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Digital TVs

written by Mike Shea on 21 November 1999

The following article has now been outdated significantly. It remains here for archival and research purposes only. Many of the views outlined here are now out of date and may have changed. Please read Digital TV Part 2 for a newer look at home theater monitors.

Ever since I first saw a 16x9 TV I knew I wanted one. I am primarily a movie watcher, and ever since I got my first DVD I knew it was the only way to watch movies at home. Personally, I could give a damn about watching the Packers in high definition, movies are my primary interest. Because of this, HDTVs are not my primary target, Widescreen displays are and DTVs are the easiest way for me to get a widescreen display. With the proliferation of HDTV growing and DVD players now outputting multiscan signals, picking a good DTV is the key to the perfect home theater.

This article is designed to stand the tests of time. It will go over all the important information about digital displays for those looking for the ultimate home theater monitor. In order to keep the information accurate, I will not be getting into individual products except for the current best buys.

A Quick Lesson on 16x9:

Movies are primarily displayed in two native sizes. These are 1.85 to 1 and 2.35 to 1. A 16x9 screen can display a 1.85 to 1 over the full screen and a 2.35 to 1 is shown with small bars at the top and bottom. In contrast, a 4x3 display doesn't come close to fitting the display of a theatrical aspect ratio film, making a widescreen display a necessity. The best way to utilize a widescreen display is with a 16x9 enhanced DVD (also called an Anamorphic DVD). Here is an excellent article on the basics of 16x9 enhanced DVDs called The Ultimate Guide to Anamorphic DVD for Dummies and a detailed report on 16x9 enhanced DVDs by Cybertheater.

Ideal Screen Size:

I have heard a lot of different opinions on screen size, so I am going to throw up mine. I checked the THX homepage for the specs on the smallest field of vision a screen should take up for a viewer and it came out to 26 degrees to 36 degrees. Doing some quick math we can come up with the following formula:

(Distance (inches) = Screen Diagonal size (inches) / .61)
or
(Diagonal Size = Distance * .61)

It may seem big, but when you consider that this is for a movie theater sized screen and that even this is the minimum you should have, it doesn't seem that outragous. Here is an even easier rule of thumb:

.5 * distance = Diagonal
or
2 x Diagonal = Distance

This formula does not take image quality into account. For anything larger than 40" you will do better with at least a line doubler. Anything larger than 72" might need more than that. Also keep in mind, this is for a 16:9 set, not a 4:3, but I don't think anyone trying to recreate a true THX theater in their home would do a 4:3 set. Basically, here is the easiest formula:

Get the biggest screen you can.

DTV vs HDTV:

Here's a quick and dirty lesson on DTV and HDTV. The resolution of digital television (DTV) is 480 progressive (480p). This means that the set can display all 480 lines per 1/60th of a second with no interlacing. A standard NTSC set (like every one in America) is 480 interlaced (480i). DVDs are recorded at 480p, but standard DVD players output them at 480i. HDTV is one step up from DTV. It has either 1080i or 720p as standard native resolutions. When a decoder gets a signal it can't show natively it either down converts it to 480p or "upconverts" it to whatever it's max native resolution is, usually losing some of the material in the process. Many HDTV sets are 1080i native, but more are starting to come out at 720p. Also, most current HDTV sets cannot display the full 1920 vertical resolution of the 1080i signal. It is debatable whether this is a real problem or not. Basically the best way to see the full power of HDTV is with a 9" CRT front projector which can run at least $15,000. Here is a breakdown of the different signals and resolutions.

720 Progressive or 1080 interlaced?

These two resolutions are the main high definiton standards. According to Joe Kane, ex-Imagery Science Foundation guru and consultant at Widescreen Review, the 720P signal is superior to 1080i since no interlace artifacts are present. Whether this should affect which one you buy is your decision, but it certainly should be considered when you make your choice. Here is an article on Runco's homepage discussing Joe Kane's take on Progressive Scan. Here are some conclusions about HDTV.

It's Not the Size, It's the Frequency:

With CRT projectors and tube based rear projection TVs the limiting factor is the Horizontal Scan Rate. The following chart shows the different signals, their resolution and their horizontal scan rate.

Display Type Resolution Signal Type Horizontal Scan Rate
NTSC 640x480 Interlaced 15.75Khz
DVD / DTV 720x480 Progressive 31.5Khz
1080i HDTV 1920x1080 Interlaced 33.75Khz
720P HDTV 1280x720 Progressive 45Khz
Signal of the Gods 1920x1080 Progressive 67.5Khz

Current console HDTV sets are limited mainly to the 1080i scanning frequency and limit their incoming signals to 15.75 for NTSC, 31.5 for 480P and 33.75 for 1080i HDTV. Only multi frequency displays can do any or all of the above. This is limited mainly to front CRT projectors. For a more detailed look at HD compatibility take a look at Cybertheater's HD front projector guide. Basically since 1080i requires less of a scanning frequency, more producers and manufacturers have embraced it even though 720p is more compatible with future products and looks better.

What Mikey wants for Christmas:

Based on the above criteria, I have come up with the following guidelines for my ideal display device:

Line Doubled is NOT Progressive

A lot of monitors are now coming out as "progressive" displays, but in fact have a built in line doubler. Now some external line multipliers are very good, but some are quite costly ($3000 to $20,000). Most of the high definiton sets I have seen with built in line doublers are not quite up to speed. There are some inexpensive external doublers like the DIVO iscan. Here is a review from Secrets of Home Theater of the iscan. Right now, to be truly progressive, you need a true progressive source (like a progressive DVD player or 720P HDTV decoder).

Now that we have covered a little about the features of digital televisions, we will take a look at some of the current trends in displays and sources. Keep in mind that it is difficult to keep this section up to date so it may not have every good display currently available.

Progressive DVD Players Now Available:

Finally the long awaited progressive DVD players have started to hit the shelves. Panasonic's DVD-H1000 ($3000!) and Toshiba's 5109 and 9100 have been released after many months of battling security issues with Hollywood suits. These players are compatible with any component progressive input on digital displays. While currently no hardware mpeg decoder is able to output a true 720x480 progressive 24 frame signal (the native signal of a DVD) these players have the equivalent of a digital line doubler that reconstructs the frames before they are turned into an analog signal. For smaller displays (up to 65") it is the cleanest picture you can get from DVDs.

Toshiba's DTV lineup:

Toshiba's DTV division has also released three rear projection sets that are capable of 1080i HDTV and 480 progressive DVD sources. The sets range in size with 40", 56" and 65" models and run in the area of $2500, $4500 and $6500 respectively.

Mitsubishi's DTV department has released a new line of HDTV sets that include the 480p progressive inputs required for progressive DVD. They also released the DD-6000 progressive DVD player. Unfortunatly this combination will not display non 16x9 enhanced DVDs in the progressive mode. I have seen this combination in action and it is extremly clean and accurate.

Princeton's 720P Reference Monitor

Princeton Graphics has released a monitor that is currently the favorite of Joe Kane the above DTV evangalist. This monitor is one of the only displays that can display a true 720P source. The monitor is called the Princeton AF3.0HD HDTV. It includes both NTSC and HDTV component input, RGB via VGA input, max resolution of 1024x768, a 16x9 aspect ratio and can decode any of the current HDTV standard resolutions. The down sides are the size (30" viewable screen). The price is reasonable for a set of this quality at around $4000. In an article with Joe Kane in issue 33 of Widescreen Review, Joe Kane stated that this monitor paired with a RKR DVD-ROM system gave a true 1024x768 upscaled picture that rivaled the best in the world. It is currently his standard which is saying a lot. Princeton has put out word that it is going to be releasing a 34" version of this set soon.

Sony does 16x9 on a 4x3!

Sony recently came out with a new line of their flat screened XBR 250 WEGA TVs (pronounced vega). These new sets which come in 32" to 36" include a one button squeeze that allows you to watch 16x9 enhanced DVDs without downconversion. The screen is a little small and much of your screen is wasted if you mainly watch letterbox material, but it is one of the best pictures you can get for that price. Unfortunatly the cost of these sets, $2000 to $2500, might be better spent on a native 16x9 display.

Predictions of the Future.

My gut feeling right now is that digital projectors will be the future of home theater displays for the middle ground consumer spending between $4000 and $10,000. Currently they are limited in their black level, but their resolutions and HDTV compatibility are getting better and better. Keep an eye out for Texas Instruments to come out with a single chip DLP projector in a native widescreen aspect ratio. These digital projectors will offer the best and biggest pictures for less than $5000. Here is a summary?

My Recommendations

Ok, so right now what are my recommendations. For less than $2000 your best bet is to stick with an NTSC set. They are making excellent tube TVs down to 27" and you really can't expect anything larger than 36" for this price. Make sure it has s-video or component video for DVD players and future HDTV decoders. In the $2000 to $4000 I would go with the Toshiba TW40X81. It his HDTV compatible, can do progressive DVD (assuming we get a player) and is reasonably priced (about $2500). At $4000 to $10,000 I would have to go with the Sony VPL-10HT. This upgraded VPL-W400Q has it all of the requirements except for a deep black for around $6000. At $10,000 and up, CRT projectors are still the king. I particularly like the Dwin and Sony projectors which run around $10,000 to $15,000 and are fully HD compatible with great abilities to line double NTSC video. This is still the only way to get that great CRT picture with true blacks, great contrast and perfect images on a large screen. The only draw back is the high maintenance and high cost. Here is the breakdown:

  • Direct View HDTVs and Widescreen Digital RPTVs guide
  • The Big Picture (including Sony VPL-W400Q forum)
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