Film-Tech Forum ARCHIVE: DRIVE-IN THEATRES dual digital

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Posted by Allan Barnes (Member # 5178) on 06-24-2018, 02:15 AM:

Are there any indoor or drive-in theatres using TWO DIGITAL BARCO PROJECTORS linked together to show the same movie on the same screen at the same time - goal being to double light on the screen. We are on SINGLE PHASE POWER and have an unused backup projector.

I think I read here about 3D indoor shows doing something like this?

Posted by Steve Guttag (Member # 268) on 06-24-2018, 09:38 AM:

Yes, it can certainly be done though, nowadays, using Laser based projectors is often the preferred, and, often lower cost option (both to buy and the cost of double lamps (high power).

Posted by Marcel Birgelen (Member # 6801) on 06-25-2018, 12:32 AM:

For 3D it is a no-brainer, since the images of both projectors don't need to be perfectly aligned.

For 2D, it's a pretty though cookie, since you need to align both pictures perfectly to avoid a mess on screen.

Even if you manage to align both pictures perfectly, it will be a constant battle to keep both projectors aligned. Even something simple as a format switch can bring them out of alignment easily.

Christie has a solution called "Christie Duo", it works with a limited set of their projectors and uses a camera and software that continuously re-calibrates the projectors. Unfortunately, Barco doesn't offer any out-of-the-box solution for this.

There's also some little hack I've applied in the past in a non-DCI setup, where I simply wasn't able to align two projectors perfectly and I also didn't have blending software/hardware to compensate for this:

- Choose one projector to be your "sharp image" projector: Max-out the brightness of this projector and make sure the picture is as sharp as possible.
- Choose one projector to be your "blurry image" projector: De-focus the image a bit, so the result is a pretty blurry image. You're aiming at a "with" of roughly 2.5 pixels. Also, take the brightness of this projector down to roughly 80%.

The resulting image will still have some artifacts, but they'll be greatly reduced compared to two identical images imperfectly overlapping each other.

Posted by Mark Gulbrandsen (Member # 72) on 06-26-2018, 11:03 AM:

I installed 4K projectors at two of the DI's that I have been servicing. Both have 100+ foot wide screens and both have brighter images than many indoor theaters have. They can also start about 40 minutes earlier than most.

quote: Marcel Birgelen
Christie has a solution called "Christie Duo", it works with a limited set of their projectors and uses a camera and software that continuously re-calibrates the projectors. Unfortunately, Barco doesn't offer any out-of-the-box solution for this.

Sounds like a version of the Imax two projector auto-alignment system that also utilized Dual Christie projectors.

Mark

Posted by Stephan Shelley (Member # 8587) on 06-27-2018, 02:40 PM:

I know that Alamo Draft House has done dual Sony projectors. They use both for 2D and 3D.Sony also make a camera and auto alignment program but has been found to produce less than desirable results. The New Mission's screen 1 is such an installation.

Posted by Carsten Kurz (Member # 5396) on 06-27-2018, 05:19 PM:

Brave little Stephan... you mention 'Sony' immediately following a Gulbrandsen posting?

Woooooooooooooooooohhhhhhhhhhhhh.........

- Carsten

Posted by Mark Gulbrandsen (Member # 72) on 06-27-2018, 06:50 PM:

Posted by Carsten Kurz (Member # 5396) on 06-28-2018, 07:41 AM:

Mark, I know I am under fire here, but - there are a few locations that actually use a 4-stack Sony 515 for daily operations.
That is, 24UHP lamps running for a single screen.

Stacks of 6 machines have been used on special occasions, e.g. premieres, 4 regular, 2 fallback - but continuously driven (dowsers closed)

- Carsten

Posted by Dave Macaulay (Member # 813) on 06-28-2018, 07:50 AM:

Alan - interesting idea.
I have noticed that Dolby DSS servers have a place to assign a primary and secondary projector address - I guess you set it up as if it was two projector 3D, and 2D send the same image to both projectors? (How could you get four with the same image though?)
I think you would want relatively identical projectors, or at least both S1 or S2?

Posted by Stephan Shelley (Member # 8587) on 06-28-2018, 01:42 PM:

Ah not so little anymore.

I was not praising Sony just saying there are places doing it. If one has to do it for 2D the projectors must have a light issues and the ones I know about at the New Mission have 6 UHD bulbs in them. Personal I am not a fan of the Sony's.

Now I am going to get into trouble because NECs have there light issues as well. What I could do with a Christie M with an 1800 watt bulb takes a 3K on a NEC and I am not talking about a 3K standard cinema bulb but a proper DC bulb for the NEC.

Posted by Carsten Kurz (Member # 5396) on 06-28-2018, 02:19 PM:

Now, first you mention Sony, then you put down NEC - THAT'S begging for trouble ;-)

Posted by Marcel Birgelen (Member # 6801) on 06-29-2018, 03:58 AM:

quote: Dave Macaulay
I have noticed that Dolby DSS servers have a place to assign a primary and secondary projector address - I guess you set it up as if it was two projector 3D, and 2D send the same image to both projectors? (How could you get four with the same image though?)

Sony has offered dual stacking options as a standard for a while now. The quoad and hexa-stacking options aren't industry standard, but since it involves showcase scenarios probably came with some special support from Sony.

The more projectors you stack, the more you need to converge the image on screen. It almost brings back the old CRT projector days, where you could have a full-time job trying to keep an array of them converged...

Posted by Mark Gulbrandsen (Member # 72) on 06-29-2018, 01:41 PM:

quote: Carsten Kurz
Mark, I know I am under fire here, but - there are a few locations that actually use a 4-stack Sony 515 for daily operations.

Sony HAS TO OFFER stacking options because their projectors can barely light up anything more than a 40 foot wide screen and they even struggle just to do that. You would have to be a serious Sony die hard to want that much LCOS crap to tolerate in your booth. And better buy many spare LCOS chips cause you'll be replacing the green chips pretty often.

Still though, the best video image I have ever seen projected was with an early Sony HD CRT projector on about a 30 foot wide screen. It was fed an analog HD signal. This was at a SMPTE meeting in Chicago that was held at Allstate Insurance. It was the best image of the show up until I ran the Ultimatte demo film on my 1939 cast iron Century C. Then, after I ran the film for Ultmatte the Sony engineers swarmed my projector wanting to know "why it look so good".

Mark