1080i = 1920x1080 pixels interlaced
1080p = 1920x1080 pixels progressively scanned.

Part of the reason that the horizontal resolution component is left off is because older TVs mainly consisted of CRTs. CRTs don't really correlate to pixels as such and therefore, the only thing that made sense was scan lines, or vertical resolution. Plus, human vision is generally more sensitive to increases in vertical resolution rather than horizontal resolution.

When discussing resolution, frame rate or scan rate must also be specified. When we are talking about HDTV standards, the terms progressive (p) and interlaced (i) are thrown around all the time. So what really do we mean when we say ___x____ resolution progressive scan? Simply put, what progressive means is that the full screen (all ___x____ pixels) is redrawn at the same time in one refresh period. The refresh period is what determines how much time elapses between successive redrawing of the full screen raster. Now that we have an idea of progressive, what does interlace mean? Interlace scanning is when half of the screen is redrawn in one refresh period. When we say half of the screen, what we mean is that in one refresh period either the odd numbered fields or even numbered fields are redrawn. If you imagine the vertical resolution to be numbered 0 through 1079 (1080 lines), then in a single refresh period, either the 540 even numbered lines, or the 540 odd numbered lines are redrawn. What this results in is the entire screen being redrawn, or refreshed, in twice the refresh period rather than a single refresh period with progressive scan.

Now that we have an idea of the difference between progressive scan and interlace scan, we can now discuss frame rate. As mentioned above, interlace or progressive scan is tied to a rate (fields per second, or fps), or time in between when the screen is redrawn. This represents how fast the screen is redrawn. HDTV has a few refresh rates specified:

24p = 24 progressive frames per second
30p = 30 progressive frames per second
50p = 50 progressive frames per second
60p = 60 progressive frames per second
60i = 60 interlaced frames per second

What do these numbers mean... lets take an example of 60p. What 60p means is that in 1/60th of a second, the entire screen is redrawn. So if we have a 1280x720p 60fps display, then all 1280x720 pixels are redrawn every 1/60th of a second. How does this work with 60i then? With 60i, half of the frames (even or odd) are redrawn every 1/60th of a second which means that in one 1/60th time period the even fields are redrawn, and in the very next 1/60th of a second, the odd fields are redrawn. This results in the entire screen being redrawn in 1/30th of a second.

So what is better? Clearly, higher resolutions obviously result in higher pixel count and more detail. In terms of pixels on screen, 1920x1080 = over 2 million pixels while 1280x720 = just under 1 million pixels. Huge difference? Not really... The human eye is much more sensitive to vertical resolution than to horizontal so the increase in horizontal resolution is not as big. Secondly, if the 1920x1080 broadcast is interlaced, then you are really only seeing half of the resolution if the image is moving. With a static image, you do see more pixels, but once motion is introduced, the difference between a 720p broadcast and 1080i broadcast is minimal. Many will argue that 720p is actually better for fast motion because of this.

HDTV is presented in what is called a 16:9 format. This ratio is the ratio of the horizontal screen length to vertical screen length. Standard definition TVs are 4:3 ratio and are sometimes referred to as 'full-screen' as opposed to 'widescreen' (16:9). The widescreen format is also referred to as a 1.85 aspect ratio. HDTV shows are all 16:9 format. When viewing SDTV on 16:9 displays, you have the option of viewing black bars on the sides or streteching the image to fill the screen. When viewing DVDs that are widescreen, many people still complain of black bars on top and bottom. This is normal as the DVD is presented in what is called the 'Original Aspect Ratio' (OAR). OARs range from 1.85 (HDTV) all the way up to 2.45. The higher the number, the larger the black bars will be top and bottom. This is perfectly normal.

Resolution and Format Conversion

One of the keys in HDTV shopping is finding out what the true native resolution of the display is that you are looking at. Every spec sheet on every display device will list the native resolution, for example, 1280x720 pixels progressively scanned at 60fps. That right there tells us that the display device is capable of displaying one of the HDTV formats in its true, unaltered sense. Now what will also be promoted is the fact that it accepts all the other formats as well. For sure, the display device will do exactly that, but it will do so by altering or rescaling the original format image to its native resolution and scan rate. What this means is that the overall picture quality of the image you are viewing will be directly related to how good this scaling process in the display device actually is. In many cases it may be true that when you feed a display device one resolution, it looks great, while other times it may seem other resolutions result in softer images lacking in detail. This may be attributed to the scaling process that is involved.

One factor that is quite difficult to ascertain is frame rate conversion. Resolution is an easier problem to visualize, but frame rate conversion is something that is not often considered. A display that is natively a progressive device needs to handle interlaced format as well. How it handles these is tantamount to how good the resulting picture for that resolution will be. For example, if we take a display that is 1280x720p 60fps and feed it a 1920x1080i 60fps signal what is the proper way to display the image? We are receiving 540 even and odd lines every 1/60th of a second so we have a few ways to take this information and display it at 1280x720p 60fps.

* Simply discard every even (or odd) 540 fields and take the one and scale it to 1280x720 from 1920x540 (very cheap)
* Scale each 1920x540 field to 1280x720 and display every other resulting image offset from one another
* Deinterlace the 1920x1080i image to 1920x1080p and then scale back down to 1280x720 (very expensive)

Displays that choose the first method will suffer when displaying a 1080i format image. Displays that perform the second method will introduce some flicker as the offset fields are alternated. The third would be perfect if and only if the deinterlacing (conversion from interlace to progressive) was good. This example can be followed the other way as well when taking a 1280x720p 60fps image and converting to 1920x1080i. In this case, each 1280x720 field will be scaled to 1920x540 every 1/60th of a second and then the even and odd fields will be displayed.

This brings us to a small discussion of deinterlacing. Deinterlacing is the process of taking an interlaced image and converting to a progressive image. This is not a simple process and is very often where display devices falter. SDTV, DVDs, and many other sources are inherently interlaced. These sources must be deinterlaced before they are to be displayed on your shiny new HDTV. How good these sources look is directly determined by the deinterlacing performance of the display. Standard DVD players that are progressive scan use specialized hardware for this exact process. In some cases, the deinterlacing of the player may be better than that of the display and in many cases, the display me do a better job of the conversion as discussed in the examples above. Motion adaptive deinterlacing is a very complex process that is not really easy to discuss here, but lets take some simple examples to show the problem. Standard cinematic DVDs are 720x480i at 24fps. How do we display this source properly on a 60fps device? We are receiving 24 interlaced fields every second and must translate that to a 1/60th of a second refresh. In order to achieve this, the conversion needs to produce 5 video fields from each 2 original film frames. The first film frame produces 3 video fields: a field of the odd numbered scan lines, a field of the even numbered scan lines, and a repeated field of the odd numbered scan lines. The second film frame produces 2 video fields: a field of the even numbered scan lines, and a field of the odd numbered scan lines. This conversion process is known as 3:2 pull-down.

All of this is fine and good, but what does it mean in buying a new HDTV? Armed with this information, we can look at a display spec sheet and see what its native resolution is. It is generally a safe assumption that a display will produce a good picture when being fed its native resolution. The question is how well it displays other resolutions that are not native. This can only be determined after careful viewing. Many display devices that are marketed as high-definition DO NOT actually have a native resolution that is one of the HD resolutions specified above. These devices are always scaling the input picture to their own native resolution. One must be careful in determining how good the quality of these such devices are when being fed a variety of different resolutions. Again, they may acceptHD resolutions, but do not actually display them in their true native format.

Another consideration regarding resolution when selecting a display device is how good SDTV looks on these devices. In many cases, SDTV broadcasts look quite poor on large HDTVs. This is because the TV has to take the original 480 interlace field image and scale it up to the native resolution of the display. Simply put, information can not be created from nothing and the result is generally not very good. Performance ofSDTV may or may not be a consideration in your selection.

One recent development in HDTV are 1920x1080p displays. These displays are marketed as 'Full HD' and touted as being light years better than the older 720p/1080i displays. Lets examine this for a second. Currently, there is no broadcast material available in 1920x1080p 60fps. In fact, it is actually not part of theITU HDTV spec. This type of display will take every 720p broadcast and convert it to 1920x1080p and take every 1920x1080i broadcast anddeinterlace it. The 720p image is a simple scaling as it is already at 60 progressive fps and the scaling is a simpler problem. The 1920x1080i image must be properlydeinterlaced to 1920x1080p. How good this deinterlacing and scaling is determines how much, if any, the resulting image is over previous displays. The same issue lies here if the input resolution is 1920x1080p 24fps, which in fact is aITU HDTV spec. The only complication here is converting from 24fps to 60fps using 3-2 pulldown as described above. In short, how much better these displays are depends on how they scale and deinterlace . In many cases, they may look no better than a good 720p or 1080i display. Furthermore it must be noted that many displays that do have a native 1920x1080p resolution may not in fact accept 1920x1080p as an input in any form. Be careful here.

Beyond Resolution

As we have seen, resolution is a key factor in HDTV. It is one of the first things that is noticeable in a display. However, that is not the only metric for measuring the quality of a display. Resolution increases beyond a certain point yield diminishing returns due to the inherent capabilities of the human eye. This is where other factors such as dynamic range and true color reproduction come into play. These factors turn out to be just as important as resolution and may very well help you pick out the right display.

Dynamic range is basically a term that describes how far apart the extremes are from one another and in the case of displays, it determines how far apart, in terms of luminosity, the brightest and darkest color the display can reproduce are. It also represents how many finegradation nulls or steps there are between the blackest black and whitest white. Another more common term for this is Contrast Ratio, which manufacturers throw around all the time. To visualize what contrast ratio means, lets take a display such as a CRT. A CRT will produce black as just that, pure black. In other words, black will be the presence of no light while it will produce white as the presence of all the colors. Theoretically, a CRT will have an infinite contrast ratio since no light is emitted when the display shows black. So what complicates the matter? When it comes to current display technologies manufacturers are free to define contrast ratio in any way they please. With devices such asDLP and LCD which use a common light source, the black level is not really a true black since there is never any absence of light. Black in this case may be at worst a darkshade of gray or at best a very dark black, but never true black.

There are two main methods for specifying contrast ratio: on-off and ANSI. On-off contrast ratio numbers are more dubious as all that tests is the blackest black against the whitest white the display can produce both taken as separate displays. This method can potentially produce astronomical numbers for contrast ratio since the black measurement is taken in the presence of only black and white is measured with the presence of only white. This is also often referred to as the dynamic contrast ratio. ANSI contrast ratios use a black and white checkerboard pattern to determine contrast ratio. Here, the black part of the checkerboard is measured against the white part and then the ratio isformulated . This is a truer measure since we have both black and white present in the same image at the same time. This gives a truer representation of the contrast ratio. The ANSI method results in what is called the static contrast ratio.

So what does contrast ratio do for you? Simply put it determines how realistic an image really is. For example, if you are viewing a display that has a very dark night scene, a display that has a poor contrast ratio will show much of the scene as just plain black since it won't be able to differentiate between a dark gray and black. Details in shadows and dark spots will be lost. A display that has a high contrast ratio will be able to correctly display more of the information in the dark areas since it can differentiate between a dark gray and black.

Accurate color reproduction is another important category in displays and goes hand in hand with dynamic range. This is where accurate grayscale settings are important. Grayscale sets the middle point from which all colors, red, green, and blue are referenced. If this is not properly set, the three component colors will never be accurate. Many displays do not trackgrayscale linearly or properly and almost never do out of the box. Assuming that grayscale is set correctly, the dynamic range and quality of the color decoder will determine how accurate the display is. How the colors are generated in the display determines this to some extent. The phosphor on a CRT will yield very accurate colors since it has nearly infinite number of steps in between successive color levels. A purely digital display may use only a handful of colors mixed in a certain way to reproduce the same color. To get around that, many digital displays introduce dithering to 'hop' between neighboring colors to smooth out these discrete steps.

[Donkey®]

Choosing a HDTV

Now that we have a basic notion of what some of the factors are in display technology, lets see if we can apply this to actually selecting aHD display device. First and foremost, two things must be considered and nailed down prior to doing anything: viewing environment and budget. After that, it comes down to what you are willing to accept. Since pricing is changing so rapidly, I am not going to go into that so much, but I will say that for a given price, a rear projection based system gives you the most bang for the buck when it comes to features and screen size.

Viewing Environment

There are a few things relating to the viewing environment that need to be considered. First and foremost will be determining viewing distance. Viewing distance is the main thing that determines what resolution and screen size you need to target in your TV search. Here is a great chart that sums up how screen size relates to resolution



Just find your viewing distance on the y-axis and try and see what screen size and resolution you arrive at given different choices... For example I sit 10-11 feet away from a 52" screen. For me, I can clearly see the benefit of 720p, but 1080p may or may not give me a big jump in perceived detail. What we can see from this is that viewing distance will directly determine how much resolution we canperceive for a given screen size. For example, there is no need for a 1080p TV that is 50" if you plan on sitting 20 feet from it.

Another factor relating to viewing environment is ambient light. If the place you plan on using has a lot of ambient light due to windows or whatever, certain display technologies and screen types may not be right for you. Reflection of ambient light will cause the contrast ratio to suffer if the level of this light is too high. A display may look washed out or dim when viewed in a bright room. This makes displays that are inherently dim look even dimmer.

Viewing angles are another consideration when thinking about your room. Every display is going to look great when viewed dead center. But what do the guys sitting around you see? Is the display mounted high up on the wall where it looks all washed out? If viewing angles are going to be kept to 60 degrees horizontally and a few degrees vertically, than any display would be fine. But wider viewing angles are not supported by all display types.

Connection Types

Look at the back of a TV these days and you will be assaulted with tens of connectors. Not really an easy proposition for someone who isn't familiar with what they do. Lets do a run down of them

* Coaxial: This is your standard cable connection that you screw a cable into. If your TV has an internal tuner, then you want to hook up your cable or antenna feed here. Your TV will demodulate the cable or off-the-air digital signal. You do not want to use an external tuner and feed that here though. Find a better connection if available since RF modulated outputs are generally poor.
* Composite: This is a single RCA jack usually colored yellow. It carries video only and is limited to a maximum resolution of 480i (SDTV). Avoid use if possible
* S-Video: A black connector with 4 small holes and a plastic tab with a ground ring. Better than composite, but still limited to 480i resolution video only. If you have an old VCR that has S-video, use this.
* Component: Three RCA jacks labeled YPrPb usually and colored red, green, and blue. The best of the analog connections that supports 480i, 720p, 1080i, and in some cases 1080p. Use this for yourHD hookups.
* VGA: Same as the VGA connector on your PC. Used to hook up PCs mainly but can also be used for HD resolutions. It is analog and uses RGB format for color.
* DVI: Small rectangular connector with 24-pins plus a crosshatch. Carries digital video signals and can be used with PCs and other AV equipment supporting all resolutions up to 1080p.
* HDMI: Supports the same resolutions as DVI but also carried digital audio. Depending on the version supported may support a wider color space as well as higher resolutionLPCM audio formats.
* Firewire: Carries all HD resolutions and digital audio. Video may either be MPEG or DV format... not widely used.

The analog connections are relatively simple but the digital connections such as DVI and HDMI are not so easy. HDMI connections require the use of equipment that is HDCP compliant. HDCP is a hardware authentication handshake that the devices you are connecting must support. This is done to ensure that the data carried on the connector is encrypted so you can't copy it. What this means is that if you use a device that requiresHDCP into a display that does not, you will either get no image or only be able to use a maximum resolution of 480p. This may or may not apply toDVI as well. Some DVI inputs support HDCP, while some don't. You can thank the big movie studios for pushing this crap on the consumer.

Now we come to the question of what is better... an analog connection, or digital. Again, the answer here is "it depends". You will hear people say that digital is best without really explaining why. We can spend pages and pages talking about digital to analog conversion, sampling, oversampling, etc... but lets just look at it as a whole. The conversion from digital to analog is not a simple process and is not perfect. With that said though, it can be very very good up to the point where it doesn't matter. DVDs and digital broadcasts are stored as digital and played back as digital prior to hitting a connector. So lets take a cable box as an example. It receives a digital signal over your cable line and demodulates it into a digital video signal. Now if you used a component hookup to connect it, this digital video signal is converted to three analogYPrPb signals and output. The signal travels over the cables and enters the TV. If the TV is digital, then this analog component signal is converted back to digital, processed, and then put out to the display. Had we used a digital hookup such asHDMI, the digital signal would leave the cable box unaltered, travel over the HDMI link, and hit the TV. The TV would then take the raw digital bits and process those directly. In this way we avoid two D->A conversions. What can complicate this is the fact that the final display is sometimes analog itself. In the case of a CRT or even an LCD, the final value sent to the display is analog. In that case, it may not matter at all whether you send a digital signal or not since it must be converted to analog anyways. In the end, it depends on the quality of the conversion process and the quality of the display circuitry that is processing the signal. The simple answer is to experiment.

What may further complicate matters is the fact that the HDMI signal path in a TV may use completely different color conversion from the component color space. This may lead to drastically different picture quality if the settings are not adjusted independently on each input type. I am not getting into it here, but you can look up the differences betweenRGB color space and component color space conversion.

[Donkey®]

Display Type

Here is where things can get even more complicated. So far we have avoided how HD is really implemented in different technology. To break things up I would like to categorize it into the following types:

* Front Projection
* Rear Projection
* Flat Panel

Each has different applications and viewing requirements and selecting the proper one takes some thought. I will just go over an overview of each.

Front Projection

If you have a dedicated viewing room with ambient light control and space to spare, this is the one for you. Screen sizes are measured in feet here rather than inches. Front projectors 'throw' an image onto a reflective screen for viewing in this case. You buy the projector and screen separately here and take into account your projectors optimal throw length along with the screen size you want. Lighting control is very important here as it is easy to wash out a projected image with too much ambient light. I personally do not know very much regarding front projector setup, but this website will guide you on your way:

Projectors, Projector Reviews, LCD Projectors, Home Theater DLP Projectors at ProjectorCentral.com

When purchasing a projector, light output is key as well as resolution and screen format. These can be tweaked quite a bit to achieve a great looking image. Projectors generally lack a wide variety of inputs so the use of a receiver or video switcher may be necessary to hook up all your gear. These come in different technologies ranging from CRT, LCD,DLP, and D-ILA/LCOS. Most projectors except for CRT based ones use a replaceable bulb that must be replaced when burnt out.

Rear Projection

Rear projection TV sets are where one finds the most bang for buck in terms of screen size and performance. Sizes range from 42" all the way up to 70" and TV set sizes can range from 12" thick to a few feet thick depending on the display technology used. These are meant to be placed on a stand or table and are not conducive to wall mounting. Lighting control is not as big a factor but will still have some impact because of screen glare and other reflections. The way things work here are images are created on small display engines and then projected using lenses and mirrors onto alenticular screen. You are watching a projected image, but you can't tell that by just looking at it. One drawback of rear projectors is viewing angle. Horizontal viewing angles are fairly wide depending on the technology used, but vertical angles are limited quite a bit. Just standing up may affect your viewing.

These types of displays usually have the most varied set of connections and features. They can be dialed in pretty well to achieve a great image as well. These can be found as CRT based displays,DLP, LCD, and LCOS/D-ILA/SXRD . Except for CRT based rear projection sets, all use a mercury or halide bulb as a light source. This bulb usually burns out after thousands of hours of use and must be replaced. Replacement bulbs are usually in the range of $200 - $300 and once the bulb is replaced, you have a new TV again. Periodic maintenance in the form of mirror cleaning may be required from time to time to keep the set looking sharp as well.

Flat Panel

Flat panel TVs are the new emerging trend in HDTV. Previously, they were either too expensive or produced sub-par picture quality given what they cost. Much of that has been improved over the past several years and they have become a viable option for the regular consumer. Screen sizes for flat panels areusually in the 38" to 50" range with some larger and smaller models as well. Generally consumers are drawn to these TVs because of their unobtrusive size and flexibility. They are often wall mounted and are well suited for tight spaces. Viewing angles are also fairly good on these displays and are noticeably better than rear projectors. Where these displays do suffer at times is in contrast ratio and/or responsiveness. For the price, they are still an expensive lot given the features and resolution you get.

Plasma and LCD flat panels are the two main types of technology here. Connections on flat panels vary greatly by manufacturer and model. Some may be plain displays while others are more like full function TVs. Many flat panel displays do not have a nativeHD resolution and as such must scale every input resolution to their native panel resolution.

Display Technology

Within each type of display type there are different display technologies that are used. They have been mentioned earlier, but the details of their operation have not been explained. Each has advantages and disadvantages over another.

CRT

CRT is an older technology that has been around for a very long time. It is used in rear and front projectors. Note that this is different from direct view CRT where there is a single electron gun that illuminates the phosphors. In front and rear projectors there are three CRT guns, one red, green, and blue. These three guns illuminate phosphors that are optically combined and projected. As such there is no notion of pixels when it comes to CRT based displays. The guns inherently have a resolution limit and the larger the gun, the higher resolution it is able to resolve. 7" guns are common and 9" guns are used in high quality CRT projection systems. One point to note is that in reality a 9" CRT gun will at maximum be able to resolve 1500-1600 pixels of horizontal resolution and even less for a 7" gun. Given that CRT displays were almost exclusively 1920x1080i, the actual horizontal resolution is not really 1920, but a bit less.

CRT based displays have the distinct advantage of black level performance. As stated previously, CRTs are theoretically infinite contrast ratio devices as they can produce the blackest black (absence of light). Also due to the lack of pixel structure, they are very flexible in producing images of varying resolution while maintaining a smooth appearance. Cost is another advantage for CRTs as they have been around for a very long time and are fairly reliable. The analog nature of CRT based displays allows them to reproduce colors very well. Analog and digital sources can be made to look great with CRTs.

One main drawback to CRT based displays is size. They need to be large to house the gun based projection system and as such are tough to fit in rooms at times. Maintenance is also necessary for CRTs since they need to be periodically adjusted to retain convergence between the three guns. Over time the guns convergence circuitry drifts causing the guns to not line up perfectly. This needs to be adjusted time to time to retain proper color reproduction. CRT based displays are also susceptible to burn in when using static images as they may cause the phosphor to burn in unevenly.

CRT based displays still to this day are capable of producing some of the best looking HD images with a wide variety of sources. Their analog nature produces some of the most colorful and smooth looking pictures amongst all the display technologies. Even with their drawbacks and required maintenance, they are a great buy since they can be found so cheap.


DLP

DLP stand for Digital Light Projector and is used in both front and rear projectors. DLP uses a mirror device that consists of an array of mirrors (DMD) that are turned on and off rapidly. The DMD is an array of either 1280x720 (720pdisplay) mirrors or 1920x1080 (1080p display) mirrors that tilt back and forth to produce a grayscale image. A light source is used and passed through a rotating color wheel that has 6 or 7 different colors. The DMD mirrors tilt towards and away from the colored light source to mix the colors into a coherent image. This image is passed through a projection lens.

DLP based displays have the ability to accurately reproduce colors very close to a CRT. Also because of the fine mirror structure, the individual pixel spacing is quite small and the pixel structure is not easily visible.Response time for DLP based displays is very good as they only need to switch mirrors on/off to react to a changing image. They also have fairly good contrast ratios as the mirrors can be turned 'off' to reproduce black.

One main drawback to DLP is what is referred to as the 'rainbow effect'. This is caused by the spinning color wheel. Since the color wheel spins through 6 or 7 solid colors, some viewers may be able to shake their heads or dart their eyes fast enough to catch this transition of colors thus producing a rainbow of light in the image. This has been improved by both adding more colors to the wheel and speeding it up to where the human eye is not fast enough to detect the color changes. The vast majority of people never see this effect. Even thoughDLP has good dynamic range and contrast ratio, it is still not as good CRT in black level performance. This is because the bulb in the display is always on even when displaying black. How good the contrast ratio is depends on how much light the mirrors pass in the 'off' position.

LCD Projection

LCD rear projectors use three transparent LCD panels, one red, green, and blue, to produce an image and combine it optically. A light source such as a bulb passes through these panels while the individual pixels open and close on each panel to block or pass the light. In this way the colors are modulated with the light source to produce an image through a lens.

LCD projectors are very good at producing bright, well saturated images. Since there is no color wheel, all three primary colors are present simultaneously to make for a well-saturated image. LCD projection based displays also tend to be the brightest in terms of light output which makes them usable in environments where ambient light is an issue.

One issue with LCD projection has to do with pixel structure. In many cases, LCD panels have noticeable gaps between adjacent pixels. This gap makes the pixel structure visible and causes what is known as 'screen door effect'. This is where it seemslik e the image is being viewed through a screen door because of this gap. Black level and contrast ratio are antoher area where LCD projection sometimes suffers. LCD panels can only block so much light. With a bulb that is always on, some light is always let through. This causes poor black levels. Manufacturers are finding ways to improve this by using a dynamic iris to reduce the bulb output for darker scenes. Also LCD panels can possibly degrade over time since they are inherently made of organic material.

LCOS/D-ILA/SXRD

LCOS (liquid crystal on silicon), D-ILA (Direct Drive Image Light Amplifier), SXRD (Silicon crystal reflective display) are all very similar in nature to one another and are also sometimes called 3-chip DLP. LCOS is a gneeric term while D-ILA is JVC's implementation and SXRD is Sony's. There are slight wrinkles to each one, but the overall idea is the same. The microdisplay consists of three LCD panels, red, green, and blue. But rather than passing light through them like in LCD projection, the LCD material is placed on a reflective silicon substrate. The LCD crystals open and close, the either reflect or block the light and this modulation creates the image.

LCOS based implementations are noted for having a finer pixel structure than your standard LCD panels. This leads to the pixel structure being non-visible and there is no 'screen door effect'. Images produced this way are even smoother thanthose produced by DLP and LCD and the color fill is very good. Since all primary colors are available all the time, there is no chance for 'rainbow effect' either as there is no sequential mixing of colors.

The main drawback to LCOS type technology is black levels. Here again, LCD panels are not able to reach the full 'on-off' performance that can be found withDLP mirrors. Again this can be helped by using a dynamic iris for the light source. Depending on the type of substrate and LCD material used, this type of technology may or may not degrade over time.JVC's D-ILA implementation uses no organic materials in their implementation.

LCD Flat Panel

LCD flat panel technology has come a long way from the standard usage on computer desks everywhere. Countless numbers of TV displays are now LCD based. LCD flat panel displays are an array of liquid crystal molecules sandwiched between color filters and polarizing filters and electrodes. Each LCD pixel consists of threesubpixels , again, red, green, and blue. An electric field is applied across the electrodes that twists the LCD molecules and controls eachsubpixel to yield a color. LCD flat panels use a fluorescent backlight to illuminate the LCD array.

LCD panels are able to produce bright, vivid images. When being fed their native resolution they are able to produce very sharp, pleasing images. Many of the drawbacks that plagued LCD flat panel displays are no longer a major issue. That combined with their small, unobtrusive size makes them very appealing in the eyes of the public.

With that said though, LCD flat panels still have a ways to go to achieve the performance of other technologies. Mainly contrast ratio is where LCD flat panels suffer the most. Black levels just aren't there as compared to other technologies which causes them to appear washed out in dark scenes. Less expensive LCD panels do not have the dynamic range to be able toreproduce colors as well which makes their color accuracy imperfect. More recent LCD displays have gotten better at this. Response time is another major issue with LCD flat panels. This combined with their inherent input lag may cause fast moving scenes to blur or break up causing motion artifacts or what looks like a garbled image. Increasing panel speeds do help with this but with a response time on the order of milliseconds, these are the slowest displays of the bunch. Some LCD displays may also have an issue with image persistence where a static image left up on the screen may 'ghost' and look line burn-in. This is not permanent however and the panel will return to normal after viewing something else.

Plasma

Plasma flat panels are the hot display technology everyone wants now. Plasma display panels (PDP) consist of an array of xenon and neon gas cells that make up pixels. These pixels are sandwiched between two glass plates along with electrodes. When an electric field is applied, the gas is excited and ionizes. This ionization causes the emission of photons. Plasma cells are broken up intosubpixels , again, red, green, and blue, which are coated with the same phosphor used in CRTs. This phosphor causes the photons to give off a light much like that found in a fluorescent tube light.

The size of plasma screens is why consumers are drawn to it mainly. Plasmas are generally very thin and have very wide viewing angles allowing flexibility in placement. They have very good contrast ratios and dynamic range. They are very color-accurate as they use the same phosphor found in CRTs. Also, response time is not much of an issue as it is with LCD flat panels.

The main drawbacks with plasma has to do with price for a given resolution. HD resolution plasma displays are still quite expensive and some do not support HD resolutions natively. Burn-in is also a concern with plasmas. Since they use the same CRT based phosphors, static images can permanently burn-in on the display. This has gotten a lot better recently, but it is still possible. Also, plasma panels dim over time with the repeated ionization of the gas. Plasma life has gotten much better over the years, but it still has a finite life. Most newer plasmas have half lives of over 50000 hours so most users would not ever see the end of a plasma display making this a minor issue.


Conclusion

Selecting a new HDTV can be a daunting task. With all the marketing and hype surrounding technology, it is tough to see what is real and what isn't. Hopefully armed with this information you will be able to make an informed decision. Pretty much every display type and technology is a compromise in some way. You need to be able to take those compromises and select the type of display that is right for you depending on your needs and budget.

[7960]

ok, I think I've come to the conclusion based on lighting, viewing angle, viewing distance, etc, that I need an LCD in the 60" range........ (54" to 62")

suggestions for specific brands/models?

[Linzyhop]

Originally Posted by 7960

ok, I think I've come to the conclusion based on lighting, viewing angle, viewing distance, etc, that I need an LCD in the 60" range........ (54" to 62")

suggestions for specific brands/models?

sharp aquos

52"
Sharp - AQUOS 52" 1080p Flat-Panel LCD HDTV - LC-52D64U

65"
Sharp - AQUOS 65" 1080p Flat-Panel LCD HDTV - LC65D93U

[7960]

Originally Posted by Linzyhop

sharp aquos
http://images.bestbuy.com/BestBuy_US/images/products/8334/8334322_sa.jpg[/IMG]
52"
Sharp - AQUOS 52" 1080p Flat-Panel LCD HDTV - LC-52D64U

65"
Sharp - AQUOS 65" 1080p Flat-Panel LCD HDTV - LC65D93U

and putting down the crack pipe and taking cost into consideration??

seriously, I'm not spending $9,999 on a tv.

[Linzyhop]

Originally Posted by 7960

and putting down the crack pipe and taking cost into consideration??

seriously, I'm not spending $9,999 on a tv.

then get the 52" for $3000. if you're going to go that big, you want to spend the money, otherwise you're gonna get crap.