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Digital Output or Analogue Output for 5.1 playback?

Discussion in 'Playback Devices' started by Jeffrey Wiffen, Oct 9, 2003.

  1. Jeffrey Wiffen

    Jeffrey Wiffen Stunt Coordinator

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    For a couple years now I have been feeding a digital signal from my Toshiba SD4800 (DolbyD 5.1 decoder equipped) to my NADT760 (DolbyD 5.1 and DTS 5.1 decoder equipped) with a decent WireWorld digital-coax cable.

    I recently decided to buy six interconnects so I could utilize the DVD players DVD-Audio decoder.

    The other night I decided to try out listening to a DolbyD 5.1 movie soundtrack via the DVD players six analogue outputs and not the digital-caox output, opting to use the DVD player's DolbyD 5.1 decoder instead of the NAD's DolbyD 5.1 decoder.

    I was shocked at the results. When I switched from the digital output to the analogue output my rear speakers came alive in a way I never thought possible. The dialogue was cleaner and more focused. Each speaker seemed more distinct and seperate. The bass was tighter. All around I found it to be a more pleasant listening experience.

    The problem is that the SD4800 DVD player has NO bass management, whatsoever. My B&W bookshelf speakers seemed to be working overtime as a result. Plus, my sub was nearly (not completely) innactive.

    Still the sound was always significantly better whenever I switched from the digital-coax over to the analogue outs. Much better!

    I feel I need to get to the bottom of this. You see, it's driving me crazy knowing that all this time I haven't been realizing the true potential of these movie soundtracks.

    Call me crazy, but I would prefer to feed a digital signal to my NAD receiver than to use the analogue signal.

    Questions:
    Is it a cable issue? Is my digital-coax cable not feeding my NAD receiver a good enough signal? Should I purchase a better digital-coax cable? Or, is it that the NAD's decoder is inferior to the Toshiba decoder? Or, am I missing something?

    Please advise.

    Thanks!
     
  2. Scott Merryfield

    Scott Merryfield Executive Producer
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    Did you calibrate the speaker levels via your Toshiba DVD player's on board DD/DTS decoder? Also, have you calibrated your speakers via your NAD receiver for use with its DD/DTS decoder? If not, your surround speakers may appear to sound "better" with the DVD player's decoder because they are louder than they should be (or, at least, louder than via the NAD's DD/DTS decoder).
     
  3. Michael Reuben

    Michael Reuben Studio Mogul

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    As an extension of Scott's question: Had the NAD been properly calibrated with an SPL meter and test tones? If not, it's possible that the deficiencies you've now identified in the NAD's playback are simply a result of the levels for rear and center speakers being set too low.

    M.
     
  4. Cliff Olson

    Cliff Olson Stunt Coordinator

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    I did the same thing just 2 weeks ago, after purchasing a used Sony TA-P9000ES. I knew SACDs would be amazing in 5.1, but even movie soundtracks sound much better being decoded inside the DVD Player - not to mention redbooks. I've had it calibrated with an SPL Meter - the Lexicon DC-1 Preamp, and the Sony DVD Player, so levels are the same. It's just the different DACs, I guess. Glad you experienced the same euphoria I did, Jeffrey! Oh, and to answer a few of your questions:

    No, I'm sure it's not your coax, because I'm using -- was using, a Kimber D-60 Coax (considered by many to be one of the best).
    I suspect, your DACs in the Toshiba are superior to the ones in your NAD.
     
  5. Jeffrey Wiffen

    Jeffrey Wiffen Stunt Coordinator

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    Thanks for all the responses. I can't say that I am impressed though. It pisses me off that my $200 DVD player has better a decoder and/or DACs than my $1500 receiver.

    I mean, the difference was night and day! It's not just that things were louder as Merryfield suggested. It was just "better" in every possible way.

    Unfortunately, my DVD player does not have a DTS decoder. So I will still have to use my digital-coax connection for these tracks.

    I still think I may demo a couple different coax cables (maybe even a tos-link optical cable) to see if I can improve the sound using my receivers onboard decoders.

    My only issue still, is the bass management issue. The sub only became active occasionally, and when it did was only minimal. However, my bookshelf speakers setup (B&W DM303s) have never sounded better! They put out some serious bass, for their size.
     
  6. Vin

    Vin Supporting Actor

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  7. Cliff Olson

    Cliff Olson Stunt Coordinator

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  8. Scott Merryfield

    Scott Merryfield Executive Producer
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  9. Michael Reuben

    Michael Reuben Studio Mogul

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  10. dave alan

    dave alan Second Unit

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    One further thing to consider is jitter
    which is introduced by the digital coax or toslink cable when sending the digital signal from your player to an external DAC (your NAD)

    Although jitter is generated by other parts of the signal chain, this digital cable, or transmitter induced jitter is eliminated by letting the player do the conversion to analog.

    I also hear a difference and have used the 'bypass' mode on my Pre-pro exclusively for about a year. There are other sonic advantages with analog connections as well.

    What you sacrifice is DD EX and DTS ES as well as matrixed modes like Logic 7 and Cirrus Extra (6.1 and 7.1), but for 5.1, assuming your player has good DACs, analog is the way to go, for me.

    Also, speaker distance placement is more critical, as you lose time alignment, but, to me, digital time alignment on most pre pros isn't all that and placement is always critical anyway.

    I suggest the Outlaw Audio ICBM if your pre has no analog BM. It's a quality analog BM device at a steal of a price.
     
  11. Cliff Olson

    Cliff Olson Stunt Coordinator

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  12. Andy_A

    Andy_A Second Unit

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    1. Buy a $12 Canare digiflex gold digital coax and do not look back. Unless you have a ground loop issue--then buy a $20 toslink.

    2. For playback, I normally do not notice any difference playing back dd/dts sources from dvd vs. preamp assuming I have correctly set the listening levels with a spl meter. The ICBM is highly recommended, though. With this device, you should run all dd/dts/dvd-audio from the dvd player with speakers set to "large". The above posts are correct in saying the differences you are hearing are due to set up in the pre/pro. Hope this helps.
     
  13. ReggieW

    ReggieW Screenwriter

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    I have a NAD T762 and Denon 2900 and ALWAYS allow the T762 to do the processing for movies. For one, I then have real bass management and don't run into those problems like I do with multi-channel hi-res music when using the analog outs. The Denon 2900 DOES have a better DAC than the NAD, but the greater flexibility, ease of use, and better bass management, makes up for any perceived audio improvement that the 762 may appear to offer.

    Reg
     

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