I just typed up a review of my observations of Cliff's G 90 double-stack. I know he's been wanting to see what I was gonna say -
Here it is -
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I was finally able to settle back here today and write a spell, having gotten home yesterday late from Midway airport, and have been chomping at the bit to report on Cliff's G90 stack, in more detail.
This system really has to be experienced to be believed. Gotta say, the screenshots Cliff has been putting up here in this section are amazing, but nothing can prepare you for the ultimate event of being immersed in it, in action.
He uses a 1 gain cloth screen, which is not only totally devoid of hotspotting, but is also completely acoustically transparent. No holes in this one, it's CLOTH! Complete acoustic transparency, and with the power of his double-stacking setup, effortlessly puts out the gain and the footlamberts. He showed me one pj on all white on his massive screen rather than both, and there was the light level I would expect on such a size - what on a regular sized screen would look like 80IRE gray. But when he kicked the other pj back on and both were showing again, the white was immediately dazzlingly white again, with effortless punch.
The darks were another thing, where I learned some new stuff about contrast ratio. Had not thought of this before.
CRT goes all the way down to complete black, even blacker than movie film.
So when you double-stack a pj sys, of course the whites are all doubled in light level, but aren't the blacks as well? They are on fixed pixel. We still have to conform to the medium the contant was shot in, and most content is still shot on film and transfered to HD. So you can't actually really clamp to black completely when showing something shot on film. You have to conform to the blackness of the film's blacks, or the gamma won't register right.
With the special gamma instrument Cliff has in his signal path, his blacks register accurately right down to the floor. There was an all black scene for a few seconds, and he says, "See that? You can't touch that with fixed pixel." And he's right. Not even close.
What I realized in that moment, of seeing a black that was actually darker than movie film, is that 2 times virtual zero is still virtually zero! Sure, double stacking doubles the whites very obviously, but it does NOT double the blacks noticeably at all. There's an expansion that happens with double stacking CRT tech that is unapproachable in fixed pixel bulb driven. The whites double obviously, whereas the blacks, since they are so dark anyway and thus have almost no light in them at all, double also - but so what? What is virtual zero times 2???
As a result, the contrast ratio on his double stack is phenomenally more than it would be on a single stack of the same pj. The actual contrast ratio effectively gets doubled.
We did several demos, and I was impressed with his system, to say the least. But I still had reservations, for some reason. We put up a nice, tight crosshatch pattern, and I saw the reservation - there had been some drift, and it was impinging on the picture.
We both together set about to redo the image positioning and zone convergence, which is where it had primarily drifted. He is a master of how to do this now that Ken has put everything in place originally, and in short order we had things back to where I thought they had been out of the starting gate. Cliff had just had too many things on his plate before I arrived, to do this especially for me, and I found that quite understandable.
Afterwards, we settled down and looked at some more stuff - Casino Royale especially - then I saw what I had been looking for. We were sitting so close to the screen that it surrounded us, much like the old Cinerama screens did, but I was still able to study the grain of the film used to shoot the movie.
When you are that close and you can do that, you've DEFINITELY got it dialed in!
The precision of everything else we watched that had been currently filmed - the John Wayne stuff, while impressive for that age, just didn't have the high precision of today's stuff - was mesmerizing. I just sat there and stared. I have never seen a screen that big that I could sit THAT close to and still have everything stay razor sharp.
His audio was something else. He put in Matrix II and played the scene where they were being invaded by the bots coming in thru the ceiling, and the sound pressure level was so intense that my hair was chattering, around my face! But no peaks of high bass that can otherwise ruin a high decible sound track. Nope, none of that here. Clean and sizzlingly equalized, so that it could be turned up incredibly high, with no problems at all, just like the 500 watt sound system I used to have in my Mazda RX2. Most people don't know how incredibly high sound pressure levels can get with no hearing damage at all, when the sound is accurately equalized. I used to install high end car stereos, so I know what's possible. Cliff has it nailed, and I don't even know if there is an equalizer in the equipment stack.
Before he opened up the Matrix chapter, I asked him if he was going to install butt kickers. He said, "Reserve that question to after this clip, then ask me that again." After that, there was no need to ask!
This is definitely the best set of HD images I have ever seen. It's the closest thing to ideal one could possibly imagine, it's just freakin' palpable!
My compliments to Ken, and to Cliff for all the little things in between the source and the pj, that also had to be taken care of one by one over the weeks and months - and the learning he had to do over the years - to get to this final result.
And my thanks for his very generous hospitality while I was in the Chicago area.
Check it out if you get the chance, it's worth the drive!
Mr Bob
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