Samsung HLxxA750 LED DLP Rear Projector

DLP rear projection is an endangered species. Most critical viewers (myself included) believe that flat panels offer significant advantages—both practical and performance-based—over rear projection. Flat panels are thinner, often lighter, and offer a sharper, more 3-D image. However, until recently flat panels, as attractive as they are, were beyond the budget of most consumers. In the last couple of years that has changed. The prices of flat panels—both plasma and LCD—have now come down dramatically in the 58" and below sizes.

There really only remains one reason to purchase a rear projection display: You can get a very large screen for a quite affordable price. For example, the MSRP of Samsung's 67" inch LED DLP rear projector is only $2,400. Samsung's own 63" plasma is $3,500. Panasonic's 65" plasma will set you back a cool $6,000. Thus, if you want a really big screen, and you don't want front projection, and you also don't want to break the bank, rear projection is still a viable choice.

Nonetheless, the writing is on the wall. Only two manufacturer's continue to sell rear projection units: Samsung and Mitsubishi. Furthermore, Samsung's effort is half-hearted. They have reportedly ceased all further development in the technology, but Samsung will still sell you one if you are in the market.

The rear projection market used to offer a wide range of display technologies, including CRT, LCD, LCoS, and DLP. CRTs became obsolete a few years ago. Both JVC and Sony have now exited the LCoS rear projection market, though they continue to market successful LCoS front projectors. LCD is limited to flat panels and front projection. That leaves DLP as the lone display technology for the rear projection segment.

Samsung's DLP rear projectors share certain corporate similarities with their flat panel cousins. In particular, all use a Movie preset that is reasonably accurate. So if you don't want to have your set professionally calibrated, Samsung is a good choice because their user menu presets will get you 80% of the way there.

What's interesting about Samsung's approach is that not only do they provide reasonably accurate presets, they also offer among the widest range of calibration controls in the business. For this reason, Samsungs are a favorite among calibrators because we have been given an amazing amount of control over the image quality. Needless to say, I like calibrating Samsungs.

This is also true of their DLP displays with a couple of differences. First, unlike many of Samsung's plasma and LCD flat panels, the DLPs sets do not offer a full range of calibration controls in the user menu. You must use the service menu to get the best out of the them. Second, and much more importantly, the procedure for calibrating Samsung DLPs is infinitely more complex. On a Samsung plasma or LCD flat panel, calibration consists simply of adjusting slider bars up or down to obtain the desired performance characteristic which can be measured in real time as the adjustments are made. The DLPs are, in contrast, much less straightforward. You can't make adjustments and measure the results in real time, because the adjustments must be made in the service menu and what you measure there does not apply to the user menu. Thus, calibrations require going in and out of service menu many times to get it right. Also, being a service menu, the options are labeled in often obscure and sometimes redundant ways, so it is not always clear what to adjust and in what order.

I learned this the hard way when I attempted to calibrate one of these without the benefit of step-by-step procedures provided by Samsung to ISF calibrators. Having worked on over a hundred displays I thought that I could figure it out on my own. I couldn't. However, with the aid of the aforementioned instructions, I was able to finish the calibration fairly straightforwardly. Here are the results.

White Balance

First, the post-calibration white balance (or grayscale) is among the best I have ever encountered.

Color Performance

Second, the service-level CMS allowed me to obtain very good hue and saturation figures and relatively low dEs for the primary and secondary colors. The CMS, which is actually a Texas Instruments utility available to all DLP manufacturers called CCA, is a system whereby you measure the xy coordinates of the color points and then you calculate an offset required to bring them into spec. Then using the CCA, you input those numeric values and the system recalculates the desired chromaticities. It is a tedious and clugey process, but it works. Unfortunately, the system is 2-D only so you can adjust the hue and saturation of colors, but not their brightness. You can use the main Color control to adjust brightness somewhat, but it is a blunt instrument with undesirable side-effects that only helps a small amount. As it happens, the brightness values of the primary and secondary colors are all reasonably accurate, except red, which is considerably exaggerated. This what we used to call "red push." The inability to bring red brightness into spec without substantially undermining the color performance elsewhere is the CCA system's main weakness. This is actually Samsung's fault. TI offers a 3-D CCA, which I have used on other displays, but Samsung simply doesn't implement it.

A detailed analysis of the color performance is shown below.

Contrast and Gamma

So the white balance and the color are both quite good on this set post-calibration. The gamma is quite good as well. It averaged a near ideal 2.2 with values slightly higher at the top end and slightly lower at the bottom end, as shown below.

If this display has one achilles heal, it is the black level. Post-calibration is measured 0.025 fL. With peak white at 33.3 fL this provides an on/off contrast value of 1326:1. This is slightly lower contrast than Samsung's own plasmas and considerably lower than their most recent LCDs. This is also considerably lower than the conventionally illuminated A650 series. The A750 models use a LED lighting engine. This has some real benefits. It runs cooler, turns on faster, lasts much longer, and, most importantly, eliminates the need for a color wheel. Instead of a color wheel, the LED simply blinks off and on to provide the sequential color of single-chip DLP. However, it is able to turn off and on much faster than a color wheel can turn. For this reason, the LED lighting engine results in a dramatic decrease in color separation artifacts, for those who are sensitive to this (most people are not, including me). The downside of the LED engine, at least this implementation of it, is a higher black level.

For this reason, if you are not sensitive to DLP rainbows, I would recommend the less expensive A650 unit.