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Author Topic: DCI Audio on the cheap David Buckley Jedi Master Film Handler Posts: 525 From: Oxford, N. Canterbury, New Zealand Registered: Aug 2004 posted 08-12-2014 06:01 PM                        It looks like our little Town Hall may be getting a DCI projection system, but funding for audio is a problem. We're going to have to use an existing audio system with some band-aids. So... a) Is there a processor of lower cost that the CP750 that isn't absolute pants? The film projectors are gone, so its for DCI only. b) Audio looks like being 3.1, ie LCR plus sub. Assuming the processor outputs 5.1, what do I do with the surround channels? Or is this a problem the processor can solve and it outputs 5.1 downmixed to 3.1? I'm hoping that next year we'll get some funding so I can improve matters, so no surrounds may not be a permanent problem. Thanks!  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 08-12-2014 06:27 PM                     What processor are you currently using?  |  IP: Logged Marcel Birgelen Film God Posts: 3357 From: Maastricht, Limburg, Netherlands Registered: Feb 2012 posted 08-12-2014 06:34 PM                     If you really don't want to invest in a Digital Audio Processor, you could try to get a Doremi AUD-D2A, which will convert any "standard" 8-channel AES/EBU signal to 8 discrete analog audio signals and hook it up to some kind of home-cinema amp/receiver/audio processor. Downmixing for the missing channels still needs to be done by the audio processor, but many cheapo home-cinema amp/receiver/processor combos offer those features. Still, it's best to try to get a professional cinema processor from Dolby or Datasat, alongside with somebody who actually knows how to calibrate those things. Why not try the refurb market too? A used Dolby CP650 can be bought for as little as USD 1500. Please note: A CP650 will not downmix your channels, you still need something else for that, like a mixing console with sufficient channels (can also be bought cheap).  |  IP: Logged Tim Sherman Expert Film Handler Posts: 125 From: North Ridgeville, OH, USA Registered: Aug 2000 posted 08-12-2014 06:36 PM                        just go with a USL JSD-60  |  IP: Logged Carsten Kurz Film God Posts: 4340 From: Cologne, NRW, Germany Registered: Aug 2009 posted 08-12-2014 06:51 PM                     Second Hand DTS XD10P can be found for little money as well. Any amps, speakers, etc. already there? You can connect an AUD-D2A to a small mixing desk, around 100US$ for a suitable type, but to do EQ and proper mixdown during daily operations needs a trained operator or a clear 'don't touch it!' statement. I'm currently trying to use a medium-class homevideo receiver in a very minimal DCI setup with LCR only. Seems to work, unfortunately there is no cheap way from 5.1 AES to HDMI, so, for now I need to use an AUD-D2A and discrete analog INs. But it also allows to connect a BluRay Player, etc. without the complications of a mixing desk, and there is a simple cinema processor type master volume control. I payed around 300€ for this Marantz receiver. You can use the internal amps for very small rooms, or use the pre-outs to 'real' external amps. I hope at some point there will be an affordable 6-8ch AES->HDMI audio converter for a full digital solution. - Carsten  |  IP: Logged Harold Hallikainen Jedi Master Film Handler Posts: 906 From: Denver, CO, USA Registered: Aug 2009 posted 08-12-2014 07:02 PM                        Since Tim mentioned the USL JSD-60, I'll second that. It has user-configurable channel mixing (including mixing down to stereo for drive-ins). So, you can pretty much make it do whatever you want. Harold  |  IP: Logged Carsten Kurz Film God Posts: 4340 From: Cologne, NRW, Germany Registered: Aug 2009 posted 08-12-2014 07:10 PM                     Didn't know about the downmix option on the JSD-60. Nice feature. - Carsten  |  IP: Logged Harold Hallikainen Jedi Master Film Handler Posts: 906 From: Denver, CO, USA Registered: Aug 2009 posted 08-12-2014 07:44 PM                        Thanks! We wanted flexibility in channel routing. Working with our DSP guy, we kept coming up with more and more routing options. It just became too much to do with software input select switches. We finally decided to make it generic. Each processing channel gets the sum of products of incoming audio from every input times a mix coefficient. In most cases, the mix coefficient is 1.0 or 0.0, but it can be any floating point number. Pressing a button on the front or through automation just loads the saved mix coefficients for that format. It's working out well, including handling stuff I did not think of. Harold  |  IP: Logged Mark Gulbrandsen Resident Trollmaster Posts: 16657 From: Music City Registered: Jun 99 posted 08-13-2014 01:30 PM                     Yes, the JSD-60 is extremely flexible and I highly recommend it. If you think you might need a little more flexibility in terms of inputs, both analog and digital then the JSD-100 is the way to go. Mark  |  IP: Logged Ken Lackner Phenomenal Film Handler Posts: 1907 From: Atlanta, GA, USA Registered: Sep 2001 posted 08-13-2014 01:34 PM                     JSD-60 was my first thought for new equipment as well. Agreed with Mark's comments about added options on the JSD-100, but it doesn't offer downmixing.  |  IP: Logged David Buckley Jedi Master Film Handler Posts: 525 From: Oxford, N. Canterbury, New Zealand Registered: Aug 2004 posted 08-13-2014 05:28 PM                        Thank you gentlemen for your suggestions. To answer Brad's question, the currently installed processor is "none". The JSD-60 really had me going for quite a while, until I discovered the flaw. Which isn't the boxes fault, but an artifact of the sound system we'll be forced to use, for a while at least, which appears to have reduced in specification since my first post! The audio system will be stereo, with a pair of speakers and a single mono sub, and the sub will need to have the bass end of the crossed over stereo speakers, as well as the LFE channel. The JSD requires (best as I can tell!) that if the screen speakers are biamped, then they are "properly" biamped, not just all the low end mixed to a single subwoofer channel. I see why they've done this with the crossover card, as it means there can be an analogue backup if the DSP quits, which is deviously clever in its own right. But that feature makes it an incomplete solution; I'd need then to manage externally mixing multiple crossed over signals, which isn't the end of the world. But it does look like a good upgrade pathway for the future. Unfortunately, used equipment is out, as the public money funding doesn't permit that. Which brings me to the suggested Doremi AUD-D2A, which looks like the answer, for a while at least. In a similar vein I found the USL DAX-802, are there any pros / cons that make either of this more or less preferable than the other?  |  IP: Logged Harold Hallikainen Jedi Master Film Handler Posts: 906 From: Denver, CO, USA Registered: Aug 2009 posted 08-13-2014 08:04 PM                        If I understand your application, I still think the JSD-60 could do what you want. It sounds like you want to use the LFE for the low end of the screen channels. You can do that my telling the mixer to add L, C, R, and LFE with appropriate levels. The LFE output has the SMPTE specified 125Hz LPF, so high frequency stuff from the other channels won't get out. Harold  |  IP: Logged David Buckley Jedi Master Film Handler Posts: 525 From: Oxford, N. Canterbury, New Zealand Registered: Aug 2004 posted 08-13-2014 10:21 PM                        That is very clever, I didn't get that from the manual or from playing with the windows programming tool. Back on the list then! I guess it will come down to the price difference between the processor and straight DtoA. Later... I've just had a play with the GUI, so I set the config as 5.1 biamp, use the advanced tab mixer to feed multiple channels to LFE, and in the crossover, set it to match the speaker crossover point, and then the high band comes out the standard outputs?  |  IP: Logged Harold Hallikainen Jedi Master Film Handler Posts: 906 From: Denver, CO, USA Registered: Aug 2009 posted 08-13-2014 10:45 PM                        Are you indeed going to run biamp on the screen channels? If not, just select 5.1. The LFE has an LPF in it. Also, all channels have a configurable channel filter (HPF, LPF, BPF, or notch). Harold  |  IP: Logged David Buckley Jedi Master Film Handler Posts: 525 From: Oxford, N. Canterbury, New Zealand Registered: Aug 2004 posted 08-13-2014 11:01 PM                        Yes, I see that now  |  IP: Logged

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