Digital TV part 2

written by Mike Shea on 14 April 2002

Thanksgiving day, the dysfunctional family is all packed into my 600 square foot apartment, wondering how anyone can live with two chairs, seventy eight spoons but only one knife. Fitting the mood, I decide to put on my brand new copy of the Godfather. I turn on the trusty VPL 400Q projector and....and.....nothing. Dead, like Moe Green with a bullet in the eye. The projector is just over two years old but deader than Sonny in the toll plaza. Now the projector sits on the floor like a severed horses head while I stewed. After wallowing in self pity for the last five months, I decided it is time to reevaluate the monitor in my reference screening room. I wrote a couple of articles on Digital TV before, both pointing to front projection systems. This time, however, I would come up with a list of criteria for my ideal reference monitor. This article covers these criteria, and discusses some newer trends in Digital TV.

New Criteria for DTV:

Some things are important, and some are not. This is as true with Digital TV as it is with anything else. It is important when deciding on a new display to take in all the data and match it against a list of criteria that we have for the ideal display. After living with an overhead projector for the last two years, and a CRT based display before that, I have come up with the following list of criteria for my own ideal DTV.

Noise Free: One of my main complaints with the Sony VPL400Q LCD projector was the fan noise. While most newer projectors have dropped their fan noise to 30dbs, barely perceptable with any other audio signals in the air, only CRTs offer true noiseless operation. There is no active cooling for RPTVs and some front projection systems are even fan-free. Whatever display is considered for a quality home theater, it must be almost completly silent.

Deep Blacks: Another major problem with LCD / DLP projectors is their black level. Because of the way these two systems shine, ambient light bleeds through creating blacks that are really dark grey. This hurts overall contrast and, for darker scenes in movies, makes it harder to separate details within darkness. CRT based displays have no problem displaying very deep blacks. Home Theater based digital projection systems now have cinema modes that supposedly improve black levels, but while they help, they aren't perfect.

Big Screen: In order to properly capture the attention of the viewer, a big screen is imperative. An original equasion I worked with was that the screen diagnal measurement should be 1/2 of the distance you are sitting from the set. Thus if you sit eight feet away, your screen should be no smaller than 48". This is a minimum size, the bigger the screen the better. The following is a THX guideline for theater viewing angles:

The optimum audience viewing angle for the Cinemascope image (2.35:1) from the screen to the farthest seat in the auditorium is 36 degrees with 26 degress as the aceptable minimum. (Applying Dolby's recommended viewing angle using the screen to farthest seat measurement results in a viewing angle of approximately 31 degrees.)

That is a minimum viewing angle for the worst seats in the house, a larger viewing angle, perhaps at 50 degrees, is preferred.

Widescreen: Almost 100% of current DVDs are not only widescreen but also 16x9 enhanced. Any display for a quality home theater system must have a native 16x9 display. This allows DVDs to be displayed at their maximum resolution of 720x480.

Displays Progressive DVD at 480p: Most displays have picked 1080i as their HDTV standard definition. Only LCD displays are able to easily display 720p signals. For DVD viewing, a home theater monitor should be capable of displaying a 480p signal from a progressive DVD source without converting the signal to a native resolution. Since all digital displays will convert the input to their native resolution, they are not subject to this restriction. They should, however, have a VGA input that accepts a signal at it's native resolution.

Under $4000: Current widescreen monitor prices have fallen quite a bit in the last few years. High quality monitors can be easily purchased for under $4000.

5 Year Lifespan: With the short lifespan of the 400Q, I have become sensative to the longevity of a solid monitor. A good display should last at least 5 years but ideally 10. This doesn't mean that the display will be able to handle every possible standard for the next 10 years, but it should perform at an optimum level, providing a good picture, for 10 years. A good warrenty for at least 5 years is definitely recommended for any high end display. Picking a technology that has been proven over time is also important. This points towards CRT based displays as opposed to newer technologies like LCD or DLP.

Analog Is In: Pulitzer Essayist, Roger Ebert, recently wrote about his distain for the new digital projector technologies. Simply put, they are inferior to traditional celluoid film. He even mentions a new 48 FPS process that improves the clarity of movies well beyond that which can be captured via digital.

The same is true for our home theater systems. I have lived with a digital projector for just over two years. It was noisy, not too clear and lacked the depth of black that one can get from analog tubes. Computer screens have continued to improve resolutions without ever turning to digital displays or digital signals. On the monitor where I type this now, I have watched DVDs scaled up to 1080p with only a 21" screen.

While the marketing guys would have you believe that anything with the word Digital on it is better than ever before, analog CRT based displays still offer the highest quality picture, the highest resolution and the longest lifespan. Don't get caught thinking that digital is better. That is just a marketing way to revitalize the industry, nothing more.

CRT vs LCD / DLP: Keeping it in mind that CRTs still have a lot going for them, one should spend some time to compare digital displays like LCD and DLP projectors to traditional CRTs. Here is a breakout of the advantages and disadvantages of both display types:

CRT Advantages

CRT Disadvantages

Digital advantages

Digital Disadvantages

DVI and HDCP: A recent article on DVI and High Definition Copy Protection standards from the MPAA has many new display shoppers worried. A new standard in digital video signals being sent through a copy protection system could make all current HDTV sets obsolete. As new formats for High Definition DVDs, video tapes, and other HD signals become available, this new standard could be the only authorized method for transfer. While many HDTV sets offer little protection from this new standard, Mitsubishi offers "The Promise" which allows them to upgrade current HD sets to new standards as they become available. While they have not picked out DVI/HDCP yet in writing, this is the best oppertunity available for current displays to support new standards. Only time will tell how these standards are received by DVD production studios, consumer electronic manufacturers and the public.

Conclusion Digital TV is an industry still very new to the public. While HD standards have been around for well over 10 years, it takes a long time for these standards to become commonplace for the consumer marketplace. Now, HDTV is known but hardly supported by most consumers. While the price of HDTV has been cut in half in the last three years, the price is still far outside the scope of most consumers. For the film enthusiasts out there, the new breed of HDTV displays offers us a great variety in high quality displays. While new technologies are being released each day, these new technologies often show us the strengths of the old ones.

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