Dolby CP650 A/D (5.1) Conversion

[Paul Finn]

The SR-D (and DTS) processors MUST be programmed for the correct 'offset code' for picture-sound sync, regardless of the reader location. The usual correct setting could be modified to adjust for other audio delays in the system.

Paul Finn

[Sascha Roll]

Well, so what are you going to do in case of a Fallback from SRD/DTS to analogue sound?

[Pete Naples]

We (Omnex in the UK), designed and manufacture an automatable switch box which caters for A/B switching of balanced sources to amplifiers. It became necessary when there is a D Cinema Processor in use with no multi-channel analogue input for 35/70mm.

[Ioannis Syrogiannis]

Well, so what are you going to do in case of a Fallback from SRD/DTS to analogue sound?

Indeed, that is a valid question. One can't make sure that all parts of all films are well read on digital. And I don't know of any way to introduce delay on the SR sound on the CP650.
(The equipment that follows, though, for example, the Q-SYS core can do better on that field.)

I would suggest one to determine the delay introduced by the chain of equipment and then examine how much to move the reader.
My guess was that the reader is both for SR and SR-D. The example I gave, of the SR-D reader being before the head, was to say that we don't need to take the reader's position for granted.

[Sam Chavez]

Maybe I missed something in this thread, but you are pretty well stuck with the physical location of analog optical pick up or reader. You can move the digital reader as needed and set the delay accordingly but there's no adjustment for delay provided in your normal cinema processor. There was a combination reader made by a couple of companies but they were frightfully expensive and long gone.

[Pete Naples]

Arvus used to make one, which I used on one install to get analog multi-channel audio into a CP950 via its HDMI input. But it wasn't cheap, and I can't find any mention of it on their website now.



The Trinnov OV2 has a 5.1 analog input set, but no HDMI inputs, which pretty much rules it out for home theater applications.

Leo, a simple HDMI de-embedder takes care of that. I have installed many this way.

Datasat AP25 has HDMI, 35mm optical and multi-channel analogue.

But none of those will take care of the domestic immersive formats.

[Steve Guttag]

A simple HDMI de-embedder? To what? 2-channel? Or, perhaps a multi-channel one? Please, there isn't near enough sophistication in one of those to deal with the possible channel differences. What could be added to an OV2 would be an Extron SP200, if you want to keep it all professional with legitimate integration. The SP200 will handle up to consumer Atmos (and DTS-X) plus all of the lesser formats and output them analog for the OV2's analog inputs.

Naturally, QSYS, via the DCIO-H will handle much of the HDMI offerings but not Dolby high-bit-rate stuff like TrueHD or Atmos.

There is also the possibility, though I hate it, to use consumer home theatre AVRs (they always seem to have issues, are short lived and take up an obscene amount of space in a rack. Of course, if one likes the Harman piece, you could get the original before it is rebadged JBL...Trinnov Altitude. Also Hellish Expensive. But hey, it will do far beyond typical consumer Atmos.

Fortunately, in commercial cinemas, if I need an Atmos decoder for an Atmos room, the DCP Atmos decoder (e.g. IMS3000 or CP950A...etc.) can handle the consumer formats too...but they don't do DTS (popular on Blu-rays). Most/all Blu-ray players will handle decoding DTS or Dolby True HD into PCM (it sort of begs the question why they bother with DTS or Dolby except maybe to save space on the media) as most would rather have LPCM. Only for the immersives does the encoding seem to buy more than 7.1 audio. A down side to letting the player decode the audio, however, is that 2-channel encodes (including mono on both Left and Right) will be sent to the sound system that way rather than as a pro-logic decoded audio to get a center channel (or surrounds, if Lt/Rt). Straight up Left/Right to a cinema, where the speakers are very wide, sounds bad/odd.

[Joseph Re]

Again thank you all for the responses. I am still discussing with the customer the possible solutions.
One that seems to make the most sense is replacing the exsiting AudioContol X9s pre-amp with something that has assignable analog inputs - such as a Storm Audio Core16.
I posed a question to my Storm rep regarding converting the XLR cabels (from 650) to analog RCA for input on the Storm pre. I am awaiting a response, but from everything I have read, this should work without issue.

That said, the customer has a "buddy" who gave him some advice. Maybe you can read below and see if any of it makes sense (at your convenience). Thanks again!
(the fact the guys says 'meh' regarding a Storm Core16 makes him suspect at best, IMO

---------------------------
How’s your electronics skills? There are a million ways around that, but it takes some skills.

First, forgot those crazy 20k datasat processors. I looked at them but meh.

Get a ‘pre processor’ for digital this is what i have:

https://www.ebay.com/itm/355156888706?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=pjrbecloqxw&sssrc=4429486&ssuid=MqlM_8ED Sh S&var=&widget_ver=artemis&media=COPY

Older versions are even less $$$

Then, take both balanced line outputs from the cp650 and the preprocessor and literally just switch them. Electrically. However you are comfortable.

I used this:

Electronics-Salon 8 Channel 10Amp SPDT Power Relay Module Board (Operating Voltage: DC 12V) https://a.co/d/9zWhGuD

Tie one side to NC, the other to NO and go out the common.

The pro way is to get at least a 12x12 audio switcher:

https://www.ebay.com/itm/276228430049?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=QHxy-xnjTqK&sssrc=4429486&ssuid=MqlM_8EDShS&var=&widget _ver=artemis&media=COPY

You are only switching the 6 channels the cp650 supports. Atmos stays direct to digital side.

You can get out the door for $2500 with srd and full single switch back and forth.

You feed just power amps like in the theaters. You can buy a consumer amp and back feed it but i like the big dogs.

If you didn’t care about the atmos, you could also use a DMA8 plus, to feed the digital into the cp650, but i didn’t like this. I prefer what i did above.

https://www.ebay.com/itm/276214561187?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=qOyoRdGBTsa&sssrc=4429486&ssuid=MqlM_8ED Sh S&var=&widget_ver=artemis&media=COPY

The latter is cheap and easy though, you just loose your atmos.

Assuming the above: Then, just get a digital reader for srd.

https://www.ebay.com/itm/304755783718?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=PYOgKlg4RPC&sssrc=4429486&ssuid=MqlM_8ED Sh S&var=&widget_ver=artemis&media=COPY