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Author Topic: Dolby 3D dual projector setups? Carsten Kurz Film God Posts: 4340 From: Cologne, NRW, Germany Registered: Aug 2009 posted 01-08-2010 04:43 AM                     I heard that recently two large screens in germany have been equipped with dual-projector Dolby 3D systems (Kinoton installations). http://www.dcinematoday.com/dc/PR.aspx?newsID=1652 Someone mentioned to me that these projectors still contain Dolby wheels. Is anyone familiar with this kind of installation, is it 'officially' Dolby approved? Why would they still use filter wheels inside instead of static 'Infitec/Dolby' filters in front of the lens? The only reason I could imagine would be that with filter wheels, both projectors could still be used as single 3D machines temporarily on smaller screens without reinstalls. However my source mentioned that these would not contain standard Dolby wheels but special versions. Still I would think that static filters offer slightly more light - at least if these wheels still have segments and need blanking times. Has anyone heard of Dolby providing static filters for projectors at all? Are they that much different from Infitec Filters? - Carsten  |  IP: Logged Demetris Thoupis Phenomenal Film Handler Posts: 1240 From: Aradippou, Larnaca, Cyprus Registered: Apr 2001 posted 01-08-2010 05:12 AM                     There are two ways to implement a two projector setup. In both cases the desired result is to increase the light output on big screens. One case is to use both projectors showing both eyes. In this case you are mentioning, most probably both projectors are flashing both eye images inside them and thus using the dolby filter wheel prior the light engine. The other case is where each projector shows one eye only thus having projector 1 showing left eye, and projector 2 showing right eye. That is where you use a static filter but I am not sure in Dolbys' case if its inserted prior the light engine or in front as I have never done such a setup myself. Most probably Mark or Gordon or Julio or Steve can inform us better. Demetris  |  IP: Logged Mark Lensenmayer Phenomenal Film Handler Posts: 1605 From: Upper Arlington, OH Registered: Sep 1999 posted 01-08-2010 07:32 AM                     They ran 4-Barco projectors (2 for each eye) using Dolby 3D at the Empire Leicester Square theatre for the premiere in London. Don't know if they are still using them or not.  |  IP: Logged Carsten Kurz Film God Posts: 4340 From: Cologne, NRW, Germany Registered: Aug 2009 posted 01-08-2010 08:11 AM                     Yes, 4 DLP+Dolby 3D for the AVATAR premiere there. But only for the premiere I heard, afterwards they stayed with a 2 projector setup. - Carsten  |  IP: Logged Chase Taylor Expert Film Handler Posts: 175 From: Troy, Alabama, USA Registered: Mar 2001 posted 01-08-2010 10:06 AM                        I believe but could be wrong but when using a BARCO DP-3000 in a dual projector set up the color wheel that goes into each projector is one filter that spins so basically the wheel is not split into two filters just one and each projector has the filter for one eye and the other projector has the filter for the other eye. Someone please correct me if I'm wrong but I think this what I remember how it's done with those.  |  IP: Logged Pete Naples Phenomenal Film Handler Posts: 1565 From: Dunfermline, Scotland Registered: Feb 2001 posted 01-08-2010 12:35 PM                     That is my understanding too Chase, a static filter wouldn't stand up to the heat.  |  IP: Logged Demetris Thoupis Phenomenal Film Handler Posts: 1240 From: Aradippou, Larnaca, Cyprus Registered: Apr 2001 posted 01-08-2010 12:40 PM                     rotating filter with single eye filter  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 01-08-2010 03:14 PM                     I am pretty sure dual projector uses the exact same filters. You have two controllers and one just has to phase them both correctly. Mark  |  IP: Logged Kevin Fairchild Expert Film Handler Posts: 125 From: Kennewick, WA, USA Registered: Oct 2008 posted 01-08-2010 06:39 PM                     Dolby has the Large Screen 3D installation instructions on dolbesecure.com It says that there are two seperate filters. Cat # 932 is the left eye filter. Cat # 933 is the right eye filter.  |  IP: Logged Sam D. Chavez Film God Posts: 2153 From: Martinez, CA USA Registered: Aug 2003 posted 01-08-2010 08:33 PM                       Kevin is correct.  |  IP: Logged Demetris Thoupis Phenomenal Film Handler Posts: 1240 From: Aradippou, Larnaca, Cyprus Registered: Apr 2001 posted 01-09-2010 01:40 AM                     After reading thoroughly via the Dolby Extranet, it says that they are static filters although they implement colour wheel like the standard solution so they are placed again prior the light engine. The BIG difference is that the images are not flashed at all as they are shown without any gaps as each projector shows one eye only so the brightness is much higher. Demetris  |  IP: Logged Kris Verhanneman Expert Film Handler Posts: 182 From: Belgium Registered: Dec 2009 posted 01-09-2010 06:33 AM                     Much higher? How long do we project 'black' between a flash of image? Anybody who can say how much (%) that is?  |  IP: Logged Julio Roberto Jedi Master Film Handler Posts: 938 From: Madrid, Madrid, Spain Registered: Oct 2008 posted 01-09-2010 07:14 AM                    Aprox. 7% Per projector. So in this case, they get a 14% increase in light, compared to fitting both projectors with traditional filters. Of course, having two projectors already "doubles" the light output to begin with.  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 01-10-2010 03:22 PM                     I never thought of that aspect. Either would work but one is going to give lots more light.  |  IP: Logged Mark Uhde Film Handler Posts: 9 From: Kalispell, MT USA Registered: Jul 2009 posted 01-19-2010 12:53 AM                        Sorry Julio, that math is wrong. You can't add the light loss from each projector to get the total. You have to average it. Since each one is, by your numbers, losing about 7% the average is also about 7% of the total. To demonstrate why you can't add it, imagine a hypothetical 15-projector setup. If you added up the 7% loss in each projector to get total loss, you would be losing 105% of your light  |  IP: Logged

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