LCD Projectors, I know nothing...

Discussion in 'Archived Threads 2001-2004' started by Jesse Steiner, Nov 21, 2002.

  1. Jesse Steiner

    Jesse Steiner Auditioning

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    Okay, I'll start off by letting you guys know this is my first post here, though i've been here a few times and read a little bit... I'm 16 years old. I own no equipment of my own, but if i had the money, i would buy some [​IMG] (lol, wouldn't we all?) I know about computers and car stereos, both of which relate to HT in some ways... But i'm definitely a novice, so anyways....
    I was talking to my architecture teacher today, and he gave me a different kind of assignment. He has a cabin that has been a work in progress for the last few years. Everything is rustic, he has no technological things that really stand out (small speakers hidden in a room or two, a TV in a cabinet with oak doors). He was looking through one of his log home magazines and I guess somebody had a projector setup in their living room. My teacher liked the idea of having a big screen, but being able to keep the rustic theme by hiding the projector and the screen. He is by no means a videophile or an audiophile, and his only reason for thinking about a projector, like i said, was how he could hide it.
    That being said, what do i need to know about projectors to get started on my quest for knowledge (well, i guess that actually started here...)? Like i said, he isn't a videophile, and there's no doubt in my mind that a cheap CRT would satisfy his desire for a good picture. I'm guessing the majority of the signal will be coming from a VCR, possibly a satellite (no cable, since this is in the middle of the woods). I will find out tomorrow whether he watches DVD's at all. But what i am trying to say is that we probably only need a 4:3 aspect ratio, and high resolution isn't a big factor.
    Will computer projectors work? I know the TV signal i'm used to has
     
  2. Neil Joseph

    Neil Joseph Lead Actor

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    I'm going to start by pointing you to this article that I am in the process of writing...
    Front Projection
    How do I select one for my my needs?
    First things first, let me first explain what front projection is. Basically what I am talking about is using a projector to project a video image onto a screen that is in front of the viewer. This is the same method used in movie theatres today with the screen at the front of the room/theatre and the video projector located towards the back of the room.
    With the prices of front projection coming down to reasonable levels, and with HDef becoming more accepted by the masses, more and more people are finding that a front projection system is within reach and an acceptable upgrade for their home theatres. There are a lot of questions that must be answered in order to know which type of projector is best suited for your home theatre.
    First of all, there are various types of projectors. I will not discuss the differences in this article in great depth but only cover the most important issues. The major types of projector consist of CRT, LCD, DLP, DILA and LCOS projectors, with the first 3 being the most common for home use. Each has its advantages and disadvantages so these must be factored into the final decision process.
    The MAJOR advantages/disadvantages between projector types
    1- CRT - The earliest front projectors were CRT (Cathode Ray Tube). Traditionally they were expensive, heavy, and difficult to set up but delivered top notch picture quality. Many are not as bright as the digital projectors of today so they will need a room that has absolute control of ambient light to prevent the picture from being "washed out". The biggest advantage though is their ability to produce very good "blacks". These units need to be set up at one point and not moved from that point. Once set up, convergence will also have to be done for best results. Many can be found used at reasonable prices.
    2- LCD - These digital projectors have become more and more popular today as they offer a lot of flexibility and ease of use. Prices vary from cheap to around the mid-point of the range of prices. Many offer zoom lenses that allow a range in their location because the picture size can be zoomed to the size of the screen, as well as keystone correction to correct for projector height in relation to the screen. Some of the things to watch out for are possible screen door effect where the pixels structure can be seen from a few feet away, and black level being more dark grey than black. These projectors can offer colours that are "punchy" when compared to other digital projectors like DLP. This is not necessarily true for all LCD and all DLP projectors though. Other considerations are bulb life and the "dead pixel" issue. Once a bulb has reached end of life, it will need to be replaced and could cost a couple of hundred dollars to do so. Sometimes an LCD projector can have what is called a dead pixel that does not change colour like it's neighbouring pixels do. This may hardly be visible unless you look very closely at the screen. You may observe a pixel that stays green all the time for example. The problem arises if there are a group of dead pixels together in one area which may cause it to be visible from the main viewing area.
    3- DLP - These digital projectors differ from LCD in the way they create an image but basically with DLP (Digital Light Processing), pixels are also projected at the screen. They offer many of the same features as LCD projectors with regards to flexibility and also some of the same concerns like bulb life. Screen door is less of an effect than LCD, typically, but not always. Contrast ratios can often be higher than with LCD, creating better blacks, but light output can also tend to be lower than with LCD. Often, the colours are less saturated and more washed out than with their LCD cousins. Other considerations are the "rainbow effect" that can be visible on many DLP projectors, typically those with slower colour wheels and some people have claimed getting headaches while viewing movies on some DLP units. The following is an interesting article from Texas Instruments on the concepts of DLP projectors and how a single chip revolutionized these projectors. dlp.com "DLP technology" (click "Launch our demo" under "See How It Works" on the upper right)
    4- LCOS & DILA - These are other types of digital projectors. There are presently not many LCOS or DILA projectors on the market for home use and they are also a lot more expensive.
    OK, so how do I select one for my my needs?
    There are various considerations to determine which type and model of projector is right for your setup. A useful search function can be found at Projector Central, that allows you to search on price, brightness, resolution, projector type, etc to help with the decision making process as well. Let me list the considerations and flesh out each one...
    Budget - This is perhaps the most immediate limiting factor. Obviously at the time I write this, the pricing will differ as time goes by which makes it hard for me to consider specific models. When considering budget however, one must factor in not only the price of the projector, but the price of a matching screen (a do-it-yourself screen is also an option), a mount for installing the projector to the ceiling, and cabling to the projector. Prices will vary greatly on each type of projector as well costing anywhere from a few hundred dollars for a used projector, to a couple thousand dollars for a new entry level projector, to a few thousand for a CRT, mid-range LCD, mid-range DLP, to ten thousand dollars and up for higher end LCD, DLP, CRT and LCOS projectors. In some cases, an outboard line doubler (or scaler) may also be needed. In effect, this increases the resolution of the picture being displayed so that the projector's maximum resolution can be utilized. A good projector will have decent internal scaling but if not, an external one can be used but this would need to be added to the budget as well.
    The screen & projector. 16x9 vs 4x3 - In order to determine which native aspect ratio (4x3 or 16x9) is better for your setup, you first need to know what source material you will be viewing more of, and where to make the necessary trade-offs. Many of the movies available on DVD (not all) for example are in widescreen format as opposed to 4x3 format. Most of the material broadcast on local cable TV is in a 4x3 format. HDef broadcasts are mostly in widescreen as well. If most of your viewing will be widescreen material then the native 16x9 resolution of a projector will serve you well. For instance, a movie like Toy Story which has a 1.78:1 aspect ratio will fill the entire 16x9 screen. Viewing the same movie on a 4x3 projector and screen will result in black bars on the top and bottom of the screen, and less of the resolution of the projector devoted to the movie. The flip side however comes when viewing 4x3 material on a native 16x9 projector and screen. In this case, you will get black bars to the left and right of the image. A third consideration to consider is most 16x9 material is of a higher quality than 4x3 material so choosing a 4x3 screen to view both widescreen and full frame on it will yield a widescreen movie with black bars on the top and bottom, as well as a blown up (large) 4x3 image that shows all of the defects of the 4x3 material. A complete article can be found at Projector Central for more reading... 4:3 vs. 16:9 - how to select the right format
    HT room dimensions, screen size, and projector "throw" - Room dimensions must be taken into account as well. The length of the room from the front to the back can come into play. The first thing that is important regarding screen size is that it is not recommended sitting closer than 1.5 times the screen width otherwise the image becomes too large to watch comfortably. Once the length of the room is known, you need to determine the screensize you would like to have, and if it will "fit" into the room. For instance, a 16x9 92" screen is 45" high and 80" wide so seating should be no closer than 1.5 x 80 = 120" or 10ft. You also need to determine if the particular projector can create an image of that size withing the boundaries (length) of that room and still have enough space behind for cooling purposes. This is also know as the projector's throw. Most rooms will have a high enough ceiling to accomodate the projector and screen but a very low ceiling may in fact rule out a possible front projection setup.
    Source material & resolution - Today's DVD resolution is 640x480. Some Hdef programming is broadcast at 720 lines progressively, or 720p, while others are broadcast at 1080 lines interlaced, or 1080i. DVHS's resolution is also 1080i and future formats like HD-DVD may also be this resolution. The resolution of the formats you watch, and the ones you would like to watch is another consideration. Projectors come in various 4x3 and 16x9 resolutions. I will list them with their resolutions...
    . VGA = 640 x 480
    . WVGA = 858 x 484
    . SVGA = 800 x 600
    . XGA = 1024 x 768
    . WXGA = 1366 x 768 or 1280 x 720
    . SXGA = 1280 x 1024
    . WSXGA = 1365 x 1024
    . UXGA = 1600 x 1200
    . QXGA = 2048 x 1536
    Obviously, the more pixels displayed, the less visible and smaller the pixels will be and the better the picture quality, all else being equal. Price tends to increase with resolution as well. Many projectors will "down-convert" a higher resolution to fit their native resolution but a projector that is capable of a higher resolution should be considered before one that has a lower resolution, all else being equal of course.
    Your HT room's ambient light, projector brightness & screen gain - Some of us are "fortunate" to have a room that can be totally light controlled (made pitch black even during the daytime), while others of us have room with lots of ambient light. Being able to control the amount of light in a room is very important, no matter what type of projector is used but a projector with higher brightness will be able to handle a room with ambient light better than a projector with low brightness. Many lower end projectors and some of the CRT units can have a brightness of 300 to 600 ansi-lumens. Essentially, these should be placed in a room that can be made totally dark. The better LCD and DLP projectors can be as bright as 1000 a.l. and some can be upwards of 1500-2000 a.l. Ambient light will wash out the colours and the blacks as well resulting in no shadow detail and rendering the picture un-watchable. Once you select a projector then a suitable screen must be selected to match it with an appropriate amount of gain. The higher the gain of the screen, the brighter the image on the screen and the more resistant the image is to a room's ambient light. A reputable home theatre store can usually recommend a suitable screen for a projector you choose but it helps to know the dynamics of the room, particularly how much ambient light it may have.
    Contrast ratio - What is contrast ratio? Contrast ratio is the range between the lightest and darkest light that a projector can produce. The higher the contrast ratio, the better a projector is capable of producing blacks on the image. This is where the better CRT projectors and the higher end DLP units shine. Make no mistake though, LCD technology with the higher end units is on par should not be ignored either. In any case, those with a lower on/off contrast ratio vary anywhere between 250 - 600 a.l. while some are 600 - 1000 a.l. or higher.
    Inputs/connections - At a minimum, a projector should have composite video, s-video, and component video inputs. Some projectors will accept progressively scanned signals so this is important if either using a progressive scan DVD player of a HDef signal. Other connections include a 12V trigger for a motorized screen and a DVI port. A DVI port (digital video interface), if a projector is equipped with it, allows an outboard scaler or home theatre PC (HTPC) to be used to scale an image to the highest resolution that a particular projector can accept, and can result in amazing images. The most common type of DVI connection is the 15- pin analog DB15 VGA style of connector that computer monitors use. Some others have DVI-D which is a digital 24-pin variant. For more information on DVI, read this article from Dell.com...
    http://www.dell.com/us/en/arm/topics...s_2000-dvi.htm.
    Other features/considerations - There are lots of different features that may prove to be of use to a potential buyer. Some of those include manual/power focus, manual/power zoom, keystone correction, lens shift, inboard speakers and more. The last consideration I will mention is bulb life, something that must be kept in mind with digital projectors. The higher the bulb life the less frequently it will have to be changed. As this is an expense, a higher bulb life will be advantageous. Typically, bulb life varies between 1000-2000 hours. Some projectors offer an "econo" mode that lenghtens the life of the bulb by slightly reducing the light output.
    Conclusion - Once you consider all of the above criteria, a list of hundreds of potential projectors can get narrowed down to a few, or even one that is the best in your situation. There are many online websites that contain specifications that help with the decision making process. As well, it is always best to demo a projector for oneself at a reputable local home theatre store rather than buy sight unseen.
     
  3. Neil Joseph

    Neil Joseph Lead Actor

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    There have been some memebrs here that have hidden their projectors and either have pulldown screens, or motorized ones that lower/raise when the projector is turned on/off. Motorized screens don't come cheap though. Computer projectors will work but the ting to watch out for are their contrast levels and their inability to produce good blacks (not all of them).

    Find out from him first what video sources he will be using and we can help you out.
     
  4. Jesse Steiner

    Jesse Steiner Auditioning

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    Wow, thanks for all the information!

    Okay, i went and talked to my teacher, and he surprised me buy telling me a few things i didn't expect.
    1) Price is not an issue (though when i mentioned a $5k projector i can get at a local store, he laughed at the idea of five thousand dollars for a projector.)
    2) He plans on watching DVDs and VHS tapes only (no TV signal), and he is concerned with PQ
    3) The room is about 24' long, and he partially plans on designing the room around the screen.
    4) He wants to buy a screen, but it doesn't have to be motorized, only pull-down. Any suggestions? What is there to look for in a screen?
     
  5. Neil Joseph

    Neil Joseph Lead Actor

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    If he is really concerned about picture quality then his VCR is the weak link in this equation. Since he laughed at the idea of a $5K projector then I would probably suggest either a Dalite or Draper pull down screen.

    You need to find out from him whether a 4x3 screen and 4x3 projector would suit him as apposed to a 16x9 screen and 16x9 projector. Take a look through my first response in this thread under "The screen & projector. 16x9 vs 4x3" for help. In my situation for example, I watch solely DVD's on my projector but have planned for HDTV and HD_DVD and most of the material I watch is widescreen so I went with a 16x9 screen and a projector that has native 16x9 panels. This way, the entire panel is devoted to displaying a widescreen movie (with a 1.78:1 aspect ration like Toy Story for instance) and the result is an image with a significantly higher resolution in widescreen.
     

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