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Author Topic: DVD via AES/EBU into CP650 Adrian Steiner Film Handler Posts: 18 From: Baar, Switzerland Registered: Dec 2002 posted 04-28-2003 04:52 PM                     I read the thread about connecting a DVD Player to a DA20 + CP65 here . But how about connecting a DVD Player to a CP650? The Installation Manual says (on page 1-6): "Format 80: External Digital Input This external digital audio format can carry up to six channels (L, C, R, Ls, Rs, SW) and is input via an AES/EBU bitstream connected to the rear-panel Option Card I/O connector (see table A-2 in appendix B). The bitstream can be PCM or Dolby Digital encoded." So could one connect the S/PDIF output of a DVD player to a S/PDIF -> AES/EBU converter and that to the CP650 to get 5.1 surround? Does "Dolby Digital encoded" mean the consumer DVD player format or the one for the cinema (or am I mixing up things from the CP65 + DA20 thread)? BTW: Why is on the inputs & control wiring diagram (page 2-9) the AES/EBU input described as "Non-Sync source, with 2-channel AES/EBU Digital output (Format80)"? Why 2-channel nonsync? Is AES/EBU really two nonsync signals and not one symmetric signal? Cheers, Adi  |  IP: Logged Michael Schaffer "Where is the Boardwalk Hotel?" Posts: 4143 From: Boston, MA Registered: Apr 2002 posted 04-29-2003 03:31 AM                        It simply means that you can input a 2-channel digital input source here. I think you are confusing non-sync and symmetric. In English symmetric audio connections are called "balanced". Balanced means that you have 2 signal connections for one signal which are mirrored at 180 degrees relative to each other to cancel out external influences, and one ground. Non-sync is sometimes associated to the tpe of input that it is usually connected to, but it really means nothing else than any non synchronised, i.e. non film source. The type of connection normally used for non-sync is called RCA connector and is unbalanced.  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 05-01-2003 08:58 AM                     Format -80 (Master Digital) is indeed a AES3 or S/PDIF input. You MUST have the Surround-EX decoder board in your CP-650 to take advantage of ANY of the Option I/O connector features, like the AES3 decoding. Presumming you have that card installed, then selecting format 80 will decode a consumer or professional AES bit stream into Dolby 5.1 or, if so programmed, decode a 2-channel PCM signal as a "Pro-Logic" signal. Unlike analog cables, digital audio cables carry two channels per cable so a single AES input has two channels on it. Any sound not syncronous to the film is consider a "non-sync" input. Steve  |  IP: Logged Adrian Steiner Film Handler Posts: 18 From: Baar, Switzerland Registered: Dec 2002 posted 05-01-2003 07:12 PM                     quote: I think you are confusing non-sync and symmetric. In English symmetric audio connections are called "balanced". D'oh! The correct expression in English is of course "balanced" and not "symmetric". I shouldn't post at midnight. I really ought to be familiar with balanced/unbalanced stuff, as I made an adapter cable so that the Hearing Impaired Output can be connected to the auditoriums old, balanced sound equipment. (And it works.) Shame on me for mixing it up! Now on topic: After a first read of the format 80 description all seemed clear: Input is a Dolby Digital signal (L, C, R, Ls, Rs, SW) or a PCM signal on a 110 ohm balanced AES/EBU line. But the note on the input wiring diagramm completely confused me: 2-channel AES/EBU digital output. 2-channel? The format 80 is about 5.1 channels. I think now, they want to point out that the AES/EBU line is balanced (110 ohms) (AKA AES3) and not unbalanced (coaxial 75 ohms cable) (AKA AES3id). If I got you right Steve, the configuration "DVD players S/PDIF into a S/PDIF to AES/EBU converter and this into the CP650 (with SurroundEX card)" should work. If anyone has any experience with this, please post if it finally worked or didn't. It's important to me to know that for sure, as S/PDIF to AES/EBU converters aren't cheap. Although I found simple converting circuits in the web I don't want to use them. They're mostly just impedance matching transformers with some resistors around it. I also won't build the more perfected circuit from an electronics magazine (Elektor). a) A CP650/EX card isn't cheap and b) the AES/EBU line won't be just 2 meters long. More likely 20 times longer. For reliability reasons I'd rather buy a professional one. Here are some I found by googleing around: S/PDIF -> AES/EBU: FP-DFC1 ~480$: http://www.markertek.com/MTStore/product.CFM?BaseItem=FP-DFC1 S/PDIF <-> AES/EBU: RU-UDC1 ~675$: http://www.markertek.com/MTStore/product.CFM?BaseItem=RU%2DUDC1 CO3 ~250$: http://www.markertek.com/MTStore/product.CFM?BaseItem=MM%2DCO3 Are there major differences in quality between the models (e.g. RU-UDC1 & CO3), or why is there such a big difference in price? Is it just the brand? Does anyone know of other/more converters? quote: Unlike analog cables, digital audio cables carry two channels per cable so a single AES input has two channels on it. I always assossiate "channels" with things like L, C, R, ... . Here you mean the signal wires in the cable, i.e. a balanced AES/EBU (AES3), don't you? Please write yes; or else my understanding of the whole topic is . Cheers, Adi P.S. Sorry for not posting so long. But a few days ago my enormous artwork of technichal poetry got lost as a URL was opend in the browserwindow I was writing the post. I was very depressed - like Marvin (from THHGTTG) [ 05-02-2003, 12:23 PM: Message edited by: Adrian Steiner ]  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 05-02-2003 11:34 PM                     Lets see if I can answer all of this... Dolby AC-3 rides on one channel of an "AES pair." That is, each AES cable has a pair of channels on it...period...that is its definition. So, the standard AES input of the CP-650 EX card has one-pair of AES inputs...normally written AES 1/2 (not one-half but one/two). The next pair would be written 3/4...etc up to the number of channels the system can handle). Invariably, Dolby's AC-3 bit stream rides on channel 1 of the first pair. If your source is so equipped, the CP-650 (when in master digital mode, format 80) will see the AC-3 bit stream and decode it as it was encoded (not necessarily 5.1). In fact, in the pro-world...5.1 would be described as 3/2L....which is read 3-front, 2-rear and Low-Frequency. Why not 5.1? Well the professional side of things will sometimes mix for just stereo for broadcast so a 2/0 mix may be on the AC-3 bitstream, just to site one example. Now since AES always comes in pairs (as described above), not all digital audio is Dolby AC-3 encoded. One may just mix a regular stereo mix and put left on channel 1 and right on channel 2. Again for broadcast this is a valid way of recording. One could also encode an Lt/Rt mix on the 2-channel digital audio. If you program your CP-650 to decode it, it will. There is an option on the front panel menu (not available on the software and you must be in "install" mode) where you can tell the CP-650 to take any stereo PCM signals and perform a pro-logic decode (strongly recommended for large screens, even if the source was not so encoded). Now to the S/PDIF...S/PDIF is primarily a consumer format. It is an unbalanced signal that travels on either a 75-Ohm coax cable or via an optical "Toslink" cable. It differs with AES-id in that it runs at a lower voltage and that officially S/PDIF and AES have different flags and headers. So merely going through a transformer to change the impedance from 110-Ohm to 75-Ohm (or vice-versa) does not change the encoding. Having said that...I have yet to find a situation where it didn't work and I haven't encountered any difference between the two. Companies like Radio Design Labs have genuine converters do more than just have transformer type baluns. What to do for the CP-650...nothing! Dolby already has the transformers on the EX board...you merely have to set the links on the board for the type of input you desire (AES3 or S/PDIF). So it is an either or situation, you can't have both. As a side note, AES3, AES-id, and S/PDIF all operate at different voltage levels....most inputs have the range to accommodate the extremes though they don't have to. For a good education on the world of S/PDIF and AES/EBU take a look at: http://www.rane.com/note149.html http://www.rane.com/pdf/note149.pdf (in pdf form) Lastly, yes you can hook your dvd player up to a CP-650 and it will play it just fine in Dolby Digial (AC-3) just like it was encoded. Steve  |  IP: Logged System Notices Forum Watchdog / Soup Nazi Posts: 215 Registered: Apr 2004 posted 03-02-2008 12:48 PM                 It has been 1765 days since the last post.  |  IP: Logged John Hawkinson Film God Posts: 2273 From: Cambridge, MA, USA Registered: Feb 2002 posted 03-02-2008 12:48 PM                     So, I find myself on a one-off with a CP650, and wanting to make it do pro-logic decode. In Format 80 with Pro-Logic enabled, we still get L/R output only. Toggling the state between Pro-Logic and Left/Right seems to have no effect. Any ideas/tips? This is running 2.2.5.3. --jhawk  |  IP: Logged Ron Funderburg Jedi Master Film Handler Posts: 814 From: Chickasha, Oklahoma, USA Registered: Nov 2007 posted 03-02-2008 03:21 PM                        Do you have stand alone Dobly Digital home unit? You can do the decoding in that and use pre-amp out to feed the amps direct and get your sound in the auditorium that way. You can hook up an alternate input direct from the Dobly Digital preamp to inputs on the processor as well and run it that way (but the Dolby Digital for the film would have to be turned off or you will have a significant loss of volume) and then feed out. I just am not sure what you are trying to do! There are several ways there to take advantage of the Dolby Digital on the DVD in the theater!  |  IP: Logged Brad Miller Administrator Posts: 17775 From: Plano, TX (36.2 miles NW of Rockwall) Registered: May 99 posted 03-02-2008 05:03 PM                     With the latest firmware you can assign NS2 to pro logic. Otherwise I think you just need to use NS1 and set it to pro logic decode. The digital inputs to my knowledge will not matrix out. It is expecting the channels to be discrete.  |  IP: Logged John Hawkinson Film God Posts: 2273 From: Cambridge, MA, USA Registered: Feb 2002 posted 03-02-2008 05:25 PM                     This wasn't really my show, and I didn't have much time to play, and it's over now. I think the problem is that DVD player was output AC3 and not PCM, and the CP650 can't decode AC3 at the same time as Pro-Logic. --jhawk  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 03-02-2008 05:45 PM                     John, If I understand your post correctly...you are feeding a S/PDIF stream to the 1/2 pair input on the CP650 Option I/O port. If this is correct, then selecting "PCM pro-logic" decode will do a pro-logic decode to PCM audio only. If it is a Dolby Digital encoded 2-channel or 2.0 as it sometimes goes by, then you will most likely get just a 2-channel output. The CP650 is not as slick as it should be, in that respect. What you should do on your DVD player is to force it to output Stereo only, not Dolby AC3 encoding...this will present a PCM audio that the CP650 will decode. This is a case where the home theatre A/V receiver beats the high-dollar Cinema processor. In fact, I often use a Prosumer grade A/V receiver/preamp for non-film audio and feed it into the 6-channel input on the CP650 or Mag/Aux on a Pana CSP1200. The A/V receiver/preamp also makes a dandy video switcher too and nowadays rips the audio off the HDMI outputs of modern DVD/Cable/Sattelite players. Steve  |  IP: Logged

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