Category: Product Reviews

Useful Gadgets: Optoma ML300 LED Projector – Pete Putman

Optoma’s ML300 is but one of many LED-powered projectors that have come to market in the past few years. I haven’t paid a lot of attention to this category, because I think that any projectors rated at 100 lumens or lower will be killed off by the increasing use of tablets for small group presentations.


Projectors in the 100 – 500 lumens category are perhaps a bit more secure, provided they are compact enough and idiot-proof. This category, which Pacific Media Associates has labeled ‘new era’ projectors, is distinguished by small, lightweight form factors and solid-state (LED) light engines.

The ML300 is a 'looker' for certain.


Optoma’s ML300 falls right into the middle of that group. The factory brightness rating is 300 lumens in ‘bright’ mode, and the projector barely tips the scales at 1.4 pounds.


Think about that for a moment: back in 1994, Hitachi introduced a 500-lumen LCD projector that weighed 30 pounds, or twenty times as much as the ML300. My old 160-pound Sony CRT projector, also vintage mid-1990s and which used 7” tubes, could barely hit 200 lumens when calibrated.


Along comes this little bugger, which has about the same resolution (1280×800 pixels native on a single DLP chip), doesn’t require any convergence, and supports both analog and digital input signals. Given how closely I follow the world of display technology, not much really impresses me these days – but the ML300 does. (Along with my Nikon CoolPix 8200 16MP camera, but that’s another story!)

Small enough for you?




There isn’t much to the ML300. It has a fixed-focal length lens (1.5:1 projection ratio), which (coincidentally) was the projection ratio of my old Sony projector. That means you can light up an 80”’ diagonal screen with a projection throw of 101 inches, or about eight and a half feet. A small elevating leg is all you’ll have to tilt the projector, which has a positive image offset and auto keystone correction.


In addition to being lightweight, the projector is also quite small, measuring 7.2” wide by 4.4” deep and 18” tall. The light engine is a 3-LED design that presents red, green, and blue sequentially to the WXGA imaging chip. It uses a bit of power – 90 watts peak, when the LEDs are run at full brightness – but those same LEDs should be good for 20,000 hours of operation before half-brightness.


Input connections are limited, but should encompass what you’ll need. On the side panel, you’ll find a full-size VGA connector (really an anachronism in 2012), a mini HDMI jack, an AV connector for composite video and stereo audio input (yes, there is a built-in 2 watt speaker), and a micro USB port for DisplayLink operation (display over USB).


On the rear panel, next to the power on/off button, Optoma has provided a microSD card slot for direct playback of files from memory cards, an analog audio output connector that has a headphone icon next to it, and a full-sized USB connector for flash cards. Use this port to view JPEGs or play back a Powerpoint show file. Not the usual connector complement you are used to, but hey – it’s 2012! (Get with the program!)

Here are the side input connectors.

And here's what the back side looks like.




A projector this small can’t have room for a power supply, so you’ll need to hook up the laptop-style external ‘brick’ supply. Push that rear-panel power button to get things started, and look for the credit card-sized remote control to change inputs and cycle through menu settings.


The HOME menu brings up five choices – Video, Audio, Photo, Input, Office Viewer, and Settings. In Video mode, you’ll see a list of any available video clips from memory cards. (Did I mention that the projector has 1.4 GB of internal storage available?)  The projector will cycle through an external USB flash drive, external microSD card, and then internal memory to search for and play back files.


Video files will be listed with a small thumbnail, while audio files are identified by filename only. JPEG photos show up with thumbnails for easier selection. You can also sequence your photos automatically in a slide show.


The INPUT menu lets you directly access any of the connections and slots. A small picture of each appears to ensure you don’t get mixed up. Wanna go wireless? Optoma offers a WiFi dongle for the ML300 as an accessory and you can access it too from the INPUT menu. As far as playback formats, the ML300 natively supports Powerpoint, Word, Excel, Acrobat (PDF) and bitmap (.BMP) in addition to JPEG.


The SETTING menu breaks down into Video Setting, Audio Setting, Display Setting, Slideshow, and System sub menus. In Display Setting mode, you can adjust LED brightness four ways (Bright, Cinema, Photo, and PC), select between Extended (full) color gamut and Standard (close to NTSC/BT.709), cycle between four different aspect ratios (4:3, 16:9, 16:10, Auto), choose one of four gamma presets (Presentation, Movie, Bright, and Standard), and select the projected image orientation (normal/inverted/ceiling/table).


I should add that in my tests, I could not get my color gamut choices to stick once they were selected. And you won’t find any ‘save’ button or prompt after you make your image adjustments. Every time I selected Standard color gamut (and you’ll see why momentarily) and cycled back to the HDMI input, the projector defaulted to Extended color mode. I could only force the Standard mode by using the analog VGA input.


In fact, the entire menu is a bit slow to use and the IR remote isn’t very responsive. You’ll have better results using the manual buttons to make your selections, but you may get confused (as I did) entering and backing out of sub-menus. I’d like to see Optoma put some more thought into making the menu more logical to navigate, along with improving the response of the IR remote.


Believe it or now, the ML300 also supports 3D playback using DLP Link, but the input signal must be in the 1024×768 (XGA) format @ 120 Hz refresh rate only – no 720p 0r 1080p 3D formats will be recognized.




Right now, you’re probably thinking, “How good can the image quality possibly be from that little pipsqueak?”  The answer: Better than you and I could have imagined. In fact, the ML300 produces images that are every bit as good as my old tuned-up Sony CRT, and I got these images with about 1/100th of the effort.


Is the color perfect? No, but it’s very close. How about gamma? Impressive for a projector in this price and size class. Black levels? Eh, they could be lower. Contrast? Not bad; could be a little higher.

Here's the gamma curve for the HDMI input in Movie mode - about 2.2.


Let’s start with brightness. After what limited calibration I could do (almost none), I measured brightness at 152 ANSI lumens in Movie mode. That number increased to 173 ANSI lumens in Photo mode, then jumped again to 198 ANSI lumens in PC mode. Flat-out brightness was measured at 232 ANSI lumens in Bright mode, a number my 7” CRT would be hard-pressed to equal.


Brightness uniformity was excellent at 85% to the average corner and 70% to the worst corner. I’ve tested conventional DLP projectors that can’t match those numbers, nor can they match the maximum color temperature shift across the ML300’s full white screen (314K).


Contrast measurements were decent, clocking in at 244:1 ANSI in Movie mode with peak intra-scene contrast at 342:1. A 50/50 contrast window yielded a 313:1 reading, while sequential (full black to full white) contrast was logged in the books at 373:1. Again, all numbers that my old CRT projector would be hard-pressed to match.


As far as gamma performance goes, the ML300 comes out of black a little too steeply in each preset image mode and starts to flatline between 60 – 70 IRE. But it doesn’t go into an S-curve response, nor does it clip at the high end. In Movie mode, I measured a 2.24 gamma, while the HDMI input showing video came in at 2.13.

Here's the color temperature track with a 720p HD signal. A little off at the beginning, but very consistent above 30 IRE.

And this RGB histogram shows why the color temperature track is so consistent.


Now for those color gamut plots: You’ll notice right away that the Extended color gamut is ENORMOUS, and big enough to take in all of the digital cinema P3 gamut, sRGB, the original NTSC, and even some laser-powered projector color spaces. Only the green coordinate is out of whack, although the projector’s response is similar to the CIE 1931 observer diagram. For P3, less cyan and more yellow is required.


The Standard gamut is a lot more subdued, and comes very close to the reference BT.709 HDTV color space. There’s just a little too much red and a little too much green, otherwise the colors would be right on the money. But again, it was impossible for me to force the projector into this truncated gamut when watching a Blu-ray movie through the mini HDMI connection – it kept defaulting back to the Extended setting, which made for some very interesting and over-saturated colors.



Here's the flat-out, full-bore Extended color gamut of the ML300, compared to the BT.709 HDTV color space (white outline).

And here is the Standard gamut, again compared to the BT.709 color space. This is looking a lot more reasonable!


LED color appears differently to the eye than dichroic color derived by refracting white light. My test instruments say the two modes are the same, but they still look different to my eyes, just as LCD and DLP color appear differently from CRT color.


Even so, if you can tame the Extended gamut, watching a Blu-ray disc in Standard mode is just as impressive as a standard widescreen business/classroom projector and not all that far behind some of the low-priced home theater projector models with full calibration features. I picked How To Train Your Dragon in 2D as a test disc, along with Planet Earth on Blu-ray for my test videos.


Both had excellent sharpness and detail. They could have been brighter, but I was filling a 92-inch diagonal Da-Lite Affinity screen, which doesn’t exactly make for the brightest images. LEDs cycle as fast as you could want, so there were no motion blur or color wheel artifacts to distract me, even when viewing part of an NCAA basketball tournament game and a prime-time sitcom from NBC.


The ML300 does a passable job of processing 1080i sources to 1080p. It’s much happier with 1080p or 720p content, though. The frequency response is good all the way to 37.5 MHz with 720p multiburst test patterns, and there is some filling with 1080i and 1080p bursts. For computer presentations, try and match the native resolution for optimum sharpness and detail.


Granted, all of these tests are pushing this projector far beyond what it was intended to do, which is to sit on a conference room table and show Powerpoints. But Optoma clearly put some time and effort into the image quality, and you could be quite happy with the ML300 for those “let’s hang a sheet on the wall!” movie nights. God knows it’s easy enough to set up and knock down!




Optoma’s ML300 mobile LED projector is not a toy, nor is it just a garden-variety business projector. There’s a lot more going on here than meets the eye, and you can actually use it for viewing movies as easily as holding court in a small-group presentation.


The IR remote needs to be more responsive and the menu navigation is slow and sometimes confusing. A zoom lens would be nice, but you’ll get used to the 1.5:1 ratio quickly enough. The projector is pretty quiet (36 dB fan noise) and needs a low to mid-range gain screen, say 1.3 to 1.5.


But the ML300’s image quality will surprise you, especially if you remember how crazy the earliest LED projectors looked like a few years ago.


One note: The mini HDMI input connector is a bit unusual and you may not be able to find it easily at your local Radio Shack. I suggest looking on, where I found a pair of ten-foot regular HDMI to mini HDMI cables and two standard/mini HDMI adapters, all for $11.50 and free shipping. Your new point-and-shoot camera probably has mini HDMI connections, too, so these cables are very handy to have.


Optoma ML300 Mobile LED Projector

MSRP: $499.99


Available from:



3178 Laurelview Court

Fremont, CA 94538



Useful Gadgets: Mitsubishi HC7800 3D DLP Home Theater Projector – Pete Putman

Shopped for a home theater projector lately? With all of the attention that new, low-cost LCD and plasma displays are getting, it might be easy to write off the home theater projector market’s future.


Yet, front projection is still the cheapest way to get a big image – for the immediate future, at least. And there are some really good deals out there to be found, particularly in multi-function (2D / 3D) projectors.


Mitsubishi has been turning out some really impressive and affordable home theater projectors for the past six years, starting with the ground-breaking HC5000 and continuing with the high-end 3D HC9000. At last year’s Cedia Expo, the HC7800 made its debut, and I finally got ahold of one to play with. I wasn’t disappointed.


Figure 1. Mitsubishi's HC7800 shares a lot in common with the HC9000 3D projector.




The HC7800 resembles its bigger brother HC9000 in more than one way. The cabinet has that same high-gloss black finish with an aerodynamic appearance, and a silvery-gray trim around the top panel controls, as well as around the front of the lens, which is offset slightly to the left of center.


Directly behind the lens is a pop-up cover that reveals a knob adjustment for vertical lens offset. As it comes from the factory, the lens offset is pretty high, putting the bottom of the image at the optical centerline. The theory behind this decision is that the projector would most likely be ceiling mounted. However, you can dial the image down quite a bit, although you may see some degradation of brightness uniformity at the extremes.


Figure 2. The vertical lens offset knob is hidden behind this door.


Figure 3. Here's the connector line-up for the HC7800.


The standard connector complement includes a single component video input, a 15-pin VGA connector for computers, and a pair of HDMI v1.4a jacks, compatible with frame-packed 3D program formats. Mits has also included an RS-232 port and Ethernet jack for remote control, a pair of 12V triggers for electric screens and anamorphic lens adapters, and a DIN connector that drives the infrared 3D sync emitter.


The supplied remote control should be familiar to Mitsubishi projector users – it’s been standard for several years and provides direct access to inputs, three picture memories, and a bunch of useful tools including color management, frame rate conversion, three iris settings, and the usual brightness / contrast / sharpness / color settings. Brilliant Color mode is also supported.


Figure 4. Same old remote, but some new buttons!




The HC7800 is a single-chip DLP design that uses the latest .65” 1920×1080 DMD imager harnessed to a six-segment color wheel. You may be surprised to see mechanical lens offset married to a single chip DLP light engine, but it has become easier to achieve and essentially de rigueur for home theater projectors – especially when the preferred imaging systems make extensive use of lens shift.


The illumination system revolves around a 240 watt short-arc lamp that can be throttled back to 190 watts in low power mode. In theory, this should provide a pretty bright image – Mitsubishi’s spec for full-throttle operation with no image correction is 1500 lumens – but in practice, you’ll see a much dimmer image after calibration, and may require a gain screen to watch 3D content as a result.


Like other Mits projectors, the HC7800 is equipped with an irising system. It should provide an almost infinite black when activated, but also does some screwy things to gamma performance. My preference is to leave it off and use a low-gain screen to take care of low gray levels. However, that approach doesn’t work so well with 3D content as you will see shortly.




Menu adjustments abound. Mits provides three User presets to store your settings, and you can tweak everything from brightness and contrast to color temperature (six presets plus RGB high and low), gamma (five settings from 2.0 to 2.4 and 3D, plus two user-defined gamma menus), and five picture modes including ISD Day and Night.


The frame rate conversion menu works on multiples of 24 Hz, so when switched off, you are viewing movies at 96 Hz. Want to clean up all the judder and blurred motion while (and I quote) “…retaining the clicking sensation unique to film?” Select True Film mode. There’s also a True Video mode for 30 Hz / 60 Hz content that ups the rate to 120Hz.


Mits has also given you five steps of motion interpolation to minimize 24 Hz blur and make film look more like video. Play with it; you’ll probably find a setting you like. And all of this stuff also works with 3D movies and video, too.


The iris mentioned earlier has four speed settings, plus OFF. That last one is my preference! As I said earlier, variable iris settings can dive deeper into black than James Cameron in the Marianas Trench, but the display gamma is subsequently compromised and inconsistent. Better to use a lower-gain screen and stick with a fixed gamma curve to get the best results.


The HDMI inputs can also be configured for different color modes and black levels settings. In RGB mode, black will be deeper than in video mode, and whatever HDMI output mode your DVD or Blu-ray player is set to should be matched on the HC7800. In theory, the projector should make this adjustment on its own, based on the signal detected from the player. You can also change video setup for every input on the projector, again with black at 0, 3.5, or 7.5 IRE.


The color management tools are intriguing and should only be used with some sort of colorimeter to either read out the x,y coordinates for each color adjustment, or a graphical display of where the red, green, blue, cyan, magenta, and yellow wind up as you change saturation and hue. Don’t try this adjustment unless you can measure the results accurately!


The HC7800 also has a color space adjustment. In Wide mode, the full gamut of the projector is used, regardless of the signal source. In Normal, the color gamut is truncated and closer to that of the Adobe sRGB color space (also closer to ITU REC.709 HDTV). Between this setting and the color management tools, you’ll get well within the ballpark.


Figures 5a-b: The HC7800's 'full' color gamut is so wide...

...that it covers most of the DCI P3 digital cinema color space.


There are so many aspect ratios supported by the HC7800 that I can’t even list them. The owner’s manual shows 38 different possibilities, including anamorphic (two settings), 4:3, 16:9, two zoom modes, and a stretch mode. Leave this control set to Auto and it will generally figure things out on its own! The dual anamorphic modes are used with an accessory lens, with Mode 1 for video playback and mode 2 for sync with computers.


Yep, I almost forgot – this is a 3D projector, too. The HC7800 is compatible with all 3D formats, with frame-packing detected automatically. However, for side-by-side and top + bottom frame-compatible 3D viewing, you’ll have to change the 3D menu setting manually as there is no way for the projector to know what kind of frame it is showing.


The 3D menu lets you reverse the sync on the 3D glasses if the images aren’t rendering correctly. I’ve never had this happen to me, but it’s nice to know you can reverse the problem. There is also a 2D-to-3D processor which results in ‘fake’ 3D imagery by interpolating relative distances of objects in a scene and creating parallax information on the fly. I have never felt any need to watch 2D content in 3D, but I can tell you that the process works – sort of. Stick to native 3D content and you’ll be happier with the results.


The 3D IR emitter is a compact little gadget with a swivel base that you can mount near the projector, or on top of it. The supplied 3D sync cable isn’t very long, and a super-long 3D sync cable like the one supplied with the HC9000 wasn’t included. But this emitter supposedly has a line-of-sight range of about 30 feet.




One thing I like about the Mitsubishi home theater projectors is that they come from the factory requiring little in the way of calibration. The HC7800 was no exception; all I had to do was switch to a deeper gamma setting for Blu-ray discs and fiddle a little bit with RGB contrast and gain.


Brightness after calibration was measured at 388 ANSI lumens in Low lamp mode, jumping to 466 ANSI lumens in High (normal?) lamp mode. That is a lot lower than 1500 lumens, but in general, you’ll see at least a 50% reduction in brightness when calibrating a projector, and maybe more if you use a steep gamma. With the lights off and my Da-Lite Affinity 92” screen, I was quite satisfied with the results.


Brightness uniformity is a challenge for DLP projectors and the HC7800 measured about 80% to the average corner, with the worst corner coming in at around 55%. Color temperature uniformity was within 515 degrees across the screen – not quite as ‘tight’ as I’d like to see, but for a $3,000 projector, better than average.


Contrast numbers were pretty good, but reveal why Mitsubishi wanted to use an irising system. Using a sixteen-square checkerboard, I calculated ANSI (average) contrast at 477:1 and peak (highest/lowest) contrast at 772:1 – nothing to sneeze at! Sequential white/black contrast registered 1048:1, while a 50/50 white/black test pattern yielded a figure of 663:1.

Figure 6a. Here's the gamma curve for 2.4 Cinema mode. Sweet!


Figure 6b. And here's the gamma curve in 3D mode - consistent, but shallow.


The HC7800’s gamma curves are seen in figures 6a and 6b. 6a shows the final gamma for 2D mode with a 2.4 curve selected, while 6b shows the projector after being switched into 3D mode. Many 3D TVs I’ve tested do very strange things to gamma performance when running in 3D mode, and that’s because the brightness and contrast are pumped up to overcome light lost in the glasses.


Fortunately, the HC7800 is a bit more disciplined and doesn’t jump too far off the tracks, resulting in a 1.94 gamma when showing 3D content. That’s not as steep as I’d like, but at least the curve doesn’t clip or flat-top at the high end, and the grayscale ramp out of black looks a lot like the 2D 2.4 gamma when you are wearing active shutter glasses.


After trying to match up the projector’s color gamut to the REC.709 color space, I came up with the plot shown in figure 7. The user controls can get you very close with red and blue, but the green hue adjustment either wasn’t working or doesn’t have enough range – I couldn’t add enough yellow to the mix to line up with the desired 709 locus. But it was close.

Figure 76. I got oh-so-close to matching the REC.709 color space. Oh well, still an improvement...




For my viewing tests, I cued up 2D and 3D versions of How to Train Your Dragon, one of the better 3D movies I’ve seen. And of course, I pulled out my 3D copy of Avatar to see how it showed. For screens, I used the Affinity for both 2D and 3D viewing, and for some extra ‘punch’ set up a Vutec Silver Star 6.0 gain screen to help overcome the losses in the 3D glasses.


As a 2D projector, the HC7800 is a peach. I’m not a big fan of DLP for the home, preferring full-time RGB imaging found in 3LCD and LCoS projectors. But this box performed much better than I expected, and in fact comes close to the performance of the discontinued $12K Samsung SP-A900B in many ways. Its color gamut may not be as accurate, but the HC7800’s color temperature tracking is exceptionally tight and gamma performance is remarkably consistent in any mode.


After spending as much time as I needed on color management and getting the gamma right (between 2.3 – 2.4), I leaned back and enjoyed Dragon in good ol’ flat 2D. I also watched a few CBS and NBC prime time TV shows, caught some NCAA men’s basketball, and also a few cartoons; all the while looking for problems with black levels and color saturation. Didn’t see ‘em!


Viewing 3D required me to put on the ‘newly designed’ Mits eyewear, and wow – were they heavy and uncomfortable! I kinda felt like a Navy Seal on a night ops mission wearing these glasses, which supposedly have faster switching times and reduced crosstalk. But they are big and bulky, and not what I expected after using the latest lightweight 3D specs from Samsung and Panasonic. Even the HC9000 specs aren’t as clunky.


Figure 8. No, they're not night vision goggles. But they feel like it.


Despite their weight and discomfort, the glasses worked very well. Indeed; I saw very little crosstalk as I tilted my head back and forth. But I definitely needed to use the gain screen during the nighttime scenes in Dragon and Avatar – 400 lumens just doesn’t cut it with a low-gain or even zero-gain screen. I could have used 2x or even 3x that level of brightness!


So there’s your puzzler: The HC 7800 is a great all-around projector in 2D mode, but challenged to put enough photons on a low-gain screen in 3D mode after calibration. Aside from using two different screens to watch 3D – or a dual-mode screen, like Stewart now offers – you may want to just crank up the brightness and contrast when watching 3D content and not obsess over the gamma performance, or even the color temperature.




Amazing what $2,999 (or less) buys you these days. I couldn’t help but compare the HC7800’s 2D performance to the Samsung SP-A900B as I was calibrating it…such a deal! Even if you never watch a single minute of 3D content on this projector, you’d be very happy with it matched to a .85 – .9 gain screen. But 3D mode will require some help from the screen, or a lot brighter lamp setting. And I’m sorry, but Mitsubishi has to re-think the glasses – they are just too bulky and uncomfortable for my taste.


Mitsubishi HC7800 3D DLP Home Theater Projector

SRP: $2,999


Available from:


Mitsubishi Electric Visual Solutions America, Inc.

9351 Jeronimo Road

Irvine, California 92618

Phone: (949) 465-6000

Fax:      (949) 465-6013

Useful Gadgets: Channel Master CM-7400 TV

For those readers who are either (a) tired of ever-increasing bills for cable TV, or (b) looking for a different TV experience, I’ve got a product for you: Channel Master TV.


This new product from the folks who were formerly best-known for TV antennas, amplifiers, and related products, is an ATSC receiver with dual DVRs (320 GB total capacity) and tuners, plus built-in WiFi connectivity for Vudu’s streaming HD movie service and Vudu apps. If you live in an area with plots of digital TV stations and are content to give up premium news, sports, and lifestyle channels (replacing some of them with Internet-delivered content), then you should check out this product.



The CM7400 is a stylish, small (10” W x 7” D x 1.75” H) black box with three ‘rubber duck’ WiFi antennas attached to its rear panel. The front panel has a black gloss finish and shows only the power indicator, current time, and indicator LEDs for menu navigation. There’s also a small USB 2.0 port above the clock.


The rear panel is loaded with jacks, including an RF loop-through (two ‘F’ connectors), component and composite analog video outputs, an HDMI output, a Toslink connector for digital audio, a second USB 2.0 port, a 100BaseT Ethernet port, and an eSATA connection, presumably for an external hard drive. Power for the CM-7400 comes from a small wall transformer – there’s no internal supply.

The supplied remote resembles those shipped by TiVo. It provides the usual secondary control of set-top boxes and other connected gadgets in your system, plus volume, channel, mousedisk, and numeric keypad functions.  It’s actually pretty hefty, compared to the box it’s controlling!


To hook up the CM-7400, your best bet is to use the HDMI port, but if you have an older TV, the analog RCA jacks will suffice. Keep in mind you can only get 720p and 1080i resolutions through component jacks – if you want 1080p playback (24-frame or 30-frame), you’ll need to use the HDMI connector. Digital audio is accessible through the Toslink connector, or embedded in the HDMI hook-up.

Does this remote remind of you anything in particular?




The first thing you’ll want to do is configure your channels. Go into the Settings menu and select Channels, and the CM-7400 will prompt you for your location. Scroll to the Local Broadcast option and select it (make sure your TV antenna is connected first!). The box will take a few minutes to scan for all local channels and will also start building program guide information from each station’s PSIP data.


You’ll notice that the box can receive digital cable channels that are not scrambled (conditional access) and if you enter your zip code, will ask you for your cable provider. The problem is; most cable systems are moving to scramble all channels in the future, even over-the-air retransmissions. It appears the FCC will give in on this request (they already have with RCN), so plan on sticking to free over-the-air channels.


The next step is to configure your wireless network. (Or, you can simply plug in a wired Ethernet cable, but wireless gives you more options.) The CM-7400 supports 802.11 b/g/n protocols and will connect quickly to your network – if there is a password, you’ll be prompted to enter it on the remarkably easy-to-read menu GUI, which uses mostly white text on a black background.


Channel Master provides a nice Quick Start Guide to get you through these steps, so you should be up and running pretty quickly. Now, it’s time to watch TV.

Here's the top level menu bar.

And here's the program guide interface.


As I mentioned earlier, the CM-7400 uses each station’s Program and System Information Protocol data to build an electronic program guide. That’s how the DVR knows what programs are coming up in the schedule and when to record them. As you tune through each major and minor channel, you’ll see a program synopsis appear in a black bar at the top of the screen. This bar will list the major and minor channel numbers, the program name, its duration, the rating, and a brief description.


You can also press the GUIDE button and a complete program schedule for all receivable stations will appear, showing 30-minute increments. Scroll to a program listing and press OK, and the scheduler will appear, asking you if you want to (a) record the episode, (b) record the series (repeated scheduled recordings), (c) find other times that the program is scheduled, or (d) manually record the program.


The manual feature is handy if your local station isn’t listing program guide information correctly, or it is simply missing, a problem I had with local station WCAU-10 (NBC) a couple of months ago. Scheduling a manual recording without the correct program guide info is not an easy task, as you have to carefully enter a start and stop time and how often you want to record this time block (One Time Only, etc). For all recordings, you can select the record quality, how long to keep it, and if you want the program to start early or end late in one-minute increments.




The more I used this product, the more similarities I saw to the TiVo interface, which IMHO is the best GUI around for a DVR. About the only things missing from Channel Master TV are “thumbs up and down” controls, an audible “beep” or “boop” each time you execute a keystroke or command, and the program preference and search functions that make TiVo so powerful. Well, you can’t win them all…


As for the Vudu streaming and apps section, you will see a lot of familiar Internet TV services, including Pandora, Facebook, Picasa, Flickr, and some newbies like NBC Nightly News, New York Times, Associated Press, CNN Daily, and quite a few premium channels like Dexter, Californication, Big Love, and TrueBlood. Just select and click away to start watching.

Here's what the Vudu Apps screen looks like.


To test out Vudu, I opened an account and purchased two movies – Bridesmaids (or as I like to call it, The Hangover on Estrogen), and The Help. Yeah, they are both chick flicks, but quite entertaining (in fact, Bridesmaids was flat-out hilariously gross!). Vudu gives you the choice of renting using HDX (1080p/24) quality, HD (720p) quality, and SD (480p) quality. The price difference is small, but you need to check first to see how fast your Internet speeds are.


Channel Master TV will do that for you automatically through the Vudu interface and recommend a quality level. But be warned – Internet speeds vary widely  and typically slow down in the evening during peak viewing hours. My suggestion is to go to the CNET Internet Speed Checker Web site ( and see what your typical download speeds are during the day and at night. You may find that SD mode works most consistently.


My rule of thumb is – up to 2-3 megabits per second (Mb/s) is good for SD video delivery. Figure on 5-6 Mb/s to get 720p HD content reliably, and 8 Mb/s or better for 1080p video. Otherwise, you may find your movie stops abruptly and the Vudu screen will tell you it is “buffering” – something that can take a few minutes if download speeds drop.


Bridesmaids took four tries to start correctly, then played perfectly in HDX resolution until the past 10 minutes when it stopped and started “buffering” again. I dropped down to SD resolution to finish the movie and it didn’t look all that bad on my Panasonic 42-inch 1080p plasma. The Help ran smoothly except for one hiccup near the middle, but this time, I selected SD playback for the entire film. The reason? My average nighttime Internet speeds were dropping into the 2 – 4 Mb/s range.


As for over-the-air channels, the CM-7400 has a very sensitive receiver and evidently uses sophisticated adaptive equalization. What that means in English is reliable reception of weak stations or stations off to the side of the antenna, as well as good reception during periods of signal fading, such as during a thunderstorm. I was able to lock in and watch 38 different minor channels in the Philadelphia market, which is basically a small hotel cable TV system. And they’re all free.


Sports fans should also keep in mind that there is a growing cry to move all cable sports channels to premium tiers as cable bills continue to climb. You won’t need to pay to watch NFL games (available on CBS, NBC, and FOX through 2022), the NCAA men’s basketball tournament, selected major league baseball games and the World Series, SEC and Big Ten football, and the Olympics – not to mention the Masters golf tournament, selected tennis matches, and the Indianapolis 500. All free with an antenna!


I should mention that the test unit seemed to run a bit warm to me, even when it was switched off. One product review on the Channel Mater Web site recommended using a laptop cooler (external heat sink) to help with heat dissipation. Also, Channel Master released an updated version of the OS on January 18, which you should install and upgrade.




Channel Master’s CM-7400 TV DVR is a clever product that nicely combines dual DVRs with Vudu streaming. It has a nicely-designed and executed user interface, sets up quickly, and supports 1080p playback through its HDMI connector. You can also loop your antenna connection through the CM-7400 and continue to watch on your regular TV, giving you the ability to watch three programs at once while recording two of them. Clever, eh?




Channel Master CM-7400 TV DVR

SRP: $400

Available at:

And other online outlets including



  • 480i/480p
  • 720p
  • 1080p/1080i


  • Dolby® Digital and Dolby® Digital Plus


  • Dual ATSC/Clear QAM¹
  • No monthly subscription fee
  • Includes a one year manufacturer’s limited warranty

Recording Capacity

  • 320GB Hard Disk Drive²
  • Up to 35 hours of HD recording³
  • Up to 150 hours of SD recording³


  • Built-in 802.11b/g/n


  • 10(w) x 7(d) x 1.75(h) inches

Rear Panel Features

  • RJ-45 Ethernet
  • USB 2.0
  • HDMI®
  • eSATA
  • Digital Audio (Optical)
  • RF output
  • RF antenna/cable input
  • RCA component and composite video
  • Stereo audio

Front Panel Features

  • Illuminated power standby button
  • Indicators for network status, HD and recording status
  • USB 2.0
  • IR receiver
  • Capacitive touchpad
  • Clock display

Contents Included

  • Channel Master TV Unit
  • User Guide
  • Quick Start Guide
  • IR Universal Remote Control
  • AA Batteries
  • Composite and Stero Audio Cable
  • RF Coaxial Cable
  • HDMI Cable
  • AC Adapter

Useful Gadgets: Super-Flat Indoor TV Antennas – Do They Really Work?

Depending on you believe, Americans are fed up with ever-increasing cable TV bills and are bailing out by the thousands on channel bundles, opting for free, over-the-air HDTV and movies and TV shows streamed over Internet connections.


Or maybe not.


While there’s no question that a cord-cutting movement does exist, it’s hard to tell how big that movement really is. But the allure of dropping $50, $60, $70, or more from your monthly Kabletown bill is strong, and the recent battles between Time Warner and MSG network over rights fees only serve to highlight the inflationary spiral of pay TV services.


If you live in a metropolitan area and have the major networks (CBS, ABC, FOX, and NBC), chances are you already have access to quite a bit of sports programming. Maybe not the 24/7 deluge from ESPN, but you do have NFL games through 2022, selected Major League Baseball games, the NBA Finals, the NCAA Final Four tournament, college football and basketball, and numerous golf and tennis tournaments. (Oh, and let’s not forget next summer’s London Olympics on NBC.)


And if you aren’t into sports, that’s all the more reason to stop paying for programming you don’t watch. There’s still plenty of good prime time programming available for free, not to mention reruns of older cable network shows (Curb Your Enthusiasm was available recently on UHF channel 17 in Philadelphia).


With that in mind, I recently tested a pair of flat TV antennas for indoor reception. The first is the MoHu Leaf antenna ( ,available direct from MoHu for $39.95 plus shipping, and the second is the Walltenna ( , sold by a company known as Urban Freedom LLC for $40 (also at online stores).


Figure 1. The Walltenna is transparent and flexible (and maybe not too attractive).

Figure 2. Mohu's Leaf antenna is also flexible, but opaque and a bit less inconspicious.

Both are marketed to cord-cutters. Both companies cite the trend away from pay TV services “…as more and more viewers look for higher value alternatives” and “…and to get free from recurring monthly cable or satellite bills, high-maintenance rooftop antennas, or bulky tabletop models.”


Do they work? I tested both recently for wall-mount and window DTV reception, alongside two other stalwarts – Kowatec’s UHF panel antenna  (discontinued) and Radio Shack’s model 15-1874 ‘budget’ TV antenna. Let’s see how they stack up.




My house isn’t in the best location for indoor DTV reception. Although it’s less than 25 miles from the Roxborough (Philadelphia) digital TV antenna farm, there is a slight hill and a bunch of tall trees in the way.  Only a couple of UHF stations (17, 26) and one VHF station (6) are strong enough to come through without separate amplification.


The back side of my house looks north towards Allentown, which has DTV stations on channels 9, 39, and 46. And they’re not all that strong, either. In short, I have the perfect location to test these flat antennas – weak signals, but just strong enough to lock up a tuner.


To quantify my tests, I looked at the received waveform for each DTV station on an AVCOM PSA-2500C spectrum analyzer. And I used Hauppauge’s WinTV Aero-M USB stick receiver to verify reception and get some screen grabs of the stations that came in reliably.

Figure 3. (clockwise from upper left) The Walltenna, Leaf, Kowatec, and RS 'budget' antennas in position.



MoHu’s Leaf antenna looks mysterious and ‘stealthy’ with opaque black and white sides, but hold the black side at an angle to a bright light and you’ll see exactly what’s going on under that “luncheonette counter menu” plastic housing: A pair of dipole antennas with X-shaped capacity hats at the ends.


The Walltenna takes that design and makes it larger, except you can see exactly what’s embedded in the plastic – copper foil shaped much the same way as the Leaf antenna. It just doesn’t look as nice on the wall as the Leaf, but then again, some of the best antennas have little eye appeal. (In the eyes of us RF enthusiasts, however, they are things of beauty.)


The significant difference between both antennas – and one which I figured ahead of time would give the Walltenna the edge in receiving more DTV channels – is that the elements on the Walltenna are electrically longer than the Leaf. This means the antenna should be resonant at lower frequencies.


I should point out that neither antenna uses a traditional collinear dipole array, as many rooftop and wall-mount UHF antennas do. With a collinear design, the physical connection ‘crosses over’ from one dipole array to the next, so that each X-shaped dipole array is out of phase with the one behind and/or in front of it, creating a broadband response. In the case of the Leaf and Walltenna, the physical connection to each ‘X’ element remains on the same side of the antenna.


Both antennas are designed to be stuck to a window or fastened to a wall. Mohu doesn’t provide mounting holes, but Walltenna does. On the other hand, Mohu has encased the coaxial cable connection to the antenna in a solid plastic block, while Walltenna simply solders a balun to the copper strips and attaches the balun to the plastic cover with a rivet.


I do not like the latter method at all. First off, inserting a piece of metal between the balun legs at such close range de-tunes the balun lines. Secondly, the balun is stiff enough that it provides too much torque on the base of the antenna when bent – you must be careful not to put too much strain on the connector, and the supplied RG-6 cable jumper is too stiff and heavy for the balun.


Mohu’s antenna comes with a long run of mini 75-ohm coaxial cable. This cable has higher signal losses per foot, but is much lighter and more flexible for indoor installations. Given the rough handling that such antennas are likely to receive, this is a much better approach.




My first test took place in an upstairs bedroom. I removed an oil painting and hung/clipped the antennas to the picture hooks. For comparison, I elevated the Kowatec and Radio Shack antennas and placed them in the same position. This wall position is on the part of my house closest to Roxborough.


After scanning for channels, the Walltenna snagged a few expected stations and a few that were not. Channel 6 (WPVI) runs tons of power to overcome interference from nearby FM stations (Channel 6 is at 85 MHz, and the first strong FM channel in Philly is 88.5). So it wasn’t a surprise to lock up.

Figure 4. (Clockwise from upper left) Spectrum analyzer waveforms of WPVI-6 as received with the Walltenna, Leaf, RS 'budget,' and Kowatec antennas.

Figure 5. (Clockwise from upper left) WBPH-9 and WHYY-12 as received using the Walltenna, Leaf, RS 'budget,' and Kowatec antennas.

Neither was WHYY-12, which also runs beacoup power now that they don’t need to protect channel 12 in Binghamton, NY. WHYY locked up just fine without dropout. WBPH-9 from Allentown was also rock steady.


So were UHF stations WPHL-17 and KYW-26, also a couple of powerhouses. WCAU-34 was mostly reliable with the occasional ‘hit,’ as was WFMZ-46 from Allentown, another strong station. (WBPH-9 and WFMZ-46 antennas were on the wrong side of my house.)

Figure 6. (Clockwise from upper left) KYW-26 as receivedon the Walltenna, Leaf, RS 'budget,' and Kowatec antennas.

Figure 7. (Clockwise from upper left) WFMZ-46 as received on the Walltenna, Leaf, RS 'budget,' and Kowatec antennas.

I could see RF carriers from other stations, but none were strong enough to lock up the Aero-M tuner. Even so, this was impressive performance from a so-called “all band” omnidirectional antenna. What the designer got right was to make the antenna elements longer, which helps with gain at highband VHF frequencies (channels 7-13). But it can also degrade performance in the UHF spectrum – you never get something for nothing.


By using a balanced line connection to the balun, that problem is overcome. At higher frequencies, only the dipole elements are active. At lower frequencies, part of the transmission line becomes part of the antenna. It’s a technique I’ve used for years on ham radio antennas and on my ‘ugly duckling’ UHF antenna prototypes from a decade ago.


So, how’d the Leaf do? Not too bad, but it only pulled in channels 6, 12, 17, 26, and 46 reliably. Channel 9 was nowhere to be seen, while channel 34 suffered from constant breakup. Odd, considering the Leaf is primarily a UHF antenna design and WCAU’s signal on channel 34 is one of the stronger signals around.


The fact that the Leaf pulled in both channels 6 and 12 is a testament to how much power both stations run.  This antenna also uses a balanced line feeder to its coaxial connection, which provides resonance over a wider range of frequencies.


But the ‘X’ elements at the end of the balanced line are only 4.25” long, whereas the Walltenna ‘X’ elements are over 7” long.  So the Walltenna has a decided edge in reception of VHF signals.


How about the two ‘control’ antennas? Kowatec’s panel antenna is usually a strong performer with UHF TV stations, but all it could receive reliably in the test position was WBPH-9, WCAU-34, and WFMZ-69. Radio Shack’s ‘budget’ antenna (UHF loop and rabbit ears) did marginally better, pulling in WPVI-6, WHYY-12, KYW-26, and WFMZ-46.




For the next part of the test, I hung or placed each antenna in a back bedroom window, facing north towards the Allentown and Bethlehem stations. Once again, channel scans were run using the Aero-M and screen grabs were taken of actual DTV waveforms.


I didn’t expect to pull in much from this location, save for WBPH-9 and WFMZ-46. The Walltenna met those expectations and also pulled in KYW-26 as a bonus, off the side of the antenna. The Leaf antenna located the exact same stations with comparable reception results.


The control antennas provided mixed results, but one did marginally better. Kowatec’s panel antenna snagged WPVI-6, WBPH-9, and KYW-26 (no sign of WFMZ-46 and its million-watt ERP signal), while the Radio Shack 15-1874 delivered WPVI-6, WBPH-9, KYW-26, and WFMZ-46.


Obviously all of the antennas could have been placed more carefully for optimum results. But how many readers have access to a signal level meter, or a spectrum analyzer? I’m betting  not many. So my methodology of just picking an arbitrary antenna position yielded a fair set of results.




There’s definitely something to the Walltenna design, but it’s not black magic. Just make the elements bigger and you will approach resonance at lower frequencies. The X-shaped elements on the end act like capacity hats and do the trick! (A full wavelength @ 175 MHz – channel 7 – is 1.7 meters, while a full wavelength @ 665 MHz – channel 46 – is .45 meters.)


The Mohu Leaf is a solid performer on UHF and will pull in the odd VHF station, if it’s strong enough. Both antennas are easily concealed, but take care in what you place them behind or near, as metallic surfaces will detune each antenna and the balanced feed line, degrading performance. (Tip: If a metallic surface is placed ¼ wavelength behind each antenna at the desired frequency, it will become more directional on the opposite side.)


As for the control antennas, they held their own in at least one test, so I can’t say that either flat antenna had a distinct advantage over the Kowatec and Radio Shack entries. Where the flat antennas have the upper hand is in design – they’re easier to hide and to look at . (Although Walltenna should really take a page from Mohu and encase their product in an opaque plastic coating. )

Product Review: A Tale of Two (3D) Televisions

The great 3D TV debates continue as 2011 winds down. “Active 3D is best!” cries one group. “No, passive 3D is better!” replies another. “Don’t jump in yet, wait for autostereo TVs!” warns yet another group.


Here are the facts. At present, there are a handful of manufacturers of active 3D TVs, including market leaders Samsung, Panasonic, and Sony. On the other side of the street, we have passive 3D TVs available from LG, Toshiba, and Vizio.


There are other companies playing in the 3D space to a lesser degree, including Sharp (active 3D) and JVC (passive 3D). And Toshiba is trying to be all things to all people, supporting a few active models and also announcing that they will bring a 55-inch autostereo TV to the Japanese market this fall.


All of this back-and-forth volleying is accomplishing one thing, if nothing else: It’s confusing the heck out of potential buyers. No one wants to sink a few thousand dollars into a 3D TV system and realize belatedly that they picked the wrong horse in the race.


Problem is; no one can say for certain which horse will win that race. Active 3D has its detractors for using expensive, battery-operated glasses that can create eye fatigue in certain individuals from flicker. However, an active 3D TV delivers all 1920×1080 pixels for every video frame in both 2D and 3D mode. And there are no patterned barriers attached to the screen surface to affect 2D viewing.


Passive 3D has simplicity and lower cost going for it – you can use the same circularly-polarized glasses you brought home from the local Cineplex – but presents a visible artifact in the form of horizontal patterned film retarder lines when watching 3D content and sitting closer than 2x the screen diagonal. And passive 3D TVs have very narrow ‘usable’ viewing angles, compared to active 3D TVs.


As for autostereo, let’s just say right now that it’s not really ready for prime time yet, based on what I saw at CES 2011 in the Toshiba booth. The appeal of glassless 3D is easy to understand, but it makes the design of the TV much more complex. Plus, there’s a tradeoff: The more ‘views’ you have on an autostereo TV, the lower the overall resolution of each view.




In my tests of 3D TVs, both active and passive, I look very carefully for evidence of ghosting, or double images. Ghosting is caused by insufficient suppression of opposite-eye images, and results in double vision (and often, headaches).


The ability of a 3D TV design and its associated eyewear to suppress ghosting is called its extinction ratio.  The laws of physics say that active LCD TVs will have a harder time suppressing ghosts than plasma TVs, and that’s because of all the polarizers used in a typical LCD TV: They interact with the polarizers used in 3D eyewear and can cancel each other out.


There is even an inconsistency among active 3D TVs. Samsung and Panasonic use dual polarizers in their active eyewear. Sony, however, opted to go with a single polarizer for two reasons. First, the resulting images are brighter. And second, it helps to minimize flicker and eyestrain. But there’s a trade-off, and that is a lower extinction ratio and lots of ghost images with small head tilt.


Passive 3D TVs don’t get a free pass here. One set of polarizers is mounted on the TV screen surface (those afore-mentioned film patterned retarders) to work with the other set in the ‘el cheapo’ passive glasses. At certain narrow viewing angles, their extinction ratio is quite high. But at comparatively small offset viewing angles, the double images are apparent, as I’ll demonstrate shortly.




I decided to see what the fuss was all about with passive 3D TVs and lined up a pair of 47-inch models to see what they could do. LG’s 47LW6500 ($1,399) is at the top of their 3D TV line and comes with four pairs of passive glasses. It’s a 240 Hz LED-backlit LCD TV with four HDMI inputs (1.4a compatible, of course), plus a host of network functions (Smart TV) and other bells and whistles.

Figure 1. LG's 47LW6500 3D LCD TV

Figure 2. Toshiba's 47TL515U 3D LCD TV

Toshiba’s 47TL515U ($1,299 SRP) just came to market and offers much the same goodies as the LG Set. (I’ve been told it even uses LG Display panels.) This is also a 240 Hz LED-backlit LCD TV with 4 HDMI inputs, Net TV, and one leg up on the LG set: It’s equipped with the new InstaPort HDMI connector. That means fast switching between HDMI sources.


To be honest, there’s not a whole lot of difference between the two TVs. The LG scans TV channels faster; the Toshiba changes inputs faster. Both TVs have multifunction remotes, but the Toshiba remote is far more complicated and difficult to use. There are just too many small buttons, and the navigation mousedisk is mounted coaxially inside a second navigation ring, which also has four pushbuttons on it. You can’t use this remote easily even with the lights on.


The LG remote is FAR more user-friendly, with big, white buttons, large blue volume and channel controls, and a simpler mousedisk for navigating through menus. In addition, the LG’s 3D on/off button is nestled between the volume and channel rocker switches and clearly marker “3D” in bright red. In contrast, it took me a while to find the 3D mode button on the Toshiba – it’s part of a row of four tiny black buttons near the bottom of the remote.

Figure 3. Which remote would you rather use? And can you find the 3D buttons?

Figure 4. Here they are!



The menus on both TVs leave a bit to be desired. Toshiba’s menus appear as rotary icons near the bottom of the screen. You scroll (spin, rotate) left or right to bring up the desired menu, then hit select and start making your choices or adjustments. It’s a bit different than the usual horizontal bar menus, but you’ll get used to it quickly enough.


On the LG set, pressing the Home button brings up a master screen that shows Smart TV icons, a settings icon, and an input icon. Whatever you’re watching on screen is reduced to a small window. You then have to navigate to the ‘Settings’ button and select it to get into any menus. It’s slightly annoying, but you shouldn’t have to adjust it very much.


I usually go into more detail about menu settings here. Suffice it to say that both TVs give you a full range of adjustments over images, with the exception of 3D. The 47LW6500 has two ISF Expert modes in addition to Intelligent (ambient light sensing), Vivid, Standard and Cinema presets, and you can get the TV’s white balance very close to the BT.709 target of 6500 degrees pretty easily. Ditto the 47TL515U, which also has an ‘expert’ mode for calibration, and offers two Movie modes, Sports, and Autoview (ambient light sensing) presets.


As mentioned earlier, both TVs offer 240 Hz scanning and de-judder circuits that can convert a film look to live video, along with automatic contrast, adjustable gamma, and black level settings. All routine stuff and all things you should shut off if you want to calibrate either TV to work at its best. The digital noise reduction circuits are handy if you are viewing video content that has been over-compressed. That shouldn’t be much of a problem with HDTV programs, but is quite common with standard-definition programming.




What I was interested in seeing was how well each TV worked in 2D mode after calibration, and what happened to image quality when 3D mode was selected. Here’s where the biggest difference was found between the two TVs – the 47LW6500 will not let you make ANY adjustments or access any menus in 3D mode, while the 47TL515U will. And if you think that’s not such a big deal, have I got some histograms for you…

Figure 5a. Here's the gamma curve for the 47LW6500 after calibration - a beautiful 2.31 arc.

Figure 5b. And here's the corresponding after-calibration 2.44 curve on the 47TL515U.

Figure 5a shows the final gamma curve for the Toshiba, while 5b shows the LG gamma after calibration. Both curves are consistent coming out of black and mimic the performance of a CRT. Where things get dicey is when 3D mode is switched on. The LG TV switches to a much brighter image with higher black levels and an S-curve gamma, which measures approximately 1.5 – and there not a thing you can do to fix it.


On the other hand, the Toshiba set exhibited a remarkably consistent gamma after its 3D mode was turned on, with a curve similar to 2D mode that measured 2.36. AND you can go back into the menu and tweak it if you want to.

Figure 6a. Yikes! What happened to the LG's gamma performance?

Figure 6b. Toshiba maintains its gamma settings even in 3D mode.

How about color temperature? Figures 7a and b show grayscale tracks for both sets in 2D mode, and they’re looking pretty good, eh? But switch to 3D mode, and as you can see in figures 8a and b, the 47LW6500 jumps way above 9300 degrees, while the 47LT515U doesn’t move nearly that high (about 6800 degrees) – and again, you can fix it.


This is what you don’t hear about 3D TVs: Their 2D calibrations usually go out the window when 3D mode is selected, and most of the time, you can’t do a darn thing about it. Fortunately, Toshiba does preserve your ability to compensate for any shifts caused in 3D mode.


Let’s talk about color accuracy. HDTV content for television and released on Blu-ray disc is supposed to conform to the ITU BT.709 color space, which produces colors that are somewhat less saturated than the full color gamut of LCD and plasma TVs. So to be ‘precise,’ any TV ought to match that color encoding as closely as possible.


Guess what? Both TVs do just that, as seen in figures 9a and 9b. LG gets the blue ribbon for coming closest to the desired RGB and CMY coordinates and both sets provide color management software (CMS) to fine-tune the x,y locus of each coordinate. Note that the coordinates shift on both TVs when in 3D mode (why is that???) and the shift is more noticeable on the LG TV, as evidenced by the green, cyan, magenta, and yellow targets.

Figure 7a. The 47LW6500 tracks a stable grayscale in 2D mode...

Figure 7b. And so does the 47TL515U.


Figure 8a. Switch to 3D mode on the LG, and all bets are off with respect to color temperature.

Figure 8b. Meanwhile, everything is rock-steady in 3D on the Toshiba.

Figure 9a. Here's the 47LW6500's color gamut. The dark outline is the BT.709 color space.

Figure 9b. And here's the 47TL515U's color gamut, mapped against the BT.709 color space.



For my viewing tests, I used a Blu-ray copy of Avatar, played out from a Samsung C6900 3D BD player. Since both TVs use circular polarization in their eyewear, I was able to watch with many different pairs of glasses and saw no difference in the results.


First off, 3D images seemed to have more depth on the Toshiba. Can’t tell you why that was, but I definitely noticed it. Not to say that the LG set didn’t do a good job  – it did, but the Toshiba 3D images seemed to be more realistic, especially in the scenes with people gathered around the sacred trees, campfires, in the lab, and in the war room.


Color quality was better on the Toshiba for the reasons enumerated in the previous section. It doesn’t jump that far out of calibration in 3D mode. The LG TV does get considerably brighter and colder in color temperature, and the overall picture quality isn’t as pleasing to the eye.


Both TVs seem to switch on their motion de-juddering circuits in 3D mode, so you need to make sure that function is disabled completely if you want a true ‘film’ look when watching 3D Blu-ray discs. Look for a menu function that shuts down 240 Hz mode. (And make sure you’ve shut off ALL other picture enhancements like dynamic contrast, auto black levels, etc.)


Now for my viewing distance suggestions. I generally counsel people to shoot for a seating distance equal to 1.3 – 1.5x of the screen diagonal, in order to get a more immersive 3D effect. That rule of thumb works great with active shutter TVs, and also holds true for 3D front projectors, but it doesn‘t hold up with passive 3D TVs.


The reason? You’ll see the FPR lines, which appear as thin, horizontal black bands. Close one eye or the other, and there they are! In fact, you’ll see them with both eyes open, and it’s like the old ‘screen door’ effect with low-resolution LCD projectors from the mid-1990s. Kinda distracting, in my opinion.


So it forces you to sit farther away from the 3D TV, which is exactly the opposite of what you want to do! The best 3D experiences come when the screen fills 50% or more of your field of view, and you’ve removed as many distracting 3D artifacts from outside that field. That’s one reason why 3D works so much better in movie theaters than at home – there is practically zero ambient light and the screens are big, so your brain locks onto the 3D illusion much more quickly.


Practically speaking, you need to sit about 2x the screen diagonal (94”, or about eight feet) to minimize the FPR lines. I’ve tested this viewing distance with a variety of viewers, young and old, and it holds up. And that, in my mind, is the big strike against passive 3D: You want to sit closer, but you can’t because of this picture artifact.


The other artifact you’ll notice from time to time is crosstalk. It depends on your viewing angle and the type of content, but it is most often seen with titles, high contrast fine detail, and angular objects on light backgrounds. I created a few test patterns to check for crosstalk and you can see the actual results in figure 10a. Both TVs suffer from this problem – it’s a direct consequence of using FPRs.

Figure 10a. Here's what crosstalk looks like on a passive 3D set.

Figure 10b. Here's the view through one eye of a passive 3D image. You can see the FPR lines running horizontally along the walkway in the foreground and across the railroad tracks.

Figure 10c. Here's a close-up view of the FPR artifact.



Did I mention that both TVs make some beautiful pictures in 2D mode? No FPR artifacts are seen here; just full-resolution 1080p images with good contrast and color saturation. In fact, the 47LW6500 is one of the better 2D LCD TVs I’ve tested recently, and the 47TL515U is right up there with it.


The devil is in the details, and in 3D mode, the 47TL515U is clearly the better performer. Just the fact that it lets you fine-tune image settings while in 3D mode is a BIG plus in my book. It is nice to know that all of your hard work in 2D mode won’t be lost, and you’ll see some really good-looking 3D as a result.


With the 47LW6500, you are out of luck. 3D pictures will be a lot brighter, black levels will elevate, and white crush will be present… and you’ll just have to live with whatever the TV shows you. If there’s any consolation, you’ll get into 3D mode a lot faster with the LG TV ( that big fat 3D button is a great idea) and the Toshiba isn’t as user-friendly when it comes to the remote control.


By the way, both sets support all standard 3D formats, including side-by-side and top + bottom frame compatible, and the frame-sequential Blu-ray format is recognized automatically by both TVs. (You can also horse around with converting 2D to 3D, if you have nothing better to do…)