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Author Topic: Audio Description and 7.1 Sound Marco Giustini Film God Posts: 2713 From: Reading, UK Registered: Nov 2007 posted 06-25-2015 03:26 PM                     Yes, it is saying that Digital 2 is being used for HI/VI and the sound routed to AUX 7/8. It does not say that that only works when in 7.1 mode! You said the AD was working when in 5.1 mode and not when in 7.1 mode. That setting is not supposed to be touched, it is set during installation and depends on how the sound processor is wired by the installer. Once it's been set, it works, in any format.  |  IP: Logged Michael Sharples Film Handler Posts: 12 From: Leeds, West Yorkshire, England Registered: Jun 2015 posted 07-01-2015 10:47 AM                        Just ran the dolby 7.1 test dcp from FreeDCP.net. Definately getting 7.1 channels, but as per the picture, AD is only available for 7.1 via digi 2. We use digi 2 for the satelite so this setting will need to be changed depending on what we are screening.  |  IP: Logged Marco Giustini Film God Posts: 2713 From: Reading, UK Registered: Nov 2007 posted 07-01-2015 11:07 AM                     Just use DIG 3! That setting you mentioned is NOT supposed to be touched once the system has been installed. Leave the system as it is in 7.1 with AD on DIG 2 routed to AUX 7/8 and use DIG3/DIG4 for your needs.  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 07-02-2015 05:29 AM                     If you have to use the CP750 as an AES audio switcher and all four inputs are taken...you can use an D/A converter including USL's DAX-202 to handle just the ADA stuff. If the Toslink input is available, there are cheap coax to toslink converters too.  |  IP: Logged Michael Sharples Film Handler Posts: 12 From: Leeds, West Yorkshire, England Registered: Jun 2015 posted 07-02-2015 01:46 PM                        Thanks, i'll look into the D/A converter option as we currently use all four inputs inc. the toslink. M  |  IP: Logged System Notices Forum Watchdog / Soup Nazi Posts: 215 Registered: Apr 2004 posted 11-21-2017 06:59 PM                 It has been 873 days since the last post.  |  IP: Logged Rollins Brenton Film Handler Posts: 1 From: Kapaa, Hawaii / USA Registered: Nov 2017 posted 11-21-2017 06:59 PM                     Sorry for necroing this post but I am having kind of the same problem. Had smpte coming from back speakers and would have to turn back speakers off. We upgraded to USL UPC-28C. We were told by a dealer we had to get a breakout box from 16RJ-7.1-DRM-SNY the cp750 to connect to the USL UPC-28C. Well, that got rid of the AD coming from the back speakers. I also upgraded the cp750 to the latest firmware. It seems we have 7.1 now as I can hear the sound effects and movies from all around. I cannot for the life on me get AD back and working which is probably the breakout box 16RJ-7.1-DRM-SNY. I see people saying use digi2, would that require me to get a bnc to speaker wire cable and hook that up to the USL UPC-28C. Any help would be appreciated. I can post pictures if needed  |  IP: Logged Harold Hallikainen Jedi Master Film Handler Posts: 906 From: Denver, CO, USA Registered: Aug 2009 posted 11-21-2017 07:16 PM                        The CP750 started as an 8 channel processor, so you could do 7.1 OR VI, but not both. But, several years ago, they did a firmware upgrade that let you use 8 channels of the Digital 1 input while simultaneously sending the Digital 2 input to the CH7/CH8 RCA connectors. As I recall, the Digital 2 input is unbalanced, so a transformer is required to take AES/EBU pair 4 from the server and drive the Digital 2 input. I imagine Dolby makes a board that includes the transformer and does the appropriate routing such that server output channels 7 and 8 end up on the Digital 2 input, and sever output channels 11 and 12 end up on the CP750 channel 7/8 input. The end result is 7.1 audio from the digital 1 input ending up on the main analog outputs. The server output channels 7 and 8 (AES/EBU pair 4) go through a digital to analog conversion between the Digital 2 input and the CH7/CH8 outputs. These outputs can drive the IRC-28C. For the HI input of the IRC-28C, you can use either the HI output of the CP750 or the CH7 output. The HI output is generated in the CP750 and will always be present no matter what the content is. The CH7 output is HI delivered in the DCP, but not all content has an HI track, and not all content is DCP. Therefore, I think it's generally better to use the HI output. The CH8 output can drive the VI input of the IR-28C. I ASSUME there is an adapter that handles the required split of AES/EBU and provides the transformer for driving the digital 2 input. Does anyone know where to get this? Thanks! Harold  |  IP: Logged Sam D. Chavez Film God Posts: 2153 From: Martinez, CA USA Registered: Aug 2003 posted 11-21-2017 08:01 PM                       Odyssey has such dongles available.  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 11-22-2017 06:39 AM                     A couple of corrections. Yes, the CP750 came out as an 8-channel processor BEFORE 7.1 so AES Pairs 1-3 would come out of the Main output and pair 4 could come out of the Aux 7/8. WHEN 7.1 came out, the software update came out with it to allow all 8 channels to be used on the 4xAES input and output and usurp Digital 2 as the D/A decoder to feed Aux 7/8. On the General Settings Tab of the CP750 set up software, you can configure the CP750 as a 5.1 or 7.1 processor and how to decode it. You can tell the CP750 that you will use an external AES decoder and merely mute Aux 7/8 or that you want to use the Digital 2 decoder. Harold is correct that Digital 2 is an unbalanced input (AES3-id) so you should convert AES3 (balanced 110-Ohm to 75-Ohm unbalanced). It being a BNC type input implies that it is looking for a 1V nominal signal too. Odyssey does make a board for the CP750 that will allow one to run two RJ45 (CAT) cables (and when they are carrying AES audio, they are supposed to be shielded, by the way) to the CP750 and it will break out pair-4 to a terminal block (it is selectable to be pair 4 or pair 8). You then have to convert it, as mentioned above to the proper impedance and go from balanced to unbalanced. In the Odyssey documentation, they show one merely taking an ordinary video cable and cutting an end off to jam the wires to the + and - terminals (no conversion). I have complained to Odyssey about this "design." I believe, now, that Odyssey has a proper transformer option that will take you from BNC to a terminal block so you just have to run a pair of wires a few inches. (The transformer part gets attached to the CP750 via the BNC. Canarie has in-line transformers that can do the job that have XLR inputs and BNC outputs. Canarie also has a version that has a 10dB pad in it to get the voltage into the proper range. They work fine if one is using conventional AES cable but are a bit bulky/heavy to break out typical CAT cable pairs. Another option that Odyssey has, if the server has a normal pin configuration on the DB25 connector (e.g. a Dolby DSS configuration) is a breakout board that will divert pair 4 to an RJ45 connector and let the rest pass through (it is a small board with a male/female DB25 and the RJ45 between them). You then run an ordinary CAT cable to the sound rack where they have another module that is RJ45 in and BNC out (again, it connects directly to Digital 2). It takes pair 4 (the white/brown and Brown) and sends it out of the Coax.  |  IP: Logged

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