Why does LASERDISC dd 5.1 or DTS sound better than DVD in the same sound format?

Discussion in 'Archived Threads 2001-2004' started by steve jaros, Apr 20, 2002.

  1. steve jaros

    steve jaros Second Unit

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    Last night i watched a laser disc - star trek 'generations' for the first time in probably 3 years. While the picture quality was of course far inferior to the DVD version (which i also have), i was reminded of how much better the laserdisc sound was. The sound was huge, crisp, booming, and enveloping.

    I have 15 movies in both the LD and DVD formats that are both encoded in either DD 5.1 or DTS. In nearly all cases, the LD sounds better. In a couple, the sound is equal. In no case does the DVD sound better. Of course, this is just my personal opinion, so i want to know if anyone else feels the same way (or not).

    Also, is there any technical difference in the way sound is encoded on laser vs. DVD that could account for the difference?

    BTW, i've owned a DVD player for 5 years now and was always on the "dvd side" in the old DVD vs. LD format wars. And i've thought since day 1 that DVDs looked better. So if anything my general 'bias' is pro-DVD.
     
  2. Jeff Kleist

    Jeff Kleist Executive Producer

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    From what most have been able to gather, the LDs used the theatrical DD/DTS tracks while many DVDs have been remixed for near field (home) listening environments

    Bits are bits, so if no remixing is done, they should sound identical.
     
  3. KeithH

    KeithH Lead Actor

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    With so many movies being reissued on DVD (i.e., second versions on DVD), I wonder if high-profile films will be reissued with the theatrical soundtrack. I assume this is possible, at least with some movies (i.e., no space limitation on DVDs).
     
  4. RichardMA

    RichardMA Second Unit

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    There is a better quality to some parts of the sound

    of laserdisc DD tracks than DVD DD tracks. This is

    pretty clear to people who have compared them, but it

    is not 100%. The mid-bass on LDs seems more apparent,

    but the upper frequencies on DVD seem clearer. But it's

    generally the mid-bass impression that most people seem

    to notice. Kind of like going from a Yamaha receiver to

    a Denon. However, this is contingient on your laserdisc player/DVD player being roughly equal in terms of what they output.

    If the digital stream is fed to the same preamp/reciever,

    then the comparision is valid. If you feed out analog

    tracks from the players, then it's hard to determine if

    the comparision is correct.
     
  5. steve jaros

    steve jaros Second Unit

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    Richard - FYI in my setup the digital stream is fed to the same receiver.
     
  6. MTrotter

    MTrotter Stunt Coordinator

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    I have the same situation with Jurassic Park, but I don't have DD or DTS on my LD player. The LD analog output is simply vicious when the big T-Rex snorts and roars after the Explorers stop running, with tremendous clarity and room shaking bass. The DVD seems muted and constricted by comparison. I have never been able to get my DD DVD to approach the dynamics of the LD. I do agree that DVD video quality is far superior for most films, although Jurassic Park is close.
     
  7. Marc_E

    Marc_E Supporting Actor

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    One major reason is that , at least in the case of LD DTS (am not sure about DD but suspect it is true there too), the audio is full bit rate, not compressed.

    Marc
     
  8. Lewis Besze

    Lewis Besze Producer

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    A couple of misconceptions here.
     
  9. Jin E

    Jin E Second Unit

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    On a slightly different note...

    IMHO of course, but a lot of movies even sound better with their PCM digital stereo tracks and DPLII then they do mixed in DD5.1. DPLII can really make those old PCM tracks come to life!
     
  10. MTrotter

    MTrotter Stunt Coordinator

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    Jin, that is what I was referring to above about Jurassic Park. And I just have regular ProLogic.
     
  11. Michael Reuben

    Michael Reuben Studio Mogul

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  12. Vince Maskeeper

    Vince Maskeeper Producer

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    This question comes up often- but I'm leaning towards issues of encoding methods rather than the playback carrier. In theory, dd ld and dd dvd should be identical at the playback stage.
    This makes me wonder about the steps going from theatrcial masters (as uncompressed mags if that is the multichannel stem source) and how they are currently prepared versus how they were prepared for LD.
    I assume in most cases the theatrical mix is actually ported almost directly (with a few compenasations made for difference in surround levels and X-curve adjustments) from the mags. I would assume they're being sent into a sounddesigner/protools environment- locked to pocture- and exported to an AC-3 file directly, or played into an encoder unit.
    This would be different from how LD versions would have been done in the early/mid 90's. I'm wondering if maybe some small changes in the signal path getting to DD format for DVD has changed since the LD days and no one has really complained so it has stood.
    I know there are some issues about clarity in 1st octive audio in protools environments (if you're interested, you could read this discussion on the digi site about some a-b comparisons being done vs 192k hd protools systems).
    Again- I really think it's coming down to prep of masters rather than playback formats- and I'd be interested (Still, 6 months after I mentioned it the first time) to hear from pros on exactly how soundtracks are prepped today for DVD vs yesterday for laser.
    -Vince
     
  13. Dwayne

    Dwayne Supporting Actor

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    I have pointed this out before and I still don't know the answer. Those who do know the answer haven't said shit.
     
  14. Philip Hamm

    Philip Hamm Lead Actor

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    I tend to agree with Vince's theory. LD DD is the same bitrate as theatrical DD. I'm sure that LDs are direct bit for bit copies of the theatrical DD copies (with compensation for rear channel volume - except on a few early DTS Lasers). DVD is much a different animal entirely.

    Agree the Jurrasic Park PCM LaserDisc in ProLogic is stunning, one of the best ProLogic sources I've ever heard. Easily comparable to the also excellent DD version. This (along with Lion King) was my reference demo disc before I got DD back in the day.
     
  15. Michael Reuben

    Michael Reuben Studio Mogul

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  16. DaViD Boulet

    DaViD Boulet Lead Actor

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    Jitter.

    For those audiophiles out there. Jitter can affect not only the d/a sound of linear PCM, but even compressed digital formats. Decompression aids in jitter reduction bcs there is some necessary buffering etc., but as long as the master d/a clock is synched in some way to the incoming clock of the compressed bitstream (the way that almost all surround decoders/d/a converters work) you will STILL have some jitter affect the final sound as the master clock governing d/a conversion. Audio Alchemy made a reclocking jitter filter specifically for compressed bitstreams like DD and users who put it in the path of their digitial output of their DVD player *all* heard improvements...some quite dramtic.

    This is my personal opinoin as to why DD (and even PCM) on DVD doesn't sound up to snuff with the same bit-rate data on LD. LD has always been an exremely low-jitter medium. If you want to hear the difference, get an LD with some PCM of a music-video that has the same PCM audio that you have on the CD album. Play them through the same d/a converter. Almost always the LD *blows away* the CD sound. It's smoother, more natural, more open...all that audiophile stuff.

    -dave
     
  17. RobertR

    RobertR Lead Actor

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  18. Shane Martin

    Shane Martin Producer

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    I'm in total agreement with RobertR although I won't listen to a double blind test as I could care less.

    The mix is the reason and well I prefer the Laserdisc mix.
     
  19. DaViD Boulet

    DaViD Boulet Lead Actor

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    I'm sure the different mixes are also a contributing factor (especially with things like the JP DTS debacle from a while back).
    But I'm tellin' you, jitter does have an audible impact as well [​IMG]
     
  20. Daniel L

    Daniel L Stunt Coordinator

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    One of the primary reasons for the difference between DD 5.1 on LD and DVD is this: Generally, the 5.1 on a DVD is mixed so that it will down-mix into pro-logic for the average, non 5.1 set up.

    This comprimise frequently leads to a lack of bass on 5.1 DVD's when compared to thier LD counterparts.

    From day one, Dolby Labs has encouraged all of the studio to provide both mixes on DVD's, but unfortunately most studios do no do this.

    Even then, sometimes the mixes just aren't up to snuff. I still trying to figure out how Fox has blown a few of thier mixes, such as True Lies and Phantom Menace. These both have 5.1 and Dobly Surround Mixes, but it almost sound like they made the down-mix version for the 5.1 tracks.

    Daniel L
     

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