Film-Tech Forum ARCHIVE: connecting dvd to DA20 + CP65

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Posted by Bhaskar Dhungana (Member # 1283) on 03-30-2003, 11:59 AM:

How do I connect a DVD to DA20 + CP65 setup in order to get the proper effect of Dolby Digital from DVD player?

Posted by Joe Redifer (Member # 3) on 03-30-2003, 12:09 PM:

Wow. I'm really confused. Do I move this to "The Afterlife" forum for home theater or not? I'll leave it for one of the other moderators I guess, as I am incapable of such a decision. Plus it talks about the CP65.

Anyway you cannot use a DA20 to decode the Dolby Digital from a DVD player. The DA20 actually transforms video into the digital code. And even then there are the issues of bitrates. Film runs at a constant bitrate in 5.1 all the time always. DVDs are all over the map. Some streams have 2.0 or 3.1 channel sound, etc that the DA20 cannot handle. Dolby has a new device shown at ShoWest this year which can handle every type of bitstream you throw at it, though.

Posted by Scott Norwood (Member # 30) on 03-30-2003, 12:18 PM:

Get a DVD player with a built-in Dolby decoder. This will have discrete outputs for each channel. Then, just connect each output to the respective input on the CP65 mag/aux input. You don't need the DA20 at all for this, though you will probably need/want a setup disk and SPL meter to set the levels on each channel.

Posted by Bhaskar Dhungana (Member # 1283) on 03-30-2003, 12:23 PM:

In that case what does it mean when a dvd has Dolby Digital 5.1 at the back?

By the way, this is just a experiment that I am trying with a DVD player and a DLP projector.

I believe somebody else was trying something of this sort with a CP55.

Posted by Michael Schaffer (Member # 1204) on 03-30-2003, 02:16 PM:

Bhaskar, report to my post at the top of Film-Yak!!!!

It says 5.1 Dolby Digital on the back of the DVD, but the format on DVD is a bit different from the one used for films. The bitrate is actually higher on the DVDs than in the cinema!
That is why the DA20 wouldn`t be able to decode it.

Plus, as Joe already said, the Dolby Digital code is read from the film with a mini TV camera and sent to the DA20 not as digital code, but as an analogue video signal of the image of the data blocks. The DA20 then converts the analogue video signal into a digital video signal and scans it for synchronisation and sound data.

So you can`t input the digital data from the DVD player. Sorry!
But as Scott said, you can easily connect the analogue outputs of the DVD player to the CP. You can also route it through the DA20 if you like. Then you can use the same input for both devices.

Posted by Bobby Henderson (Member # 840) on 03-30-2003, 03:13 PM:

Roger Dressler of Dolby Labs told me the AC3 bitstreams on film differ from that of the home theater version mainly over copy protection software included in the various bitstreams. You would not be able to feed digital data from a 35mm film print and have a home theater Dolby Digital decoder process it. And a DA20 will not decode a DVD's DD bitstream either.

Bitrates aren't much of an issue since all Dolby Digital decoders can handle up to 640kb/s of data. But the film version makes the DA20 process about 550kb/s off the film print, with 320kb/s being the actual audio track and the remaining data used for error correction purposes. That's one likely reason why 35mm film has a lower DD bitrate than DVD or D-VHS (D-VHS has the highest DD bitrate, using 576kb/s instead of the 384kb/s and 448kb/s rates commonly found on DVD).

Baskar, to find out if your DVD player has a built-in DD decoder with full 5.1 output check the back of your player. Such players will feature analog line out jacks for all six channels and have them labeled as such. If your player has that, just follow the instructions Scott gave on hooking it up to the cinema processor auxillary input.

Most DVD players do not feature full DD decoding and 5.1 analog output of the signal. Such models used to be common when cheaper "Dolby Digital ready" Pro-Logic receivers were available (such models have largely disappeared now).

Your best bet for buying a new DVD player with 5.1 analog output is choosing a DVD Audio machine, or a unit that can play both DVD Audio and Super Audio CD formats. The copy protection fanatics have largely prevented such players from being able to digitally output high rez audio streams to outboard decoders and D/A converters for true audiophile quality sound. You're pretty much stuck with having to hook up such a player using 5.1 analog leads. As such, nearly all of these kinds of players feature internal decoding and 5.1 analog output of Dolby Digital, DTS and various other higher quality audio formats.

Posted by Michael Schaffer (Member # 1204) on 03-30-2003, 03:31 PM:

quote:
The copy protection fanatics have largely prevented such players from being able to digitally output high rez audio streams to outboard decoders and D/A converters for true audiophile quality sound.

But they can still output the Dolby or dts data via the digital output?
If you hook up such a player to a receiver, most of which convert external alogue sources at 44,1 kHz for internal processing, then you would lose the high resolution of the SACD or DVD Audio. So what would be the point in having the new format?

Posted by Bobby Henderson (Member # 840) on 03-30-2003, 11:44 PM:

Yes, DVD-A capable DVD players do have standard optical and coaxial digital outputs for sending DTS, Dolby Digital and lower bandwidth LPCM data to a receiver.

The Merdian Lossless Packing format for DVD-A and the Direct Stream Digital format of Super Audio CD are both incompatible with standard digital outputs. High bandwidth digital connnections like Firewire would be required. So far that has largely been prevented by groups like the RIAA. There might be a model or two on the market by Meridian equipped with Firewire Input/Output, but I don't know if anything has been done to actually allow such I/O to be legally enabled.

For sake of convenience, most DVD-A players feature the full internal decoding and analog 5.1 output of DD and DTS so home users can hook up the 5.1 analog leads to one single auxiallary input without having to wire the DVD player effectively through two source banks on a receiver.

Posted by Stephen Furley (Member # 1277) on 03-31-2003, 03:53 AM:

The Dolby DMA8 Digital Media Adapter has a 'Consumer Dolby Digital' input. DVD is one of the uses mentioned in the spec sheet. This unit also handles PCM, but obviously would not play dts tracks on DVDs. More surprisingly, it doesn't seem to be capable of decoding MPEG tracks. MPEG audio on DVD is not very common, but it does exist, most are only 2 channel, but I've got a couple of multi channel ones. I've no idea what this thing costs, but I doubt that it is cheap.

For occasional use, feeding the bitstream from the DVD player into a domestic AV amplifier/receiver, and taking a 6 channel analogue from that into the mag/aux input input on the CP-65 might be an answer, Im not sure if any signal level or impedance matching would be needed.

The DA-20 is no use for DVD.

Posted by Michael Schaffer (Member # 1204) on 03-31-2003, 07:28 AM:

quote:
so home users can hook up the 5.1 analog leads to one single auxiallary input without having to wire the DVD player effectively through two source banks on a receiver.

But if the receiver`s internal processing is digital and the incoming signals are converted to 44,1kHz? [Confused]

Posted by Gordon McLeod (Member # 33) on 03-31-2003, 11:23 AM:

Creative Labs make the an excellent outboard DD decoder that accepts the SPDIF from a DVD player

Posted by Bobby Henderson (Member # 840) on 03-31-2003, 05:32 PM:

quote:
But if the receiver`s internal processing is digital and the incoming signals are converted to 44,1kHz?

That is a concern with DVD-A and SACD players. If your receiver or surround controller takes the incoming 5.1 analog audio and converts it into digital data for further processing there is a big concern about audio quality being harmed.

With every step of analog-digital and digital-analog conversion, you effectively get a generational loss on audio quality. The high rez MLP and DSD formats of DVD-A and SACD are billed as audiophile master-quality storage formats. But if playback is compromised by extra A/D and D/A steps before the sound hits the amplifiers then it kind of makes using higher quality 5.1 formats instead of lossy Dolby Digital and DTS a moot point.

Another added disadvantage with DVD-A players is a general lack of bass management. Apparantly, most manufacturers believe anyone who buys a DVD-A player will have very expensive full range speakers capable of producing a full 20Hz to 20kHz flat tone at full reference volume (very few speaker systems can honestly do that). So if your receiver directs the 5.1 analog audio directly to the amplification stage (which is what you want) you are getting a signal with no bass management, unless your receiver will handle such duties in the analog realm.

Posted by Michael Schaffer (Member # 1204) on 03-31-2003, 10:36 PM:

I don`t follow the home entertainment market, are there receivers at all which are SACD/DVD-Audio ready with higher conversion rates than 44,1 kHz? If I understand your first post correctly, then those players can not output high sampling rate audio digitally, or will not do it for copy pretection reasons or whatever. So one would have to go with a 6-channel analogue receiver to preserve the high audio quality. I understand that almost all multichanner receivers on the market have digital internal procession.

Posted by Bhaskar Dhungana (Member # 1283) on 03-31-2003, 10:39 PM:

Couple of more questions:

1. What is it when a DVD player says it has 192kHz Upsampling ?

2. What if I take each of the of the channels from Multi-channel Audio Out directly to my JBL MPA and MPX amplifiers? Would that give me digital sound? How good would that be to the film sound?

Posted by Michael Schaffer (Member # 1204) on 03-31-2003, 10:42 PM:

Sorry, no more questions until you report to my post at the top of the Film-Yak forum [Wink]

Posted by Bobby Henderson (Member # 840) on 04-01-2003, 12:18 AM:

To answer about receiver sample rates, all should handle normal 44.1kHz rates off of music CD and 48kHz off DVD. But the real question comes in when rates like 88.2kHz, 96kHz and 192kHz come into play.

I've seen a lot of gobbledygook in various manuals where they claim the receiver will handle such rates. Same for regular non-DVD-A compliant DVD players. But without the digital interconnect to (such as Firewire) that built in capability is about as useful as tits on a bull.

As an observation, most standard DVD players will downsample any high-rez audio track. For example, the "Seven" Platinum Edition DVD has a 2.0 channel 96kHz LPCM version of the opening title credit (along with DD-EX and DTS-ES 6.1). The bitrate of that track is 4096kb/s. My DVD players and any others I've tried downsample it to 48kHz.

I think you have to really get into the fine print about whether or not a receiver will allow a 5.1 analog input signal to stay analog and go straight to the amps. And even if that is preserved, you're still dealing with "mid-fi" quality digital/analog converters in most DVD-A players themselves.

Still, in principal, I think it is a good idea for the music industry to try to pursue a higher quality audio standard --even if it means for now the only place where that higher quality is displayed is on the actual master.

And to get back on topic, a DVD-A player is likely your best bet to hook up to a theatrical cinema processor because of all the decoded formats you get out of that 5.1 analog output.

Posted by Michael Schaffer (Member # 1204) on 04-01-2003, 12:24 AM:

What about the typical sampling rate at which incoming analogue data are converted by the receiver for internal processing?

Posted by Michael Schaffer (Member # 1204) on 04-01-2003, 02:42 PM:

OK, Bhaskar, I see you have reported to the thread as THE FIRST ASIAN MEMBER! Well, William Bunch is in Japan, but he is from the US (but I put him on the list because it is about geographical distribution).

1. Basically upsampling means that the player reads data recorded at lower sampling rates than 192 kHz (such as 44,1/48/96) and tries to fill in the "blank" spots to effectively achieve 192 kHz by analysing the signal and trying to "reconstruct" those samples.
2. You would bypass the CP`s equaliser and that would likely compromise the sound quality in the auditorium. Plus, it would be much easier to switch formats from film to DVD by simply pushing a button rather than rewiring the amps. Then you could make direct comparisons of the sound quality of film and DVD sources.

Posted by Bobby Henderson (Member # 840) on 04-01-2003, 05:18 PM:

An incoming signal of 5.1 analog audio has no sample rate. It is just an analog signal not containing digital samples. Now the quality of that analog signal will depend on what the D/A converter the DVD player did to it before it was converted into the analog domain.

My understanding is the D/A converters in a DVD-A or SACD player will do the conversion at the native sample rate of the track being played back and not downsample it to something like 44.1kHz. MLP material on DVD-A would normally be 5.1 with 96,000 24-bit samples per second, or 2.0 channel 24-bit with 192,000 samples per second. SACD's DSD format is a 1-bit delta modulation process using 2.8 million samples per second (someone please correct me if that number is wrong).

If the DVD-A or SACD player downsampled the signal before converting it to analog for output/playback, then what would even be the point on buying such a player, right?

Posted by Michael Schaffer (Member # 1204) on 04-01-2003, 05:52 PM:

quote:
An incoming signal of 5.1 analog audio has no sample rate. It is just an analog signal not containing digital samples.

Oh, really [Wink]

?

Maybe I didn`t make quite clear what I meant. I meant if you have a high class SACD or DVD-A player which would output the analogue using a high quality D/A converter without downsampling (just like you described). But then you would still need to amplify the signals, so you plug it into a 6-channel receiver and THAT would convert the incoming analogue signals at 44,1 kHz for internal digital processing. Or are there receivers out there now which can sample incoming analogue at 96 or even 192 kHz?

Posted by Bobby Henderson (Member # 840) on 04-02-2003, 12:10 AM:

A receiver might be able to apply any number of sample rates to an incoming analog signal, but that would still be bad. The way DVD-A and MLP is set up, there should be absolutely no digital treatment to the signal after it leaves the player.

The process of digital-to-analog and analog-to-digital conversion is not perfect. You get a generational loss of quality. Going through one D/A stage is a necessary evil for amplification. Putting the signal though D/A, A/D and D/A again is terrible.

Most DVD-A and SACD players have decent, but not high end, D/A converters. So that's one problem. You're not going to get the full 24-bits worth of oomph out of that MLP track. Current electronics are just not capable of it. Limits in the D/A unit, electrical resistance and interference and other factors trim away audio quality. That's the reason I argue for a Firewire digital output. Those who can at least afford high end D/A units in a top quality surround controller (and then use mono-block amps) would be able to use the Firewire connection to preserve more audio quality upon playback. That would be closer to an "audiophile" solution.

If a receiver forces any DVD-A or SACD signal to go from analog back into digital and then back to analog, it would be no more than a "mid-fi" setup. The end user would be better off watching music videos on standard DVD and probably get audio just as good from DD and DTS.

Posted by Steve Guttag (Member # 268) on 05-02-2003, 11:46 PM:

To answer the original question (how to hook a dvd player to a DA20 +CP-65). The answer is easy, though a bit pricey for some. As has been noted, the DA-20 is strictly a film decoder. It can not and will not deal with pro or consumer AC-3...sorry.

Dolby does make the DMA-8 though (Digital Media Adapter) that will let just about any Cinema processor, including the CP-65 have a means for dealing with pro and consumer AC-3 plus a whole lot more. It handles Dolby-E (broadcast) and is an 8-channel D/A converter plust can handle several different inputs with automatic switching.

http://www.dolby.com/products/DMA8/

http://www.dolby.com/products/DMA8/mp_br_0112_DMA8.pdf (brochure in pdf form).

The unit lists for $6,000 so it isn't the inexpensive way out but it will let the typical cinema handle the typical pro/broadcast audio.

Steve

Posted by Michael Schaffer (Member # 1204) on 05-03-2003, 08:17 AM:

But why? If there is already a good DVD player with good analogue outputs at hand, why buy the DMA8?

Posted by Mark Gulbrandsen (Member # 72) on 05-03-2003, 09:10 AM:

"Wow. I'm really confused. Do I move this to "The Afterlife" forum for home theater or not?"
_________________________________________________________________
There are many of us that wish you'd move to the afterlife! [Razz]

Mark

Posted by Steve Guttag (Member # 268) on 05-04-2003, 11:02 AM:

The DMA-8 is more than just a DVD decoder....and most DVD players do not have 5.1 analog outputs.

As I stated before, the DMA-8 will handle consumer and Professional AC-3, PCM (up to 8-channels), Dolby-E (up to 8-channels) and allow one to use a common "digital" input on their analog processor, like the CP-65.

It has 4 AES-pairs on a DB25 connector, analog 5.1 input, TOSLINK, Coax BNC input and a Coax RCA input. These inputs may be prioritized so that will will select the highest priority valid digital data. In addition to the front panel buttons (digital media and Film), you can control the unit via RS-232 so if you have a Crestron or AMX type controller one can integrate the film system and video system better.

Again, the DMA-8 is not and will not be for every theatre...it all depends on your needs. In my opinion, the DMA-8 is overpriced and is severely lacking information/control on its front panel (there are just the two buttons with associated LEDs...no channel indicators, no mode indicators). If one has a computer, then you can see what it is doing and control it better.

Now if you theatre plans to run professional video shows (festivals and rentals) then the DMA-8 can offer some good value. That digibeta tape could have PCM, AC-3 or Dolby-E on it (and you won't know in advance...trust me)...the DMA-8 deals with it all and provides the audio out in analog form at the typical Dolby buss level of 300mV without having to rewire your system.

Steve

Posted by System Notices (Member # 2357) on 03-11-2005, 02:35 PM:

It has been 677 days since the last post.

Posted by Dominic Espinosa (Member # 2122) on 03-11-2005, 02:35 PM:

The question I have after looking this over is this:
If you've got a player with 6chan out, what processor is best suited to take that input into it's aux for the best audio quality?

Also, what options do those of us with optical out's on the DVD player have? [EDIT: Answered my own question looking at specs on the DMA8 ].
Though, that does bring up another question, is the DMA8 the only option for those of us with an S/PDIF output from the DVD player who want to use a CP65 or similar processor?
I'd like to move all of my audio processing needs into a single unit, say a CP65 so that I can play DVD's, Games, and 35mm (when I can afford to build a screening room) out of one box.

Posted by Richard May (Member # 2627) on 03-12-2005, 07:17 AM:

We have a CP65 that I made a patch panel for. The panel goes to the digital inputs on back of the processor. We hook up DVD players (6 Channel), VCR's, and Beta decks. It works fine. The only problem with DVD is the sub level. Can't seem to get it quite loud enough.

Posted by Dominic Espinosa (Member # 2122) on 03-12-2005, 12:24 PM:

That's interesting...Is there a trick to making the patch panel?
I never really got into anything more than swapping out boards in the CP650's at my old job.

Posted by Richard May (Member # 2627) on 03-12-2005, 01:30 PM:

I used a single rack space blank panel and drilled 6 holes for chassis mount female 1/4" phone plugs. We use it for any line level signal other than film, including a microphone. It's wired directly into the digital in inputs on back of the CP65.

Posted by John Hawkinson (Member # 1135) on 03-12-2005, 10:54 PM:

Consider using a professional patchbay like the Behringer Ultrapatch PX1000. It's 1U high and gives you 24 channels of 1/4" insert/replace (or 48 straight-through, with other configurations...).

At $40, its almost cheaper than your time for building a panel. And the insert/replace (aka add/drop) features are really handy when you want them.

--jhawk

Posted by Richard May (Member # 2627) on 03-13-2005, 08:21 AM:

It only cost me about 6 bucks my way. Either way you do it, you still have to wire it into the rack.

Posted by Dominic Espinosa (Member # 2122) on 03-14-2005, 03:38 PM:

I think I mis-stated my question.
What I meant is, how would one go about converting that optical out on the DVD player into a 6ch source for the processor's aux input, or is it even possible without the use of another processor?

Posted by Brad Miller (Member # 2) on 03-14-2005, 04:16 PM:

Not possible Dominique. The CP650 can be equipped to decode the AC3 track, but no other processor out there (to my knowledge) can do it. You would have to have an outboard AC3 decoder converting the optical to 6 seperate channels of audio before inputting that signal into the CP65.

Posted by Dominic Espinosa (Member # 2122) on 03-14-2005, 04:34 PM:

Well, that stinks.
So I suppose the only way to do it is with either a DVD player which decodes the AC3 stream onto 6 analog outs, such as the Toshiba SD-4800.
The question now is, because of the shoddy bass management would it be better to derive the LFE data from the surrounds like in SR if you're just watching movies?

It would be nice if you could just pipe the AC3 stream from the dvd, out the serial port on your computer, and into the processor, all digital...dwah!

But hey, now we can add Brad to the list of people who've called me by a girls name [Roll Eyes]

Speaking of Brad, what do you use to power your DLP in your screening room? I've heard rumors that you've got one [Wink]

[ 03-15-2005, 03:44 AM: Message edited by: Dominic Espinosa ]