Film-Tech Forum ARCHIVE: Sound Processors for D-Cinema

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Posted by Ian Bailey (Member # 1752) on 10-02-2006, 06:45 AM:

What Sound Processors are being used in D-Cinema installations?
Are there any processors in use today that could not be used for D-Cinema?
Cheers Ian

Posted by Mark Gulbrandsen (Member # 72) on 10-02-2006, 07:50 AM:

There are two primary processors being used. CP-650 and the USL JDS-80 and it sister processor from DTS. Both have the option of having an SPDIF digital input. With the addition of an external D to A such as the DMA-8 and others such as the RAMSA outboard unit you can utilize any processor with an aux. 6 channel input.

Mark

Posted by Ian Bailey (Member # 1752) on 10-02-2006, 07:58 AM:

Mark
Do you mean a "stereo input that is processed to 6 channels" when you say "an auxillary 6 channel input"?
Ian

Posted by Paul Konen (Member # 41) on 10-02-2006, 10:00 AM:

Ian, I have installed a USL JSD-80 and am using the AES/BSU digital audio input. It is a DB-25 connection. I'm not sure if there is an optional component that you have to order in order for the processor to decode the digital data.

I selected the digital audio input, because I had a slight ground loop using the analog cable.

Posted by Chris Trainor (Member # 9) on 10-02-2006, 11:24 AM:

Ian,

the input needs to be 6 discreet channels. L/C/R/lS/rS/Sub.

Which basically prevents you from using regular non-sync inputs.

--Chris

Posted by Bobby Henderson (Member # 840) on 10-02-2006, 01:41 PM:

I thought most audio setups able to handle DTS, Dolby Digital & SDDS could accomodate the LPCM surround format of digital cinema.

Does this mean the Dolby CP-65 and Smart processors at our local Carmike will get replaced when their Christie CP2000 systems get installed?

Posted by Scott Norwood (Member # 30) on 10-02-2006, 01:57 PM:

If the DLP system provides analog outputs, they can easily be connected to the format 10 input on the CP65. This would preclude using a DA20 as well, though, unless some sort of switchbox is installed.

Does the DMA-8 connect to the format 10 input and, if so, can it accommodate an installation with an existing DA20?

Posted by Pete Naples (Member # 761) on 10-02-2006, 02:01 PM:

Scott.

Yes to both questions, and it works very well.

Posted by John Hawkinson (Member # 1135) on 10-02-2006, 03:38 PM:

If you don't need the DA20 to switch automatically or under automation control (unlikely unless you're running digital cinema with an analog backup simultaneously), you can connect connect up to the CP200 passthrough input of the DA20. When the DA20 is off, the passthrough is connected to the CP65.

--jhawk

Posted by Michael Schaffer (Member # 1204) on 10-03-2006, 02:20 AM:

Scott - when you install a DMA8, the existing external 6-channel from a DTS processor or DA20 is routed *through* the DMA8 and can both be manually and remotely switched.

As has been mentioned before, some digital cinema servers, like the Doremi used in the Christie/AIX installations, can also provide analog 6-channel out. Then you don't need the DMA8 and with the help of an interface board with relay-switchable inputs, you can automatically switch between d-cinema and digital sound on film.

Posted by Ian Bailey (Member # 1752) on 10-03-2006, 03:54 AM:

Bobby
That was exactly my thoughts when I posted this question.

I have a variety of processors(CSP1200,JSX1000,Smart Mod 6,DTS6AD,USL105/195,CP65 soon.........can all these accept the analogue 6 channel input? or do we just throw all these onto the pile of platters when D-Cinema fully takes over.

Which processors cannot accept the analogue 6 channel input?

Will the new breed of D-Cinema processors sound so much better that we will have to use them?
Cheers Ian

Posted by Cameron Glendinning (Member # 3516) on 10-03-2006, 06:54 AM:

Well it wont be hard to beat the current dolby digital standard, lets hope they get the bit rate up a bit, perhaps up to cd standard?

I feel that this question is a bit premiture as I haven't even come across the idea that digital servers are standardised yet.

As for raw digital output perhaps a home processer could do the processing. Perhaps its just a case of switching the sound card in the server to an analogue one ect (just think computer)

The current 6 track input with the 25 pin D conecter ( I have already posted a DIY make your own cable for DVD 5.1 in one of these forums ) might be all that you need.

One things for sure the EQ, Amps, and speakers wont have to change

Posted by Larry Zuverink (Member # 1483) on 10-03-2006, 07:34 AM:

But some of the show players have 6 channel analog output so a DMA8 will not be needed.

Posted by Lyle Romer (Member # 1266) on 10-03-2006, 09:18 AM:

quote: Cameron Glendinning
Well it wont be hard to beat the current dolby digital standard, lets hope they get the bit rate up a bit, perhaps up to cd standard?

Digital Cinema audio is the one really good thing about the format. It far exceeds CD standard. As specified, it will be uncompressed 24 bit at either 48k or 96k samples per second (CD is 16 bit, 44.1k samples per second). It can also support up to 16 channels which can't be handled by any current processor that I know of.

It would be cool if somebody who has the knowlege could make a little chart in this thread detailing every sound processor, if it can handle digital cinema and what is needed to interface it. Example:

Processor..Support..............Interface
...........................Digital...............Analog
CP-65........Yes......DMA-8.............None Required
CP-100
CP-200
CP-50
CP-55
CP-500.......Yes......DMA-8.............CAT685 Installed
CP-650
Panastereo CSP1200....DMA-8.............None Required
USL JS 6 channel series DMA-8...........None Required
Smart Mod 2C..........DMA-8.............None Required
Smart Mod5............DMA-8.............None Required
Smart Mod7............DMA-8.............None Required
DTS 6AD...............DMA-8.............None Required
Smart Mod VI..........DMA-8.............None Required

I don't know all the panastereo, Smart and usl processors so I'll stop my list here.

[ 10-03-2006, 10:36 PM: Message edited by: Lyle Romer ]

Posted by Paul Konen (Member # 41) on 10-03-2006, 09:42 AM:

Ian, the analog is "standard" pinouts. Meaning, I was able to place it into my CP500 first, and then moved it down to my JSD-80.

Lyle - CP-500 needs a DMA-8 if you want to process AES/BSU digital audio.

Posted by Lyle Romer (Member # 1266) on 10-03-2006, 11:11 AM:

Paul- Does the CP-500 need an option card for 6 channel analog input?

I guess if people post info, I'll just update the chart in my post.

Posted by Dave Macaulay (Member # 813) on 10-03-2006, 01:01 PM:

The CP500 needs the CAT685 analog input card for 6-channel input.

Posted by Gordon McLeod (Member # 33) on 10-03-2006, 05:22 PM:

The Panastereo CSP1200
The USL JS 6 channel serries
Smart Mod 2C
Smart Mod5
Smart Mod7
DTS 6AD
to name a few that have analogue 6 channel inputs

Posted by Dustin Mitchell (Member # 372) on 10-03-2006, 05:32 PM:

I believe you could add the Mod VI to Gordon's list. We have 2 digital screens that utilize those with no additional cards/equipment.

Posted by Martin Brooks (Member # 1269) on 10-03-2006, 09:21 PM:

quote: Lyle Romer
It far exceeds CD standard. As specified, it will be uncompressed 24 bit at either 48k or 96k samples per second (CD is 16 bit, 44.1k samples per second).

The strange thing about this is that almost every time I've seen D-Cinema, I've thought the sound was inferior to Dolby Digital or DTS. It seems like it had the same problems as early CDs: harsh and brittle sound with no warmth.

Posted by Bobby Henderson (Member # 840) on 10-03-2006, 09:35 PM:

That probably gets back to that old "keeping the auditorium in tune" kind of thing. The audio chain rarely gets any attention at all these days in commercial theaters, which I find very shocking. 5.1 surround sound is very common in the living rooms of many millions of Americans. They know when the theater is sounding shitty and wimpy. It reinforces that "my home system is better than this crap" sort of mindset.

One must also consider the issue that a major dollar investment is happening in the projection side of things, but very often whatever audio hardware was in the booth, up on the walls and behind the screen would stay. Even if it was crappy.

Posted by Cameron Glendinning (Member # 3516) on 10-03-2006, 09:51 PM:

quote:
quote: Lyle Romer It far exceeds CD standard. As specified, it will be uncompressed 24 bit at either 48k or 96k samples per second (CD is 16 bit, 44.1k samples per second).

I'm assuming that this is the new standard? Is it smpte? will dts be releasing a higher quality version of Digital Cinema sound?

As for the current 35mm it is very compressed? Dolby Digital averages 14 to 1, and is basically mp3 ( DTS averages 3 to 1 and I believe twice the bitrate )

I also believe that it is impossible to record 5 individual full bandwidth channels (say a mono orchestral works on each channel) the Dolby digital system cannot cope with this like say 70mm could..

To me 35mm Dolby digital is an extremely impressive effort done with smoke and mirrors. perfect it isn't.

Gordon I would love your opinion on this

Make your own 6 channel input cable

Channel allocations for the 25 Way digital D connectors

Pin 2 - Right Surround
Pin 14 - Left
Pin 15 - Left Surround
Pin 17 - Right
Pin 20 - Centre
Pin 24 - Sub Bass

Pins 1, 3 to 13 are all GNDs

I believe its best to have one common earth.

Posted by Lyle Romer (Member # 1266) on 10-03-2006, 10:43 PM:

quote: Cameron Glendinning
I'm assuming that this is the new standard? Is it smpte? will dts be releasing a higher quality version of Digital Cinema sound?

This is what is specified in the DCI spec. There won't be any DTS, Dolby Digital etc with digital cinema. There is no need. It's just an uncompressed PCM bitstream.

As for current 35mm, Dolby Digital is closer to 20:1. DTS is 4:1. I don't know what the Dolby AC-3 codec would do if you put a the same mono recording of an orchestra on all 5 channels. The codec was designed for movie and TV soundtracks so I don't think that was the intended application. Considering the compression level and the fact that AC-3 was developed in the early 90's it sounds pretty impressive.

As for D-cinema audio, I've actually noticed how much better it sounds than any 35mm digital system. I think the poor sound others have reported is due to B-chain issues. The theaters I have seen D-cinema in have all been THX or formally THX auditoriums. I noticed the sound quality before I knew it was uncompressed.

Posted by Paul Konen (Member # 41) on 10-04-2006, 09:20 AM:

Yeah, what Dave said above. [Big Grin]

Posted by Bobby Henderson (Member # 840) on 10-04-2006, 10:06 AM:

The theatrical Dolby Digital bitrate is 320 kilobits per second, well below the 448kb/s rate typically seen on DVD. The theatrical DTS format runs at 820 kilobits per second, but uses an older APT-X waveform codec that isn't as efficient as the DTS CAC codec used in the DVD format, which typically runs at 754kb/s.

It is clear both Dolby and DTS are looking almost exclusively toward home audio formats on optical disc, games, computers and portable devices for their current and next generation audio formats. Those are areas where audio compression still has a relevant need. There's little to no relevance for it in digital cinema.

There is little if anything to indicate Dolby will try to deploy Dolby Digital Plus or Dolby True HD into commercial theaters at all in either film-based or video-based formats. The same goes for DTS with its DTS-HD format. About the only thing I can see emerging at all is perhaps some implementation in IMAX or other large format film-based special venue theaters. But even there one could simply synch up the film print to a hard disc system playing back fully uncompressed 5.1 channel 24/96 audio.

Basically put, audio compression systems for movie theaters is now a dying thing -even if those systems have memorable brand names and fancy format trailers. Someone will just have to come up with something catchy for 20-bit or 24-bit 5.1 LPCM.

Posted by Jarryd Beard (Member # 2543) on 03-03-2007, 03:13 PM:

We have the JDS-80 in place with two of our digital systems. Recently, one of the units began powering up in SR instead of non-sync mode. I looked at the preliminary manual in the manuals section, but the PDF only contains the first ten pages. How might I change the setting to power up in non-sync?

Posted by Dustin Mitchell (Member # 372) on 03-03-2007, 07:44 PM:

Jarrynd, you should probably start a new thread as you problem likely has nothing to do with the fact your processor is outputting to a digital system.

In the meantime, has any work been done on the processor since it started doing this? Were any cards changed/anyone messing around in it? I don't know anything about that particular sound processor but I do know that often times there things ('wake up' format) are determined by a jumper inside the processor.

Posted by Jarryd Beard (Member # 2543) on 03-03-2007, 08:24 PM:

Sorry about that. I guess this was a bit off topic. To continue the discussion in regards to the JDS-80 and non-sync sound, go to this thread.

Posted by Gordon McLeod (Member # 33) on 03-04-2007, 09:20 AM:

Cameron said "Gordon I would love your opinion on this

Make your own 6 channel input cable

Channel allocations for the 25 Way digital D connectors

Pin 2 - Right Surround
Pin 14 - Left
Pin 15 - Left Surround
Pin 17 - Right
Pin 20 - Centre
Pin 24 - Sub Bass

Pins 1, 3 to 13 are all GNDs"

It would depend on the pin allocation of what you are connecting to
Also some devices have a balanced input