Sony G90 - Manual (Page 78)

horizontal and vertical scan frequencies and other source
information can be displayed at any time. A phosphor saver
function is provided to periodically shift the horizontal and
vertical image position on screen to avoid a CRT burn. This
function can be turned off if desired, although I believe it is a
worthwhile function to use. If a very slight overscan is added
to the picture the effect of this screen saver function will not
be noticed.
Performance
I used a Runco IDP-980 Ultra for this evaluation. Its video per-
formance is identical to the DTV-930 with the point conver-
gence option, for everything discussed in this review.
Color accuracy is primarily dependent on two factors,
grayscale accuracy and how well the red, green, and blue pri-
mary colors match the SMPTE standard. The latter is fixed for
each model of projector based on its CRT phosphors and any
additional filtering in the lens-CRT assemblies. The grayscale
accuracy must be calibrated and will degrade if the projector
is asked to supply too much light because the blue CRT phos-
phors will begin to saturate at high output levels. To achieve
the best grayscale accuracy, and therefore good color accura-
cy, the screen size and image brightness must be appropriate
for the projector. Generally, the larger the CRTs the more light
output they can provide while operating in a linear grayscale
range.
For this projector I used an 89” wide screen and set the
contrast for 7.75 ft-L measured at the screen plane, which
equates to about 10 ft-L on axis for the 1.3 gain screen. This
combination is about the reasonable limit to achieve an
acceptable grayscale and good color accuracy. If you want a
larger display you can select a higher gain screen, but you will
probably find hot-spotting and color variations across the
screen unacceptable if you have a critical eye. The projector
is also capable of much higher light output levels but the color
accuracy will suffer as a result.
Using this set-up I adjusted the grayscale for the SMPTE
standard color temperature of 6500K, +/- 400K over the range
of 20 IRE to 100 IRE. These adjustments were made while
using a Faroudja VP250 line doubler. Since the scan lines
don’t overlap with a doubler, a tripler would provide even flat-
ter grayscale results since the blue CRT will provide more out-
put before the onset of phosphor saturation. The colorimetry
of the green and blue phosphors is quite close to the SMPTE
standard and the red phosphor is a slightly deeper red. The
result is near perfect color-bar patterns and excellent color
accuracy on movies. Skin tones look exceptionally accurate
while full color-saturation is maintained elsewhere in the pic-
ture. With good DVD transfers there is no need to reduce the
line doubler’s color control to prevent overly red faces that
would desaturate (washout) other portions of the picture.
(See measurements.)
Other key performance characteristics of any video dis-
play are its ability to provide a geometrically stable picture
and constant black levels as picture luminance levels change.
The latter can render black-levels gray and dynamically
reduce the contrast ratio of the picture. These attributes are a
function of good high-voltage power supplies for the CRTs.
Some products, particularly RPTVs and direct-view monitors,
suffer size or geometry changes as the average picture level
(APL) varies. Examples include static changes when a bright
object enters a dark scene, or momentary effects during
bright flashes. On this projector the high volt-
age system holds picture size and geometry
rock solid regardless of steady state or tran-
sient changes in APL. The new Alien DVD is
an excellent test of these capabilities with its
dimly lit interiors that are punctuated by
bright flashing strobe lights in one scene. Black level is also
well maintained with APL changes.
Spot size and focus uniformity across screen is excep-
tional for CRTs of this size. I compared resolution and picture
definition on some of the best DVDs to the performance of the
Sony G90’s 9-inch CRTs. Alien and The Fifth Element are two
movies that have some of the best detail. The G90 provides a
modest increase in the sharpness of fine details in direct A/B
comparisons. Both projectors are capable of performance
beyond the resolution limits of the DVD format.
A line doubler will work well with this projector when
viewing 16.9 enhanced and 4:3 DVDs on a widescreen from
about 4 PH (picture heights), but scan-line structure will be
visible on 4:3 letterboxed DVDs. If you are sensitive to scan-
line visibility, then a line tripler would be better for non-16.9
enhanced letterboxed sources and it will allow you to move
up to the “ideal” 3.3 PH if you desire a wider field-of-view.
It’s well established that 9” CRT projectors are required to
reproduce the full resolution of 1080i HDTV. But does that
mean HDTV looks blurry or unimpressive on this projector?
Definitely not! HDTV broadcasts look breathtaking and clear-
ly distance themselves from the best DVDs. I used PBS broad-
casts as my HDTV source. It was no contest with any of the
rear projection HDTVs on which I’ve viewed the same mater-
ial. Picture clarity and definition on the Runco is far superior.
The gap between the Runco and the Sony G90 is not as wide,
but the G90 really does capture that sense of looking through
an open window. Perhaps the Runco is more like looking
through a double-pane window. The G90’s detail and sense of
depth is significantly better in direct comparisons, but unless
you’ve already acquired a trained eye for HDTV on a 9” CRT
projector you’d better sit down, because the Runco DTV-930
will knock you off your feet.
Summary
If there is anything in home theater priced a few DVDs over
$16,000 that can be considered a bargain, it is the Runco
D T V-930 with Ultra option. If you are in the market for any-
thing less than a 9” CRT projector, you owe it to yourself to
see this projector optimally set-up and calibrated. But you’d
better hurry. The chassis used for the DTV-930 was a last
time buy for Runco, and when they are gone, they are gone
for good.
RUNCO INTERNATIONAL
2463 Tripaldi Way
Hayward, California 94545
Phone: (510) 293-9154
www.runco.com
Source: Reviewer purchase
Price: DTV-930 $14,995;
DTV-930 w/point convergence $16,195
M a n u f a c t u r e r I n f o r m a t i o n