DVD analog sound over digital coax cable? (1 Viewer)

[Susana Anderton]

I've got a question.
I just got a new Denon 2802 receiver. I connected an Apex 600-a DVD player (I know, it's crappy) with an S-Video cable and a digital coax cable ONLY. I put an audio CD and an SVCD into it, and they both played out the receiver. How is the sound from these non-digital sources coming out the digital coax cable? Does the DVD player create the data stream on the fly, or do I not understand they way this stuff works?
Thanks

 

[Saurav]

Does the DVD player create the data stream on the fly, or do I not understand they way this stuff works?

When you use a regular CD player's analog outputs, it's the CD player that is converting the digital data on the CD into analong on-the-fly. These days, almost all CD players have coax and/or optical outputs, just like your DVD player. When you use the digital (coax/optical) output, the CD player does nothing, and it's the receiver that converts the digital data into analog sound. If you want to get more detailed, the receiver looks at the bitstream coming in on the digital cable and figures out that it's encoded in PCM, and not DD/DTS, so it processes it accordingly.
Records (vinyl) and cassette tapes are non-digital sources.

 

[Sean Conklin]

Welcome to the HTF Susana,
CD and SVCD are actually digital! Your player reads the info and sends it through the Digital Coax as 1's and 0's (bitstream) where it is then processed by your receiver's DAC (Digital Analog Converter) then amplified and sent to the speakers.
If you were to send the info through through regular analog jacks, your player would read AND process the information using it's own internal DAC then send the processed info to the receiver, bypassing the receiver's DAC.
So, if you use the Digital coax your receiver processes.
If you send it through the analog RCA jacks your DVD player processes.
See what I mean?
Ok I hope that helped!
**EDIT** It took me so long to type this, Saurav beat me to it! Someone always does!
------------------
Sean
"I was thinking of the immortal words of Socrates who said.......I drank what?"
[Edited last by Sean Conklin on November 03, 2001 at 06:50 PM]

 

[Susana Anderton]

Thanks for the info, guys.
2 more questions:
1. My DVD player setup has 2 digital options for Audio Output:
SPDIF/RAW
SPDIF/PCM
What's the difference? Which one should I use?
2. If I want to record from my DVD player to my S-Video VCR then would I also have to connect RCA audio cables from my DVD player? I guess I could try it, but I have to figure out how to do it first. Man this receiver is complicated!
Thanks
[Edited last by Susana Anderton on November 03, 2001 at 07:00 PM]

 

[PaulKH]

1. Good question

My HDTV box has a similar option so I'd like to know the answer too. My receiver doesn't seem to care which option I pick.
2. As far as I know, most (all?) DVDs have macrovision copy protection, so you won't be able to record anything off those DVDs to your S-Video VCR, sorry.
> Man this receiver is complicated!
Welcome to home theater. I'm convinced PCs and even computer networks are simpler than home theater at this point!

 

[Brett DiMichele]

Susana,
SPDIF is merly a cable connection refrence SPDIF or Sony-Phillips
Digital Interface as the name implies is a TosLink (Fiber) or
Digital Coaxial connection between components as oposed to
analog.
PCM and RAW are both digital music storage formats. PCM is
Pulse Width Control Modulation if I am not mistaken and RAW
is Raw Audio Wav Format, again if I am not mistaken.
I think most people would say use PCM over RAW if you can
select between the 2.
If any of my info is incorrect someone will step in and
correct me I am sure
And yes it does get confusing!
------------------

Brett DiMichele
My Home Theater Site!
[email protected]

 

[Susana Anderton]

>> 2. As far as I know, most (all?) DVDs have macrovision copy protection, so you won't be able to record anything off those DVDs to your S-Video VCR, sorry.

 

[Michael Reuben]

Do think the receiver would convert it to analog and send it to the tape

Probably, but there's an additional consideration. If you're recording a DD 5.1 soundtrack to tape, you'll need to downmix it to two channels. Most receivers can't do this, but every DVD player can. So you're probably better off with an analog connection direct from the player to the VCR.
M.

 

[Karim Nogas]

When you use a regular CD player's analog outputs, it's the CD player that is converting the digital data on the CD into analong on-the-fly. These days, almost all CD players have coax and/or optical outputs, just like your DVD player. When you use the digital (coax/optical) output, the CD player does nothing, and it's the receiver that converts the digital data into analog sound.

I'm confused. Since CD is a digital format, why does the sound get converted to analog if everything is hooked up with a digital cable?
I'm using my DVD player to play CD, hooked up to a Denon via coax. The "Digital" LED is lit up all the time, so I just assumed there is no conversion going on.
If there is always an analog conversion along the path, wouldn't it be better to connect via RCA to eliminate converting the signal (i.e., better sound)?
------------------
You don't need a centre channel.

 

[Saurav]

I'm using my DVD player to play CD, hooked up to a Denon via coax. The "Digital" LED is lit up all the time, so I just assumed there is no conversion going on.

You assumed the right thing.
Please re-read what I said, and I think your confusion will be resolved.

 

[Karim Nogas]

Sorry Saurav, my question wasn't clear.
What I'm confused about is why there is any converstion at all if you are using a digital source and only digital connections, regardless of whether it takes place at the CD player or receiver.
------------------
You don't need a centre channel.
[Edited last by Karim Nogas on November 04, 2001 at 06:13 PM]

 

[Steve Daniels]

Karim,
I can't speak for Saurav, but I think I can answer your question.
The reason that the signal needs to be converted from digital to analog is because we can't hear in zeros and ones.
Inside the receiver, the digital signal is converted to an analog one at the (end of the) pre-amp stage. This analog signal is sent to the amplifier section where it is amplified and sent out through the speaker outputs.

 

[Brett DiMichele]

if you sent a "digital" signal through an amplifier and out
to the speakers all you would hear would be clicks or thuds.
The digital information has to be converted back to analog
and then amplified and sent to the speaker so that it can
reproduce the sound. Binary code played through a speaker
would sound like morse code, not music
------------------

Brett DiMichele
My Home Theater Site!
[email protected]

 

[Saurav]

I guess that answers your question?
Sound is analog. It is recorded as an analog electrical signal, converted to digital and stored on the CD. When you play a CD, the digital information (i.e., 1s and 0s) is read from the CD, and has to be converted back to the original analog signal that was initially recorded. This analog signal is now sent to your speakers, which produce the sound.
If you'd like to know how the process works in more detail, you could try dearching google.com for "digital audio basics". I've seen some sites on the web which do a pretty good job of explaining the various steps involved - sampling, quantization, encoding, regeneration, and so on.

 

[Vin]

My question refers to the fact that the audio from the DVD to the receiver is digital and I want to record it onto a tape. Do think the receiver would convert it to analog and send it to the tape, or would I have to have analog RCA audio cables connected from the DVD also?

Susana, my guess would be that you don't need to use the left and right stereo cables, here's why: my satellite receiver is connected to my Kenwood VR-507 A/V receiver with a digital (optical) connection only. Most satellite programming is still only analog, yet the audio signal is passed from the satellite receiver to my A/V receiver via the optical cable where it is then processed and played back in DPL, DPL2, or Circle Surround depending on which format I've chosen.
When a digital signal is being broadcast, my A/V receiver senses it and automatically switches to Dolby Digital as indicated by a red light.....unfortunately there's very little 5.1 programming being offered. Most of the DD programming is only 2.0 channels so I'll usually go into my satellite receiver's audio menu and manually choose analog (I prefer DPL2 or Circle Surround over DD 2.0).
I don't know for sure if the converted audio signal (from digital to analog) could then be passed to your VCR via the A/V receiver's analog output (I currently have a set of analog cables going directly from the satellite receiver to my VCR for recording purposes) but I don't see why not.
Hope this helps.

 

[Karim Nogas]

Thanks for the replies.
Sorry for the dumb question.
------------------
You don't need a centre channel.