Avi Greengart is the Research Director for Consumer Devices at Current Analysis (Mobile Phones, Connected Devices, and Digital Home). He also regularly writes for Slashgear, sporadically blogs at Home Theater View and Tweets far too often as @greengartAvi's expertise lies in understanding consumer electronics marketing, consumer behavior, and technology adoption patterns: where new technologies meet the mass market. 



Avi Greengart is an expert on the convergence of technology and entertainment: video, audio, computing, and wireless, how these are coming together, and what's likely to survive long enough to make a difference in your life.

Column #24 (12/31/2007)

1. Help With DVD Hookup, 2. Can You Wring the Resolution Out of HDTV?

Question #1 of 2 this week:

I have a DVD player with 5.1 channel output. It has RCA connections for the outputs, but it also has an optical connection. I want to get a surround stereo system. I live in a condo (so I am not blasting it too loud) and my room isn't that big. In addition, I don't plan to spend that much money. I saw some systems "in a box" (as you have put it in an earlier column) that had RCA inputs for the various speakers. However, I saw one that had an optical input. The product info says that it has a digital decoder (I think that was the term). It does not have the RCA inputs. Is that as good as using RCA cables for each output-input? Is it better or worse? Why?

AskAvi replies:

All DVD players have at least one digital 5.1 channel output (either an optical "Toslink" connection and/or a coaxial cable connection). If you have a receiver with Dolby Digital decoding (nearly all new receivers do), use a digital connection (when given a choice, I prefer the optical connection), and let your receiver do the decoding work. This will get you the best sound.

Some DVD players have a Dolby Digital decoder built in, and analog 5.1 outputs (6 RCA jacks - front left, front right, front center, surround left, surround right, and subwoofer). The only time you'd use this is if you bought a receiver a few years ago that was "Dolby Digital Ready" - it doesn't have a decoder, but does have 5.1 analog inputs. Even in this case, you should consider upgrading to a new receiver, because you'll usually get much better bass management by letting the receiver do the decoding.

All DVD players have analog stereo out (left and right RCA jacks). If you don't have a receiver at all, you can hook up the DVD player to the TV using the analog stereo out. However, you should seriously consider buying a receiver and a good set of home theater speakers, or at least a "home theater in a box." The difference between dynamic multi-channel soundtracks vs. fuzzy stereo from your TV's built in speakers is NOT subtle. (Unless, of course, you only watch foreign and classic films with mono soundtracks. Then you won't notice any difference.)


Question #2 of 2 this week:

I'm confused about the resolution of the InFocus LS110 (as well as other HDTV compatible DLPs or HDTV-ready TVs).  For watching DVD, this is not an issue.  For HDTV, it claimed that it is 1080i compatible.  But how does a 848 X 480 chip display 1080 lines, or is this something that only XGA DLP such as the Sharp z9000 can do?  Currently I'm considering either this unit or a HDTV-compatible ~50 inch big screen TV, to replace my 7-year old Pioneer 53 inch big screen TV.  The latter is a LOT more bulky but gives me the impression that it can "display" HDTV signal (1080i).  Is this just hype?  Cost wise, the latter has a slight edge.

AskAvi replies:

Aside from CRTs with 9" electron guns (found in front projectors starting at $20,000), there are no consumer devices out there that can display 1080x1920i (1080i) with full resolution today - even the Sharp XV-Z9000 digital front projector scales images down from 1080i to it's native panel size, 720x1280. All fixed pixel devices (a TV or projector based on a chip of some kind, not an electron gun) have a specific resolution they can output, and all other resolutions you feed them get modified to fit the available number of pixels. Also, fixed pixel displays are progressive by nature - this means that the signal first has to be converted to progressive scan ("deinterlacing"), but it also means that in order to create a fixed pixel device that can display 1080i in full resolution, it will have to be able to display 1080p. That's a lot of pixels to put on one chip - 2,073,600 to be exact! - and nobody has done that yet for the home theater or business presentation market.


The InFocus ScreenPlay (LS110) will scale 1080i down to 480x848p, the number of mirrors on it's DLP chip. This will still look better than regular TV (a lot better), but it's no longer true high definition. Most 50" big screen televisions are based on 7" CRTs; they also can't resolve full 1080i. How much better - or worse - HDTV you'll get out of one of those vs. the LS110 depends on which specific television model you're comparing it to. A few will be a little better (I've seen specs as high as 960i, though few units can actually pull that off), but perhaps more important for a form of television, all big screen TVs can be watched with the lights on.


But if you mostly plan to watch DVDs in a dark room, no big screen TV will hold a candle to a front projector for sheer impact. With a projector, you can easily have an 86" 16:9 image - that's much, much bigger than a 50" 16:9 image. With the larger image, you can see all the nuances of the actors' faces... tell how good the DVD transfer is... and become more involved in the movie experience.



16:9 - refers to the rectangular shape of HDTV televisions. For a better overview, see Column #9.

1080i - one of the U.S. high definition TV standards. With 1080 horizontal and 1920 vertical lines of resolution, there's a lot of image information. However, the "i" stands for "interlaced," meaning that the TV draws every even line and then comes back and draws every odd line, the same technique used in traditional TV. In contrast, a computer draws all the lines in each pass; this is called progressive scan. Most HDTV-compatible displays can also display 480 x 720 progressive scan images, called "480p."

DLP Digital Light Processing a technology popularized by Texas Instruments that bounces light from an expensive light bulb off of a chip. Most consumer and business DLP front projectors and big screen TVs use a single chip, which is covered with hundreds of thousands of tiny mirrors. The light then passes through a rapidly spinning color wheel, through a lens, out into the air, and onto your screen.

XGA - a computer term referring to a device capable of 1024x768 resolution.

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2001, 2002 Avi Greengart