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Product Review
 

Sanyo PLV-Z2 Three-Panel 16:9 LCD Digital Projector

Part II

May, 2004

John E. Johnson, Jr. and Steve Smallcombe

 

Measurements and Viewing

First, let me say that the Sanyo Z2's picture is twice as nice as my much more expensive Sony 10HT. And, it has that lens shift that I like so much.

The picture is bright and contrasty, areas in which my 10HT didn't do so well. Colors are vivid.  However, the Z2 (like all projectors) does have its problems.

The rated contrast is 1300:1. Our tests, using full on, full off (the entire screen was either all white or all black), yielded a contrast ratio of 278:1 with the ColorFacts system and 600:1 with the SMART III system . However, this is still OK, and was a whole lot better than my 10HT. Nevertheless, the dark areas of scenes were just a tad muddy, compared to some of the DLP projectors that we have tested. However, those shadows looked blueish rather than reddish or brownish, and this is easier to deal with, at least for my eyes.

The Screen Door Effect (SDE) was moderate. I could see it from a few feet away, but not at normal seating distances. The good news is that this also indicates a nice sharp lens. I was afraid that, at $2,000, Sanyo might have cut corners on the lens quality, but it seems to be a good one.

Both brightness settings yielded satisfactory images. However, I preferred the brighter setting for most movie watching. Measured light output, untweaked, was 776 ANSI lumens. This is represented by 26.1 ftL (foot-Lamberts) in the bright setting, and 13.6 ftL in the lower brightness setting. After Steve added a CC 40 red filter (see graphs below), the light output was reduced to 8.6 ftL in the brightest setting. The blacks were greatly improved, but you would need a screen with some gain (say, 1.2) for optimal viewing.

The fan noise is almost imperceptible. Nice to see that manufacturers are building such quiet projectors these days.

Color Decoder

Using a component progressive input and the appropriate test images on Avia, I (Steve Smallcombe) found the proper Color and Tint settings were the default values of 0 and 0, and the Avia Color Decoder test revealed no significant “push” of any color – in other words, excellent performance.

Scaler and Deinterlacer – the Video Essentials Montage

Although I now have the newer Digital Video Essentials, I still find the now familiar Montage on the original Video Essentials disc essential for checking out new projectors – especially with respect to the performance of the deinterlacer. For the Z2, I needed to compare three modes: interlaced and progressive from a Denon 1600, and DVI from the Bravo D1 at 720p resolution.

All modes tested well with interlaced signals looked essentially the same as progressive signals from the Denon 1600, indicating that the the Z2 was doing a very good job of deinterlacing NTSC signals.

In fact, there were more obvious jaggies on the waving American Flag, using the DVI input, compared to the other two modes. In general, the DVI image looked very good, and bleachers, bridges, buildings, and leaves were well handled by all modes of operation. Since I saw this same issue with the much more expensive Sharp 12000, it may well indicate that the deinterlacing errors with DVI are in the DVD player, not the projector. When the projector is receiving 720p, that since the signal is both progressive and at the native resolution of the projector, any apparent scaling or deinterlacing artifacts must come from the source.

Lamp and Iris Modes

The Sanyo Z2 has three lamp modes and an adjustable iris that allow considerable control over the total light output of the projector. The iris is a mechanical device in the lens, and by closing the iris, you can reduce the light output of the projector to about 60% of the open iris light levels. By measurement (SMART III) the iris control has no effect on contrast ratio, as would be expected for an LCD projector, despite the fact that the Z2 manual suggests the user adjust the iris setting to control the “contrast” of the image.

Having a high and low lamp modes is pretty typical with projectors aimed at the HT market – the high mode gives the maximum light output, and also the maximum fan noise. Many therefore prefer the lower lamp mode to extend bulb life, reduce fan noise, and increase black levels, although at the expense of overall light output.

The Z2 has a third mode of operation, the A or Automatic mode where the lamp brightness is modulated to give more light in bright scenes and less light in dark scenes. If done correctly, lamp or other forms of overall light output modulation, have the potential to considerably extend the effective dynamic range of contrast ratio of a video projector. If done poorly, changes in the light level would be obvious, and look artificial.

The A lamp mode on the Z2 seems to work very well, giving almost the full light output with an IRE 100 window, the improved black level of the low lamp mode, and by measurement, adds at least a hundred points to the contrast ratio. Yet the effect is subtle and never obvious during operation. I found the fan noise in the low mode, the best (lowest) I had ever heard, and in the A mode, very acceptable as well. As with many things, the perfection of the art is in its deception, and Sanyo has done this very well. I would certainly recommend the A mode for normal operation.

As much as the bench tests show the problems, we still enjoyed the heck out of this projector. The dips and bumps on the curves make it seem much worse than it is. The eyes adapt very well to these problems, and the movies looked great. It is ironic that the Sanyo deep shadows have a blue cast, as that is what some color films do as well. This is probably one reason why Film Noire movies of the 1940s were shot in black and white. They could not get good shadows with color film, and Film Noire had plenty of darkness.

On the Bench

A color temperature histogram is shown below. This was measured using factory default settings (no color boost, mid level tint, etc.) as shown in the menu screen shots in Part I of this review. (Bench test measurements were performed using the Milori ColorFacts analysis system which generated the signals, and the computer's video card S-Video output. The Smart III Video Calibration System was also used, with a DVD player supplying the video signals through DVI and component outputs.)

The color temperature at low IRE was very blue, and I could see this on the screen (very dark gray looked blueish). At the rest of the IRE levels, the color temperature was still hot, but quite watchable. Of course, you can adjust the color temperature by changing the blue settings or the tint. However, this did not flatten the curve. The dotted line on the histogram is 6500 degrees Kelvin. This is the desired color temperature. Above that temperature, the color becomes more blue. Below it, the color becomes more yellow.

The RGB levels show the rise in blue and drop in red at low IRE. This is why the dark shadows look blueish.

Gray level tracking is shown below, using a gamma of 2.2 as reference. You can see that it tracks fine at low IRE, but strays from the 2.2 standard at higher IRE levels. What this means is that, with low IRE input signals (shadow areas in movies), the Sanyo puts out the correct brightness, but with mid-high IRE signals, the Sanyo's projected image is somewhat brighter than it should be. The projector is getting too bright, too fast at the higher IRE levels, and this "crushes" the dynamic range. Turning down the contrast can help alleviate this, and many manufacturers boost the contrast for the "factory settings" as this gives the image some zip in a demonstration.

The CIE 1931 color space for the Z2 is shown below.

The shark fin-shaped colored diagram shows the range of colors that the human eye can see. The dark triangle indicates the color space, or gamut, that is standardized for HDTV. The white triangle is the gamut of color that the Sanyo showed in our tests. The curved line is called the Black Body Curve, and shows the colors that black bodies (in a lab, this is a 1 cm cube of platinum) emit when they are heated to different temperatures. The indicated temperatures are in degrees Kelvin (K). Point C is for the NTSC reference between 1953 and a few decades later, when it was replaced by the D65 point. The point labeled D65 is the ideal point for HDTV, which is the white reference (no red, green, or blue tinge to the light), and has a color temperature of 6,500 K (the convention is not to use the degrees symbol). The cluster of white circles to the left of the D65 point is where the Z2 tested, which means that it tended to have a blue cast to the image at all IRE levels.

Tweaking the Z2

Using the SMART III system, here are the color balance graphs: The first one shows the R,G,B levels with the color temperature on the Z2 set to "Mid", just as was done with the ColorFacts system. The trend in the three color lines is the same as shown with the ColorFacts system. Like many LCD projectors, the Sanyo Z2 uses a bulb that is weak in red. With the "Mid" color temperature setting, one can see that red is deficient at most IRE levels, and especially at the at the lowest levels.

Normally, this problem can be fixed by adjusting the various gains, or drive levels for the various colors, to achieve proper color balance at the high IRE levels, and use bias or offset controls to tweak the low IRE levels. With the Z2, attempts to correct the color balance at IRE 70, e.g., by either adjusting individual R, G, and B controls, or by selecting a “Low” color temperature give an excess of red at the mid IRE levels without correcting the higher IRE levels. Many that have tried to tweak the Z2 using service and user menu controls, have found that if pushed at all, the gamma tracking for red is very different than for green and blue, giving the problematic grayscale tracking shown above. Red just seems to want to roll off at the high IRE levels, and the tweaks that work with the Z1, simply don’t work with the Z2. With the Color Temperature of the Z2 set to "-2", notice how the lines shift in the graph shown below.

One solution to this problem is via the use of CC filters, or a red filter in this case. Using a combination of a CC 40 red filter and the service mode, I got much improved grayscale tracking, shown below. However, the use of the CC 40R filter, combined with lowering several of the gain settings, reduced the overall light output of the Z2 to 8.6 ftL with my unity gain 102 inch diagonal Da-Matte screen. With a smaller screen, or a screen with some gain, this total light output might be fine, but for me, it was a bit dim.

My next attempt at tweaking the Z2 therefore used a CC 20R filter. Although the grayscale tracking is not quite as good as with the CC 40R (graph shown below), after a final tweak of the contrast, I had 14.5 ftL, in the High bulb mode, and 13.2 ftL in the A lamp mode – an image right in the middle of the ideal range. The contrast ratio with the CC20R filter and as tweaked, was 713:1, considerably better than my Reference, CC filter tweaked, Sony 11HT.

If you would like to see what the data are for my Sony 10HT (tweaked by Steve Smallcombe), click on the thumbnail photos below. The temperature histogram is closer to the 6500 K point. The RGB histogram has the three primaries nearly lined up together. The CIE shows that the Sony 10HT has a gamut very near the HDTV ideal. However, even tweaked, the Sony has a contrast ratio of less than 200. That is lousy by today's standards.

Sony 10HT Temperature Histogram

Sony 10HT RGB Histogram

Sony 10HT CIE

The Z2 gamut indicates it is rich in green and red, but deficient in blue, compared to the HDTV gamut, so this means that it is possible to tweak the projector's settings to make it more in conformance with the HDTV standard, since the green and red gamut lay outside the HDTV gamut, rather than laying inside.

Keep in mind that these test data are for the default settings in the Z2 menu. The data change dramatically when the gamma is altered, or when the tint or individual primaries (red, green, or blue) are changed. So, essentially, these are data for the projector "Out of the Box", or "OTB", and with no parameter turned up or down.

Conclusions

For $2,000 (street price), the Sanyo Z2 is a good projector. Sure, you can get better contrast with some of the DLP units out there, but in that same price range, they don't have the resolution.

The Z2 is very affordable, is easy to set up, and is watchable out of the box even without any tweaking. However, it can be tweaked such that the picture is quite excellent.
 

 - John E. Johnson, Jr. and Steve Smallcombe -

 

© Copyright 2004 Secrets of Home Theater & High Fidelity

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