5.1 vs digital out

Discussion in 'Audio Hardware' started by sgraham, Nov 13, 2002.

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  1. sgraham

    sgraham New Member Thread Starter

    Location:
    Michigan
    A friend asks, and I don't know the answer: If you have a DVD player with a digital output, and a 5.1 receiver with a digital input, do you get discrete 5.1 if you plug the digital out into the digital in? Or is it crippled so you can only get Dolby Surround or some such nonsense?

    I know there are some limitations on what you can get from this type of digital connection, for reasons of, ahem, "copy protection", but I'm not sure what they are.
     
  2. Richard Feirstein

    Richard Feirstein New Member

    Location:
    Albany, NY
    If you play a DVD disk containing 5.1 material, and have the DVD player setup to output 5.1 from the digital output, your receiver will be able to decode the discrete 5.1 information if it is setup to do so. SACD and DVD-A will require hardware with HDMI interconnects, still a year away.

    Richard.
     
  3. NoTinEar

    NoTinEar Suspended

    This isn't a personal attack on what you said, but I will believe that year when i see it. I mean in a mass market saturation level of digital transfer for sacd or dvd-a. The two camps are so hard headed and non cooperative I will wait and see what happens and enjoy the analog outputs for now.
     
  4. NoTinEar

    NoTinEar Suspended

    As far as this question is concerned Richard is absolutely correct. I thought I would give a little more detail. The dvd player may or may not need to be set up, that is you have to go into its menu system and choose the correct settings. Different players will have different options. For instance if you want to hear Dolby Digital, which by the way comes in 1.0, 2.0, 3.0, 4.0, 5.0, and all of those with a .1 also, you have to tell the dvd player to output a Dolby Digital signal. The dvd player may or may not default to this option. If you don't choose it and it doesn't default to this option then it most likely will covert the Dolby Digital to a PCM track.

    Now beyond that the actual dvd's themselves may have more then one Dolby digital track as an option. Usually it will have a 2.0 and a 5.1 soundtrack. Now some dvd players automatically choose the 5.1 track and some don't. If there is any doubt then one has to go into into the "dvd menu" and choose the 5.1 track.

    Now the above has nothing to do with DTS, which also usually has to be turned on in the dvd player to output via the digital output. Again as with the Dolby Digital software it is wholly possible the DTS might be 2.0, 4.0, etc. and not a 5.1 track. And again it may have more then one DTS track and if you want 5.1 track you may have to choose it in the "dvd menu".

    Now finally you do have to tell the receiver to go into surround sound mode. That usually is marked "pro-logic" or "Dolby digital" or "DTS". You may have to do this every time you watch a different dvd, depending on if your receiver stays in the same surround mode. Most of them do. If it does stay in the same mode however, that means when your listening in 2 channel or some other surround sound mode, its going to process the 5.1 Dolby digital into that surround mode, instead of the actual Dolby digital mode.

    So at any rate, you can see there are many variables and actually more then that depending on the receiver. That should answer the basic questions, sorry if it was too much info...
     
  5. Steve Hoffman

    Steve Hoffman Your host Your Host

    Test. Guess it's working again...
     
  6. Richard Feirstein

    Richard Feirstein New Member

    Location:
    Albany, NY
    I don't know when the HDMI interconnect standard will be applied to hardware; for a final standard we are still holding our breath. But digital video output from a DVD player merely requires a properly configured DVI output, and that standard is in place.

    Richard.
     
  7. JoelDF

    JoelDF Senior Member

    Location:
    Prairieville, LA
    Richard is correct, as NoTinEar noted, about Dolby Digital from DVD.

    5.1 Dolby Digital has been part of the DVD standard since it's inception - although DTS tried to get in there, the DVD forum simply left room for them as an option.

    Dolby Digital (formerly known as Dolby Surround Digital AC-3), has always had a minimum of 1 and maximum of 6 (or 5.1 if you like) discrete channels encoded into a single digital stream. It was first introduced into the home video market in 1995 with the Paramount release of Clear and Present Danger on Laserdisc. The AC-3 was squeezed into the laserdisc’s right analog audio channel as an RF modulated signal that had to be demodulated before being decoded back out to 6 digital channels, amplified, and sent to the 5 full range speakers and 1 subwoofer.

    As I said, Dolby Digital is encoded as a single digital stream. It is stored on whatever medium it’s on as such. With DVD, it no longer needed to be folded into an RF signal – it can now be left as its native encoded digital stream. It doesn’t matter if the DD signal is decoded in the player itself or sent via the digital out (coaxial or optical) to an external receiver or decoder, you will eventually end up with 5.1 discrete channels to amplify – it has to be decoded somewhere.

    The only time you get DD mixed-down to Dolby Surround is if you are playing a DVD that is set for Dolby Digital but only have the analog L/R outputs from the player hooked up to your receiver. And, as per Dolby specs for such a mix-down, the .1 channel is tossed and not included in the Dolby Surround compatible output (although some players have been known to ignore that part of the spec and will fold the LFE – low frequency effects - channel into the main L/R channels for analog output). That is why it’s always suggested that if you only have analog hooked up from the DVD player, and you have the option to choose the Dolby Surround soundtrack over Dolby Digital – do so, because the DS track will always have the proper bass mixed in over the DD mixed-down DS version.

    DTS and straight PCM comes from the same digital out connection.

    BTW, as already noted, for most players, DTS has to be turned on from the DVD players setup menu (I know Pioneers have to be done that way). DD is usually already on my default because they assume that if you are going to hook up the digital outputs, then you must have at least a DD receiver to hook it up to - since that is the DVD standard.

    Joel
     
  8. NoTinEar

    NoTinEar Suspended

    That is true as far as the video is concerned. The earlier post i responded to made no mention of a hi-rez video standard. I was merely commenting on the digital hi-rez connection. Again as I stated, I will believe it when i see it.
     
  9. krabapple

    krabapple New Member

    Location:
    Washington DC


    Yes, assuming the receiver with the digital in has a 5.1 decoder, which most do
    (look for the 'Dolby Digital' logo on the front).

    Not sure what you mean. Old-fashioned Pro Logic (and new fashioned Pro Logic II) are often switchable options on new receivers.
     
  10. sgraham

    sgraham New Member Thread Starter

    Location:
    Michigan
    Re: Re: 5.1 vs digital out

    What I meant was do you get discrete 5.1 or do you only get a matrixed decode?
     
  11. krabapple

    krabapple New Member

    Location:
    Washington DC
    Re: Re: Re: 5.1 vs digital out

    Discrete -- but this is called "Dolby Digital Surround' too.
     
  12. JoelDF

    JoelDF Senior Member

    Location:
    Prairieville, LA
    As I stated in my last post - digital out is the only way to get 6 discrete channels (5.1). Unless the player has a built-in decoder (usually not suggested though, because of quality issues).

    You only get matrixed surround out of the analog L/R outputs.

    And, you only get the mixed-down (or down-converted as some call it) 2 channel surround from the original 5.1 (with the .1 tossed out) when you play a selected DD 5.1 track through the analog L/R outputs from a DVD player.

    What we've all been trying to say is - it's not "5.1 vs. digital out" - digital out is the way to get 5.1. But, you need a decoder to extract the 6 channels from the digital stream. Whether it's from the player itself or from an external receiver or dedicated decoder.

    Joel
     
  13. krabapple

    krabapple New Member

    Location:
    Washington DC
    Re: Re: 5.1 vs digital out



    To be clear: If you use the player's decoder, you get matrixed surround out of the analog 6-channel outputs. All your receiver has to do is pass it to the speakers.

    Alternately,you get undecoded matrixed surround out of the digital out, and let the receiver decode it.

    I'm not aware of quality issues with DVD-player built-in surround decoders, versus those in HT receivers or preamps/processors. AFAIC it's more an issue of what sort of control you have over the surround output, in your receiver versus your player (e.g., amount of fiddling you can do with bass management and time delay) , and what connections you have to make (digital is one cable, analog is 6).
     
  14. sgraham

    sgraham New Member Thread Starter

    Location:
    Michigan
    Re: Re: Re: Re: 5.1 vs digital out

    Sorry, I should have said "Pro Logic" or something.
     
  15. sgraham

    sgraham New Member Thread Starter

    Location:
    Michigan
    Re: Re: 5.1 vs digital out

    My SACD player is also a DVD (Video) player with six channels of analog out. What quality issues? Do you mean to say that a surround receiver will have superior audio quality?
     
  16. sgraham

    sgraham New Member Thread Starter

    Location:
    Michigan
    Re: Re: Re: 5.1 vs digital out

    Sorry, we seem to be getting murkier.

    Seems to me you get *discrete* surround out of the analog 6-channel outputs, unless you are playing from a Dolby Pro Logic type soundtrack.
     
  17. JoelDF

    JoelDF Senior Member

    Location:
    Prairieville, LA
    Re: Re: Re: 5.1 vs digital out

    krabapple may be right about quality not really being an issue - anymore.

    It was for some of those early buget DVD video players with built-in decoders and had 6 channel analog outputs. But then you would need an amplifier that has 6 channel inputs. Many do, of course. All those players still had a digital out, though (or at least should have).

    I was also sticking with the video player realm, not audio SACD players.

    Joel
     
  18. krabapple

    krabapple New Member

    Location:
    Washington DC
    Re: Re: Re: Re: 5.1 vs digital out

    Your'e right, I had a complete brain freeze on that one. Sorry!

    Replace 'matrixed' with 'discrete' in that entire post, and it comes out right.
     
  19. sgraham

    sgraham New Member Thread Starter

    Location:
    Michigan
    Not to worry. My brain freeze on Sunday blasted a lot of people out of their church seats....
     
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