How to buy ... a home theatre projector

For serious film and sport fans, nothing gets close to the big picture experience of a projector.

By PC World Staff / Monday, August 14 2006

For serious film and sport fans, nothing gets close to the big picture experience of a projector.

The Big Picture
Films are made for the big screen, so why hanker after an expensive 42-inch plasma or LCD television when you can get images of up to 300 inches for far less money?
Even a basic projector gives a 200-inch picture, while the more you spend the closer you get to the picture quality in your local cinema. Most projectors can be adjusted to compensate for an awkward room layout and all — excepting CRT, which we’ll come to later — are small enough to sit on a table and can be set up and operated quickly and easily.

Key features to check
There are, however, many things to bear in mind before making a purchase. When testing a projector — which you should always do before parting with your cash — look at fan noise (anything under 30dB is good) which can spoil a quiet movie, the brightness of the projected image (measured in ANSI lumens), and how long the lamp will last. New bulbs are expensive, so a short lamp life could mean extra expense and irritation.
And even though a short-throw lens can cope with a small room, it still needs about two metres between it and the screen or wall to give a decent image. Be sure to look at the throw distance of each projector’s lens and whether it will produce a big enough image in your room, so take down the room’s dimensions and think about where the projector can sit. You may want to permanently install a projector on the ceiling, but regardless of where the projector is, it will need to be some way from the DVD player or TV source, so hiding cables becomes an issue.

Drawbacks
Obvious but true: projectors don’t work in daylight, which is a drawback if blocking out light sources is a problem. The room will need to be as blacked-out as possible, because any ambient light creeping in could negate the contrast ratio specs of your projector, which is just as important as brightness. With low contrast models you will need a total blackout to get a passable picture.
Talking of which, reproduction of black via projectors is often dodgy (as it is with LCDs) unlike on CRT TVs — definitely worth bearing in mind if your genre of choice is horror or for any films with a lot of darkness. As a rule of thumb, the higher the contrast ratio, the better the presentation of black will be.

Don’t forget the screen
Lots of us have white walls, but don’t be tempted to permanently rely on them to take your projections — unless you go for something like Goo, which is effectively light-reflective grey paint that goes straight onto a wall. The importance of a good screen can’t be understated, and as little as $350 can get you a decent screen that does justice to your projector.

Technologies
If you haven’t been scared off, it’s time to choose your technology. The rival technologies — LCD, DLP and CRT — all have their pros and cons.

LCD
Let’s start with liquid crystal display projectors (LCD to you and me), which were originally designed for the computer data presentation market. Starting at around $1,500, this is the entry-level choice for many movie buffs. LCD projectors use an optical system that divides intense lamplight into red, green and blue beams for delivery through three LCD panels. The picture signal is then assessed and the tone of light adjusted on a pixel-by-pixel basis. The beams are then merged and projected onto the screen.
Despite their reputation for bright pictures, great portability and ease of use — as well as the reasonable prices — LCD projectors are prone to certain problems that are common to LCD televisions. As well as the occasional ‘dead’ pixel (relatively uncommon these days, but annoying as it leaves a permanent black spot on the screen), LCD projectors can sometimes deliver unnatural colour tones. What’s more, contrast ratios of low-end LCD projectors can be poor compared with a good DLP or CRT projector (although they’re improving all the time). Although screenburn is not an issue, noise is; a fan is constantly needed to keep the optical components cool — more so than for DLP projectors.
And then there’s the ‘screen door’ effect. The construction of the LCD panel sometimes shows up in the projected picture with projectors that have a low pixel resolution, which makes the action in a film appear to be taking place behind a net or chicken wire pattern. Lamp life is only 1,500 to 3,000hrs for LCD projectors.
So it’s small, light, portable, simple to use and fairly cheap, and despite its origins, LCD projectors do a solid job as a home cinema solution, but with the above flaws at the lower end of the market.

D-ILA
A variant — and what will probably become an upgrade — of LCD is D-ILA (digital direct drive image light amplifier), a technology pioneered by JVC. Made up of groups of pixels that mirror each image dot, it’s a reflective type of LCD that delivers more light. As well as diminishing the chicken wire effect, D-ILA promises better contrast ratios, colour and tone than most LCD projectors.
Additionally, D-ILA is based on a microchip that squeezes 2,048 x 1,536 pixels onto a single 1.3-inch chip, so can deliver high-definition images at their full-spec resolution of 1,920 x 1,080. With high-definition mediums due to go mainstream soon (HD DVDs, Blu-ray discs and, potentially, HDTV), D-ILA could eventually become the de facto LCD projectors of the near future.
That’s unlikely for a while, though, because D-ILA projectors are very expensive and are aimed at businesses and high-end users. Still, it makes sense to make sure that, whatever technology it relies on, your projector is compatible with high definition.

DLP
Newer to the market than LCD but designed largely for home cinema use is DLP (digital light processing). Developed by Texas Instruments, DLP works with mirrors. It relies on a microchip with thousands of tiny tilting mirrors constantly adjusting position to create, in theory, a sharp and fast-reacting picture.
The projector’s lamp then shines through a colour wheel and onto the screen or wall.
In many ways DLP projectors have the same advantages as LCDs. Just as simple to set up and use, also small and light and also great with PC pictures, DLP models can get as low as $2,000 each and don’t suffer from screenburn.
As with LCD, lamp life is only 1,500–3,000hrs and dead mirrors are a possibility, leaving a black spot akin to the problems of dead pixels on LCD projectors. Because there is also a spinning colour wheel, DLP projectors are a little noisier than LCDs.
That unique colour wheel also brings problems unique to DLP projectors. The biggest — but only to some eyes — is the ‘rainbow’ effect, which is when the 300-times-a-second rotation of the colour wheel causes bands of colour to occasionally flash across the screen. For some reason, people with blue eyes, especially, seem to notice the rainbow effect, while others remain completely oblivious to it.
Also note that DLP projectors with four-segment colour wheels are the main rainbow culprits, whereas six-segment wheels are less affected. The ultimate solution is to invest in a three-chip DLP projector (one each for red, green and blue), but as this technology costs upwards of $20,000, the rainbow effect will remain a very distracting anomaly for many for a while yet.
At the other end of the spectrum, DLP’s biggest advantage over LCD projectors is the colour black. DLP delivers much better black levels and a bigger contrast range, although this does depend on the individual models.
Other problems of DLPs can be dotty noise on fast-moving objects and camera pans, and dark areas of an image appearing with grey or green dot crawl on some DLP models. Thankfully, this is becoming rare.

CRT
Another dying breed — at least for the mass market — is CRT or three-tube projectors. Expensive and cumbersome but delivering unbeatable pictures, CRT has fallen foul of the digital age, but if a permanent installation is possible, look no further.
Based on the electron-firing principles of a CRT (cathode ray tube) television, they contain three high-brightness, monochrome tubes. Each tube contains red, green and blue, which are then converged via filters to line up the three component colours and deliver the finished image.
Completely free of digital processing artefacts, that image has fantastic contrast and unbeatable detail, with video-friendly, natural colour tones that only the top-end models in the other technologies can approach. Some CRT models even use a liquid coolant, and are thus silent.
The only noise comes from disgruntled CRT owners, because expenses can spiral. Relatively expensive to purchase in the first instance, CRT projectors are bulky and require a permanent installation. They also suffer from problems that are expensive to fix, including screenburn and poor lamp life; the prohibitive cost of replacing a lamp has left many a CRT dormant for months. Another consideration is the need to regularly check and adjust image alignment between the three colour guns.
Other minor gripes are that CRTs aren’t suited to projecting multimedia images from a PC because the pictures are not as bright as on projectors using DLP or LCD technology, and a CRT’s complex nature can easily confuse novice projectionists.

DLP VS LCD
All round, the tried-and-tested CRT projectors are generally the best quality, but because of their expense and disadvantages the battle for the mass market is between DLP and LCD projectors. A report published by Texas Instruments — who, as the inventor of the DLP technology has a vested interest — purported that DLP projectors were more reliable than LCD models, which it claimed suffered from colour staining after about 4,700hrs. However, the LCD projectors were run continuously and the problems were probably due to overheating, so don’t put too much stock in this.
More important is to look for a number of features on different projector’s specs that will likely improve the image.
Keystone correction is a digital process that straightens the edges of a picture when the projector is not directly in front of the screen, a feature which you shouldn’t underestimate if you have a smallish living room and the projector isn’t going to be permanently ready to use. However, as a digital process, keystone adds additional processing to the final image. To alleviate this, many projectors are now being produced with lenses you can physically move both vertically and horizontally to line up the image.
Progressive scan improves the detail and sharpness of images by showing all the lines of a picture in one go instead of the usual two separate sweeps.
Blank lines in pictures are reduced by Faroudja DCDI, a French digital technology that also makes curved edges look less jagged.
Many projectors use 16:9 widescreen pixel panels, a feature worth looking out for because this produces a sharper, more detailed picture compared with other projectors, which only give widescreen using a reduced portion of a 4:3-ratio panel.

Technology Pros and Cons

LCD

PROS
Easy to set up LCD projectors take just a few minutes to get up and running, and require little technical knowledge
Lack of picture artefacts The lack of a colour wheel does away with the sort of picture artefacts found with DLP
Affordable LCD projectors can be purchased for less than $2,000
No screenburn This is when onscreen logos (such as a channel’s icon) become permanently burnt onto the screen — luckily LCD technology does not suffer from this
Size Although LCD projectors can vary considerably in size, they tend to be small and light. This makes them portable and easy to hide away when not in use
Multimedia friendly LCD’s panel system makes it a winner with PC pictures

CONS
Contrast Although this is improving all the time, even the best LCD projectors tend to only have a contrast ratio of around 1,300:1 — a fraction of what a good DLP or CRT model can manage
Chicken wire effect With many LCD projectors it’s sometimes possible to make out the physical construction of the LCD panel in the picture, so that what you’re watching seems to be taking place behind a fine layer of chicken wire
Colour balance LCD projectors can sometimes find it more difficult to deliver a natural colour palette than rival technologies
Fan noise If anything, LCDs can be even noisier than DLP projectors
Lamp life Many LCD projectors need their lamps changing after 1,500–3,000 hours of use
Dead pixels Although this is a rare problem these days, it’s still possible for an LCD pixel to ‘die’, leaving a permanently dark or bright pixel on the screen

DLP

PROS
Contrast Compared to LCD and LCOS options (though not CRT), DLP can offer much better black level response. The contrast range varies widely between different models though
No screenburn This is when onscreen logos (such as a channel’s icon) become permanently burnt onto the screen — luckily DLP technology does not suffer from this
Size Although DLP projectors can vary considerably in size, they are often very small and light, making them portable and easy to hide away when not in use
Multimedia friendly DLP’s structure makes it just as at home with PC pictures as video
Affordable DLP projectors can be had for under $2,000
Easy to set up You can get most DLP projectors up and running within five minutes

CONS
Rainbow effect The DLP colour wheel means that images can suffer with flashing bands of colour, especially in your peripheral vision. Six-segment colour wheels suffer less with this than four-segment ones, but the only way to completely avoid this is to get a three-chip DLP. These are getting cheaper, but you’ll still struggle to find one for less than 20k
Noise on motion DLP pictures can suffer with dotty trailing picture noise during camera pans or with fast-moving objects
Lamp life Many DLP projectors need to have their lamps changed after 1,500–3,000 hours of use
Operating noise DLP projectors use fans to keep their lamps cool — and these can be noisy. And there’s the spinning colour wheel. The total extent of this noise varies considerably from projector to projector
Dead pixels Although relatively rare these days, it’s possible for an individual DLP mirror to ‘die’, leaving you with a permanently dark or bright pixel on the screen
Dot crawl Some DLP models struggle to keep stop green or grey dot crawl from appearing over dark areas of the picture. This is a much less common problem than it used to be

CRT

PROS
Contrast CRT projectors consistently deliver the most natural, cinematic-looking black level of any projection system
Lack of artefacts CRT suffers with none of the buzzing noise or chicken wire of rival technologies
Colour tone It usually takes a pretty high-end version of a rival projection technology to deliver colours as natural as those achievable on even a bog-standard CRT projector
Quiet running Some CRT projectors use a liquid coolant around their lenses to eliminate the need for noisy cooling fans
Resolution CRT’s lack of any sort of ‘panel’ in producing its pictures means it can actually deliver more nuanced, detailed video pictures than any other front-projection system

CONS
Requires permanent installation
Size CRT projectors tend to be bulky
Brightness CRT projectors don’t generally deliver pictures as brightly other technologies — which means many aren’t especially well suited to PC use
Complex Because of the emphasis on professional installation, some CRT projectors can initially seem complicated to novice users
Screenburn This is when onscreen logos (such as a channel’s icon) become permanently burnt onto the screen
Expensive The sheer amount of engineering and materials that go into CRT projectors makes them more costly than other projection technology. The cost of replacing CRT lamps can be prohibitive

D-ILA/LCoS

PROS
Resolution Since each pixel’s driver electronics are positioned directly underneath it, more pixels can be fitted into the optical array. In fact, LCoS — or more specifically, D-ILA — was actually invented for the US military in response to a need for more finely detailed display devices
No chicken wire effect
Brightness The lack of space between pixels means there are fewer dull areas in the picture and less wastage of light from the lamp
Colour LCoS colours manage to combine vibrancy with a natural video tone
No screenburn
No rainbow effect No colour wheel means no rainbow effect

CONS
Expensive Still relatively new to the projection scene, LCoS and D-ILA systems are expensive
Contrast At the moment LCoS/D-ILA projectors tend to lack contrast, especially compared to CRT and DLP rivals. This will doubtless improve, however
Availability Still a new technology, there are currently very few commercial front-projectors available in this country that use LCoS or D-ILA. That’s expected to change, however.

Connections
Just like a bad businessperson, a poorly connected projector is worthless, so carefully consult our connections chart presented here to make sure your purchase is compatible with both your current equipment and future developments.
With developments in high definition on the horizon, there’s never been a better time to invest in a projector and go super-size.

Component video
Red, green and blue parts of the picture are delivered separately through three cables to reduce interference. Essential for quality images and progressive scan pictures

DVI/HDMI
Cuts out the digital-to-analogue conversions when transmitting from a HDMI/DVI-equipped source, and isbe able to accept high-def images from Blu-ray, HD-DVD and HDTV— vital.

Composite video
Delivered via Scart or a single phono cable and produces noisy pictures. One to avoid

S-video
Giving reasonable pictures (but inferior to RGB, HDMI or component), S-video is delivered via Scart or, more usually on projectors, through a four-pin lead

15-pin D-sub VGA input
Surf the internet like never before. Used on most projectors for attaching a PC

USB
Aimed more at businesspeople carrying presentations and JPEGS on memory sticks, USBs are nevertheless useful for boring friends with your holiday pictures

12V trigger output
Useful if you want to hook up something fancy to your projector, like an automatic drop-down screen

Scart
Although rare on projectors, Scart connections are great for connecting existing equipment. And though they can accept composite, S-video and RGB signals, only the latter approaches the quality of component video

Shopping tips
One of the best tactics when hunting for the ultimate projector in your budget range is to take a favourite DVD along and watch specific scenes you know well on each model. Fast-moving scenes with a lot of action and quick camera panning will show up any rainbow effect on a DLP, while films with lots of darkness will reveal the level of a model’s contrast ratio and its reproduction of black.
Just remember not to be swayed too much by the sound system in any particular dealer’s demo room. They are trying to sell you the whole home cinema experience, not just the projector, and it’s a fact that the images actually look better to the human brain if they are backed up by music (that’s why computer games are stuffed with music). So for the purest test of a projector, turn the sound off and concentrate purely on the image: that’s what you’re paying for.
What you don’t want to fork out for are distracting rainbows that will spoil your enjoyment of a film, so while in your dealer’s demo room, shake your head from side to side when watching a projector’s output. It’s also a good test of a dealer’s knowledge of projectors, because if they look at your demented head-shaking with a worried look, they obviously don’t know what they are selling and you should leave the shop immediately.

Getting what you pay for
Projector prices go from as little as $1,200, up to tens of thousands of dollars. Which raises questions as to exactly what stepping up to the next price bracket gets you …

Under $1,700
Currently projectors this cheap are almost always designed primarily as business or school presentation devices. And as such they tend to prioritise portability and extreme ease of setup, as well as favouring PCs in both their connectivity and, more pertinently, their picture attributes. Pictures will almost always be made using the generally PC-friendly LCD system, favour extreme brightness levels over contrast, and have their white balances set to suit the colour tone of PCs, not video. This latter situation can leave skin tones, for instance, looking a bit green.
You will also commonly find projectors as cheap as this using pretty low native resolutions (eg, VGA, SVGA) that are configured in the 4:3 aspect ratio rather than the more movie-friendly 16:9 widescreen aspect ratio.
Finally, you can expect cheap and cheerful build quality, including fairly low-grade lenses, and usually pretty extreme levels of cooling fan noise.

Around $2,000
While some cheaper projectors can certainly be used for home cinema, at the moment it’s only really at the $2,000-or-so level that you start to find models designed from the ground up to be home cinema friendly.
DLP technology is increasingly regarded as the superior home cinema option to LCD, and it’s at around $2,000 that the first DLP models appear.
Whether you go for an LCD or DLP model, you can generally — though not exclusively — expect fairly low-resolution native chipsets. But this time you can certainly find some with a native widescreen aspect ratio.
LCD models will still probably be at least as interested in PC presentations’ use as they are in video, though, again potentially finding brightness dominating over contrast, unnatural white balances, and little if any attempt to suppress LCD’s chicken wire effect.
In the DLP world, you can expect single chip models where colours are created using a colour wheel. This colour wheel will generally be a four-segment, four-speed affair, meaning that you will likely see the rainbow effect.
This colour wheel can also produce dotty fizzing (excessive picture noise) over motion while the likelihood that a $2,000 model will have used an older or less well-specified DLP chipset could give you less contrast and more green, dotty noise over dark picture areas than you’ll find with higher rent models. You’ll still almost always get more contrast out of a $2,000 DLP projector than a $2,000 LCD one, though — but an LCD one will generally serve up much greater brightness.
$2,000 projectors will still tend to have fairly low-spec lenses, and run noisily.
In terms of setup, $2,000 projectors will favour simplicity and portability, as they’re generally focused on the fairly casual user who just gets their projector in and out of cupboards as and when they want it.

$3,000
While there are some truly excellent models for under $3,000 (not least Screenplay’s new 4805), this is where things start to get serious for the home cinema user. And tellingly these days it’s the point where LCD projectors start to become much less common than DLP models.
There are still some LCD models around, though, and they’re usually by now delivering much better contrast ranges, greater flexibility with regard to white balances, higher resolution, native widescreen LCD panels, and lots more video-friendly inputs. We would also expect an LCD projector for this money to have some quite sophisticated scaling technology, such as Faroudja’s acclaimed DCDi system, and possibly some in-lens or processing system for tackling LCD’s chicken wire problem.
On the DLP side, more resolution is again to be expected, as well as native 16:9 chipsets and better colour wheels that can spin more flexibly — eg, six-speed — and have more colour segments to reduce motion tizzing and the rainbow effect.
A higher level of DLP chipset could well be on hand too. We haven’t the space to go over all the relative strengths and weaknesses of the different Texas Instruments DLP chipsets out there, but basically higher quality, higher value ones will offer improved mirror tilting, better suppression of the light from the metal behind the mirrors, smaller holes in the centre of each mirror and so on to deliver less noise and much-improved contrasts.

$8,000
By the time you reach this price point, LCD has practically disappeared from the equation, leaving us free to focus on DLP. By now you can expect really high-end, high-resolution, widescreen DLP chipsets as standard; more flexibility in how you can adjust the way the picture looks; refinements to the colour wheel; considerably more efficient lamps able to deliver higher brightnesses; and most importantly of all, truly sophisticated scaling technology to ensure that all levels of source material are ‘mapped’ onto the native DLP panels more accurately and with less noise and artefacting.
Improvements in basic build quality should find some seriously fine lenses too, while you should also experience less fan noise thanks to higher-quality bodywork and fan motors.
Eight-thousand-dollar projectors may not be quite as easy to set up or as portable as cheaper models, but this is only because they’re generally expected to be set up just once and left in a permanent installation carefully calibrated to get the most out of their much-improved specs.
Finally, for this money you can generally find a greater emphasis on new, high-end digital video inputs, and more lens flexibility to support potentially huge screen sizes.

$17,000
By now LCD has disappeared — but curiously, DLP doesn’t have the market to itself. As well as the occasional appearance of one-off options using new technologies, like D-ILA, by this price there are also a handful of models around using traditional CRT technology. And as long as you can live with a lack of brightness and permanent installations whereby your projector can’t be moved so much as a centimetre once it’s been installed, CRT projectors can reward you with stunning levels of contrast and perfect colour tones — though perhaps not the definition and brightness of a DLP model.
DLP projectors at $17k (should!) justify their prices by using the absolute latest Texas Instrument chipsets, state-of-the-art colour wheel and lamp power systems, endless flexibility in terms of how you can make the picture look and room size/setup, premium grade lens arrangements (often with different lens options available to suit the user), and the most sophisticated scaling systems on the market. Not to mention uncompromising connectivity and internal build quality to reduce the potential for electronic interference or inefficient light spillage.
While one or two $8,000 models can give some $17,000 models a run for their money using moderate screen sizes, truly excellent $17,000-plus models can definitely look more noiseless, sharp and filmic on a large screen than their cheaper counterparts.

$30,000 plus
These days this sector of the projection market is defined by one or two high-end CRT models (defined by more powerful and better controlled lamps and oodles of image processing), and an emerging breed of three-chip DLP projectors. These DLP bad boys use a separate DLP chipset for the red, green and blue elements of the picture, avoiding the need for a colour wheel and thus eliminating all traces of the rainbow effect and fizzing over motion. And boy, do they work well …