Film-Tech Forum ARCHIVE: Are digital coax audio outputs universally compatible?

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Posted by Frank Angel (Member # 248) on 12-04-2008, 10:46 AM:

I am working with an older Onkyo TX-NR801 (circa 2004) A/V Receiver that has DTS and Dolby Digital decoding -- it has 2 digital inputs (coax). I want to connect a new Blu-Ray player to the Onkyo for sound only (HDMI output from the player will go directly to a HD video projector). The BR player's audio outputs are only PCM (coax) and a single analog L,R stereo pair.

Question is, are all coax PCM outputs/inputs created equal? Will the PCM outputs of the Blu-Ray contain all the formats that are present on the disk and will a older ONKYO (processor) coax input understand them? A lot can change between 2004 and 2008.

A good sign is that the formats that Onkyo claims it will processes are all the familiar audio variants: Dolby, Dolby Digital, Digital EX, Dolby Pro Logic, DTS, DTS-ES Discrete, DTS-ES Matrix, DTS Neo6 (I never heard of that one) and DTS 96/24. The only thing I don't see is the higher end, higher bit rate 7.1 systems, DTS-HD, Master Audio or Dolby TrueHD which in this particular setup they can live without them. The Onkyo also has two optical inputs but the player doesn't output optical.

In short, is a coax is a coax is a coax?

Posted by Joe Redifer (Member # 3) on 12-04-2008, 10:54 AM:

Plug it in and find out. You certainly don't need a special cable. Any random yellow composite video cable laying around on the floor that has been stepped on for years will do. You should be able to get normal DTS and Dolby Digital out of it, even if you select DTSHDMA or Dolby True HD from the movie menu screen. If not, then it is a crappy Blu-ray player.

You may also need to mess around in the Blu-ray player's setup menu to enable this.

Posted by Bobby Henderson (Member # 840) on 12-04-2008, 10:56 AM:

Coax is coax. Unless there is something wrong with the cable the digital output between the BD player and receiver should work. It's kind of strange that the player only has coaxial for the legacy digital audio output. Normally a BD player would feature optical output and then perhaps a coaxial output too.

DTS Neo 6 is a matrixed surround format somewhat similar in function to Dolby Pro Logic II.

The newer surround formats exclusive to Blu-ray (multichannel Linear PCM, Dolby TrueHD and DTS-HD) require HDMI connections. One can get by using an older receiver if it has multichannel analog inputs and the BD player has internal decoding and multichannel analog output.

Posted by Chris Slycord (Member # 4239) on 12-04-2008, 12:47 PM:

quote: Bobby Henderson
The newer surround formats exclusive to Blu-ray (multichannel Linear PCM, Dolby TrueHD and DTS-HD) require HDMI connections.

If the player does the decoding it could use analog connections for the sound.

Posted by Joe Redifer (Member # 3) on 12-04-2008, 12:57 PM:

I can't remember what I was watching or playing and my receiver usually defaults to Dolby Pro Logic IIx, but one time it was forced into DTS Neo 6 by the source. Connection is HDMI.

Posted by Bobby Henderson (Member # 840) on 12-04-2008, 05:10 PM:

Could it have been a gaming program? I was surprised after updating Super Stardust HD on my Playstation 3 the Dolby Digital audio was changed to DTS.

quote: Chris Slycord
If the player does the decoding it could use analog connections for the sound.

Didn't I say that in the sentence following the thing about HDMI?

Posted by Chris Slycord (Member # 4239) on 12-04-2008, 09:29 PM:

Yes. I fail.

Though it seemed confusing that you said both that the format itself "requires HDMI" then in a separate sentence say you can "get by with older equipment."

Though honestly when I read it the first time I only saw the sentence I quoted.

Posted by Frank Angel (Member # 248) on 12-05-2008, 04:41 AM:

quote: Joe Redifer
Plug it in and find out.

Most excellent, pragmatic solution. This I will do.

quote: Bobby Henderson
Normally a BD player would feature optical output and then perhaps a coaxial output too.

Yes, I found this strange that it only had coax and no optical. I think it must be a totally bare-bones unit. It's branded Sylvania, I think. I guess everyone is rushing to get into this market. I can't wait to see BR players made by the infamous Coby brand hanging in plastic formwraps in the local bodagas.

Posted by Bobby Henderson (Member # 840) on 12-05-2008, 10:50 AM:

That's probably not far off in the future. About a dozen Chinese companies are supposed to start making their own branded Blu-ray players sometime in 2009.

Posted by Joe Redifer (Member # 3) on 12-05-2008, 08:13 PM:

Chinese BD players? I simply can't imagine a Blu-ray player that can only play pirated VCDs.

Posted by Sam Graham (Member # 2889) on 12-05-2008, 10:45 PM:

quote: Film God Frank Angel
Yes, I found this strange that it only had coax and no optical. I think it must be a totally bare-bones unit. It's branded Sylvania, I think.

Yes, it's the Funai player (sold as Magnavox at Wal-Mart, Insignia at Best Buy). No optical output.

You may have to change a setting in the menu to send DTS out...I did on the Magnavox.

But considering Costco is selling it for $149 after instant rebate...

Posted by Steve Guttag (Member # 268) on 12-06-2008, 12:22 PM:

I'm seeing several lower-cost issued in the last 6-month players that are coax or HDMI for digital out...no optical.

Both Denon and Onkyo have near identically looking Blu-Ray players. Denon omits the optical output. It also appears that they are using the same metal work that, no doubt, others use.

Here is the Onkyo DVBD606:

Here is the Denon DVD1800BD:

Look similar?

Note too...there are devices out there that will make you what you need (optical or coax).

The lowest cost can be found at Joe's favorite cable outlet Monoprice

Coax to Optical converter

$11.16 each as of this writing...so break the bank. I have no idea how well this unit works but for $11.16, including wall-wart...how far wrong can you go?

For more trusted brands...there is Kramer and RDL

Steve

Posted by Demetris Thoupis (Member # 833) on 12-06-2008, 06:16 PM:

The best way to go and be sure about it is actually connect all 6 RCA's of your BluRay considering it has them (discrete channel outputs) to a multichannel input of your Onkyo (considering it has one). In this way you will get all audio formats since all the decoding is being done on the BluRay players' side.
Demetris

Posted by Joe Redifer (Member # 3) on 12-06-2008, 07:53 PM:

quote: Steve Guttag
Look similar?

Pretty close. One has an optical output and the other gets rid of it and puts a Windows® logo in its place. Maybe Denon thought that with Windows® being such a well-made invention that people support with lots of money because it is so good that some of that success would rub off on their bottom of the line Blu-Ray player as well.

Personally, I think I'd rather have the optical output. That is far more useful than Windows®.

Bottom line: Onkyo is better than Denon, even though it sounds waaaaay cheaper and "questionable", like a brand you'd find in the electronics section in the grocery store. I wouldn't trust anything called "Onkyo". But in this case, they win.

Posted by Austin Pelnar (Member # 5043) on 12-17-2008, 09:10 PM:

What better place to jump right on in. As far as I know the digital outputs are compatable so long as the proper decoder is at the other end for the format being sent down the line. The optical output is an exact duplication of the coax output, every player Ive seen the optical transmitter is a module 3 pins power ground and data. The data is usually just built out from the coax connection. It is very close to AES/EBU and should be ran thru a 75ohm cable in the case of a coax connection.
With that said a couple of tricks. In 2 channel the digital output is very close to good ol AES/EBU so close that most equipment cant tell the diffrence. In a pinch we used a minidisc player with optical digital output only, for an analog to AES converter, soldered a coax connector to data in pin of the optical transmitter to run to the end equipment. Need your coaxial digital signal to multiple pieces of equipment? Forget buying an expensive digital splitter just run it thru an el'cheapo analog video distribution amplifier.
A side note my bluray experiance is limited but as far as I know the output has to be selected in the player havnt seen all the formats coming down the line at once. DVD sometimes you can select via the disc player but most of the time you have to select vis disc menus so they can give you the correct ad for DTS or Dolby.