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Author Topic: Looping Non-Sync Audio Source Mark Hajducki Jedi Master Film Handler Posts: 500 From: Edinburgh, UK Registered: May 2003 posted 01-23-2012 07:49 AM                     With the move to digital cinema, are any of the systems able/used to provide the non-sync audio?  |  IP: Logged Frank Angel Film God Posts: 5305 From: Brooklyn NY USA Registered: Dec 1999 posted 01-23-2012 10:57 AM                        Or....you can try totally wireless. Use a Rocketfish transmitter/receiver -- it works on 2.5G transmission, gives you CD quality, and depending on your booth setup, you may only need a few of them, daisy chaining them and using additional transmitter to retransmit where the signal gets lost due to distance. Their range is 150ft transmission (of course given manufacturer's BS, that probably means 100ft). So you probably could get away with using one of the xmitters to feed three, maybe even four screens, then stick in another transmitter. Ground loop problems would be no-existant, but you would have to see how booth EMI affects them, if at all. For a list price at around $70 (but I have seen them on ebay and amazon for $30-$40) it certainly is worth giving them a shot. Clicky here. Even if the booth is huge, you could locate your CD player and the transmitter in the center and get coverage end to end. And if not, if you wanted the CD player to be located at the server, say at one end, multiple transmitters as repeaters would extend the range. This may be a stupid question, but why can't the CDs be uploaded, or "injested" as they say, into the server and programmed exactly like you program the trailers and the feature -- as program lists, but just audio, no image. OR better still, use one of those visualization computer programs to create synchronized color patters to project on the screen (make up for that ugly lack of a curtain) along with the music? Shouldn't a digital server be able to incorporate audio files as any other playable item in a play list? Seems like having a separate CD player and stringing separate wires to each screen system is down-right primative given that you've already got a complete audio/video server playback system designed specifically as a master AV distribution center to feed each booth's projector and audio system. Why even need to switch to external non-sync? Why is there even such a thing as an outboard "non-sync" when you've got digital servers?  |  IP: Logged Dave Macaulay Film God Posts: 2321 From: Toronto, Canada Registered: Apr 2001 posted 01-23-2012 11:55 AM                     Using a server for non-sync is possible but it doesn't fit so easily into the scheduling model: you would have to start the "show" way early with the walk-in music as the first show element. Not a big deal I suppose. Doremi's TMS allows you to set a preshow duration, and then it backtimes the individual server starts from the scheduled showtime pulled from the ticketing system. Probably the other TMS/LMS systems do too; without a TMS you would have to do this adjustment yourself when entering schedules or doing manual starts. Packaging the music for playback might be an issue. I haven't tried but I don't think the server will play a show element that isn't packaged properly - you can't just ingest an mp3 and play it, you have to create a proper DCP package... maybe this isn't rocket science but it isn't trivial. Do the "movietunes" people supply walk-in server content packages? Then what do you do with the lobby? Usually the same music plays in the lobby and as nonsync in all auditoria, all from the same CD player.  |  IP: Logged Scott Norwood Film God Posts: 8146 From: Boston, MA. USA (1774.21 miles northeast of Dallas) Registered: Jun 99 posted 01-23-2012 12:03 PM                        It would be pretty trivial to make a DCP with just the music track, but I have been told that some servers require both picture _and_ track in a DCP (even though this is not actually required by the specification), which means that one would need to make a picture track of all-black frames, which would make for a very large DCP. This would also probably screw up some automation functions (because the automation system will sense that the show is playing, even when it isn't), as well as the timing of show starts. The servers really should have a separate "non-sync music mode" where they can play WAV or MP3 or <insert favorite audio format here> files loaded into a separate playlist without activating the "show running" mode of any automation system that happens to be installed. The Dolby server does not have this function...I don't know about the others. But a $99 CD player is still easier to use and more flexible, especially in a rental situation when the renter of the theatre waks up with a CD and wants it played as walk-in music.. The whole distro amp/hum issue could be solved if the processor manufacturers would use balanced connections for non-sync connections.  |  IP: Logged Alban Birch Film Handler Posts: 63 From: Luxembourg-city , Luxembourg Registered: Jan 2007 posted 01-28-2012 04:42 AM                        Hi I thinkwe're going to do it with the odyssey. The source and transmitter will be in booth 4 and from there we're in two opposite directions, this should be possible? Do we need a receiver in booth 4 or could we just split the signal from the source to the transmitter and JSD-80? Maybe even use the SPDIF from the source to the JSD-80 of booth 4?  |  IP: Logged Harold Hallikainen Jedi Master Film Handler Posts: 906 From: Denver, CO, USA Registered: Aug 2009 posted 02-10-2012 05:02 PM                        I posted info about the Henry Engineering interface previously. As others have pointed out, it's a bit expensive. I just learned of a similar product at a lower price. It's at http://www.mcmelectronics.com/product/MCM-CUSTOM-AUDIO-555-8485-/555-8485 . Harold  |  IP: Logged Tony Bandiera Jr Film God Posts: 3067 From: Moreland Idaho Registered: Apr 2004 posted 02-10-2012 05:15 PM                     Harold, not bad, another useful product, but NOT for this application! Why the hell is everyone trying to re-invent the wheel here? There are ESTABLISHED, PROVEN distribution systems at reasonable cost. Smart (probably have to find used), Odessey, Component Engineering ALL make/made systems that work, are easy to wire and immune to noise. The labor costs of trying to adapt an unproven system to this application, not to mention the cost and hassle of RETURNING gear that didn't work, makes this a beating of a dead horse. Get the right gear for the job, put it in and be done for crissakes. Alban, yes use a receiver for your source booth #4. Trying to split the signal ahead of the system defeats the whole idea of isolation which is what you need to make this work.  |  IP: Logged Harold Hallikainen Jedi Master Film Handler Posts: 906 From: Denver, CO, USA Registered: Aug 2009 posted 02-10-2012 07:15 PM                        Thanks for the comments! Again, I come from a broadcast background where balanced lines and bridging audio inputs are very common. So, this is the way a balanced audio line is distributed in a radio or TV station. I thought it would also be applicable to cinema, but, as you point out, other solutions are available. Again, thanks for the comment! Harold  |  IP: Logged Tony Bandiera Jr Film God Posts: 3067 From: Moreland Idaho Registered: Apr 2004 posted 02-11-2012 02:06 PM                     Harold, I would appreciate a direct answer to one question: In broadcast, do they do what we're trying to do here, which is transmit ONE source to multiple remote locations? (and up to 20 like a cinema would?) My limited experience with broadcast (CBS Studios) has only exposed me to the need to transmit a source or sources to ONE remote location, not daisy-chaining or paralleling to multiple remote locations. And my point is that why try to re-engineer something where cinema-based companies have already done all the legwork? It just does not make sense to me to take that risk. And no offense intended to Alben, but it sounds like he either has limited technical background or does not have ready access to an experienced technician, which would make any "experimental" attempts extra risky. He needs a straightforward, easy to install system with detailed instructions to ensure success. If I were in his country I would gladly go help him with this.  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 02-11-2012 07:50 PM                     One of the big problems was at many event was providing isolated feeds to mulitple news groups and it was always done with direct boxes and some form of distribution amp Op Amp Labs for years made a popular one  |  IP: Logged Carsten Kurz Film God Posts: 4340 From: Cologne, NRW, Germany Registered: Aug 2009 posted 02-11-2012 08:45 PM                     I would do it with active DI-Boxes. Most DI Boxes have loop-through outputs. Very easy to daisy chain them and have a single wire running from source to all processors. All balanced. Very easy to transfer balanced audio over CAT5 cables. That said, the best solution certainly depends on the existing cabling or effort needed to rewire. A simple autostart MP3 flash player today costs 60-100 US$. Could be cheaper and easier to assign one to each screen locally, instead of purchasing a distribution system and rewiring. I guess it's not always the right thing to have the same audio at all screens. - Carsten  |  IP: Logged Harold Hallikainen Jedi Master Film Handler Posts: 906 From: Denver, CO, USA Registered: Aug 2009 posted 02-12-2012 12:56 AM                        Quick answer to Tony... In broadcast analog audio, they used to use 600 ohm sources and 600 ohm terminations in point to point audio circuits. That's still done on very long circuits (many miles through telephone lines in the places this has not been converted to digital). In the 600 ohm days, distribution amplifiers were used to drive separate balanced lines out to each 600 ohm terminated load. Later, they moved to low impedance outputs (50 homs or less) and "bridging" inputs (typically 10k). So a single source could drive MANY bridging inputs. I have no objection to the various other methods presented to resolve the issue. The use of these unbalanced to balanced converters is just one way to deal with it. To me, the big thing is to use balanced lines. Differential or transformer balanced inputs will subtract out the common mode noise (normally power line hum). Thanks! Harold  |  IP: Logged Tony Bandiera Jr Film God Posts: 3067 From: Moreland Idaho Registered: Apr 2004 posted 02-12-2012 12:51 PM                     quote: Harold Hallikainen In the 600 ohm days, distribution amplifiers were used to drive separate balanced lines out to each 600 ohm terminated load. Later, they moved to low impedance outputs (50 homs or less) and "bridging" inputs (typically 10k). So a single source could drive MANY bridging inputs. Ok, thanks Harold, that explains it better. If I am reading this right it sounds like the 600ohm system would be wired in a "home run" type setup, with each load line running individually back to the source, correct? Whereas the later system of 50 to 10k ohms could be wired as a single line with taps off it or as a daisy chain. (Which would be equivalent to the non-sync distribution systems we are discussing.) I worked for Knott's Berry Farm in their tech department and we had some lines which were a few miles from the source for park-wide audio (the music and announcements) and they were all home-runned to a central audio room. They were 600 ohm balanced (mono) lines. I heard but have not confirmed that they have now gone to a digital based distribution system using fibre optic or CAT6 cable and now do stereo.  |  IP: Logged Harold Hallikainen Jedi Master Film Handler Posts: 906 From: Denver, CO, USA Registered: Aug 2009 posted 02-12-2012 01:37 PM                        You've got it! This low source impedance and bridging loads works well for a few thousand feet. With really long lines (phone company provided equalized analog lines), the lines are driven and terminated with a low impedance. It was fairly common to drive and terminate with 150 ohms. The use of the lower impedance (as opposed to 600 ohms) causes more attenuation of the lows which brings it close to the attenuation of the highs. This reduces the amount of equalization required on the line. As I think about it more, even for very long lines, we should be able to drive with a low impedance and have multiple bridging loads (10k) along the line with a low impedance termination at the end of the line. This is the way RS485 data lines work (low impedance transmitters, high impedance receivers, terminations at ends). Interesting discussion. Thanks! Harold  |  IP: Logged

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