LaserDisc Digital Sound Question

Discussion in 'Playback Devices' started by threephi, May 11, 2012.

  1. threephi

    threephi Auditioning

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    I have an old LaserDisc player without any sort of digital sound capabilities. I own quite a few other titles on LaserDisc and can play them fine, however I recently picked up a bunch of discs at a garage sale, brought them home, and they play with a buzzing out of the right channel. Switching to left only eliminated the buzzing, but didn't actually give me the sound of the movie because right was a commentary track.
    Besides digital sound capabilities am I missing something else here? What good are these discs if you can't really watch them with a conventional machine?
     
  2. Gary Seven

    Gary Seven Grand Poo Pah

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    The later LDs have both digital and analog sound. The commentaries were put on the analog tracks leaving digital tracks for the movie themselves. In those cases, you are SOL. You need a LD player with digital sound. However, not all LDs have commentaries and in that case, you can hear the analog for the movies. Nothing wrong with the discs.
     
  3. Steve Tannehill

    Steve Tannehill Ambassador

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    You have an analog-only LD player. The discs with the buzzing out of the right channel are AC-3 encoded (that's how LD implemented Dolby Digital, by using one of the analog channels).
    By the way, welcome to HTF!
     
  4. Chris Brown

    Chris Brown Stunt Coordinator

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    Are you saying that your player doesn't have a digital output or simply doesn't process the digital sound at all?
    There are many players without a digital output, but that still process the digital sound. In that case you will usually have more than one set of analog outputs on the back.
    Yeah unfortunately once PCM digital stereo tracks became the norm, most newer discs contain only commentary tracks and modulated AC3 on the analog tracks.
    Really if your player is old enough to not process the digital signal at all, then it's probably not a very good player. Laserdisc video is analog so the player has a huge impact on the video output, similar to a record player playing a record. If you have a good library of discs, you might seek out a newer player on craigslist or similar. You could probably find a new one for ~$30 with digital output, after which you can take advantage and enjoy the amazing PCM tracks. On many discs like Top Gun, it's the same Dolby Surround track that they actually played in the theaters and works GREAT with a pro-logic receiver. Others like Apollo 13, with seemingly no dynamic compression, make for some breathtaking scenes. The Saturn V launch scene is what I refer to as the Grim Reaper of subwoofers.
     
  5. threephi

    threephi Auditioning

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    Yes. The player is so old that it does not support PCM audio at all. Taking your recommendation, I just ordered a player from eBay which supports PCM audio and came with the barcode scanner and IR remote for under $100.
    I understand what is going on, but I don't understand why they'd do that. The commentary isn't that important and the original FM audio tracks on the LaserDiscs were the "compatible" format for playback. I remember Beta tapes sometimes coming in HiFi format with commentary on one of the stereo channels (or dubbed in another language), but the monaural audio was still the main soundtrack.
     
  6. threephi

    threephi Auditioning

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    I guess another thing that bothers me is the fact that the back of the jacket doesn't even mention the fact that the disc doesn't include FM audio of the movie. There's a description of the sound settings, but it just mentions that you should select 1/L for monaural playback, but fails to mention at it's the commentary channel.
     
  7. Chris Brown

    Chris Brown Stunt Coordinator

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    AC3 is what messed it up really. They could have simply put the AC3 in-place of the PCM tracks but those were the most common tracks used at the time and not everyone even had an AC3 decoder at that point. They actually did this with DTS laserdiscs; there is no PCM on those discs as the DTS occupies the digital channels. Fast forward to today and most can't even make use of the AC3 tracks since it requires the use of an AC3 Demodulator which these days are more expensive than the players...
    But the AC3 on a laserdisc is only 384kbps anyway, lower than the DVD standard of 448kbps. The CD-quality Dolby-surround encoded PCM tracks are still your best bet.
     
  8. SilverWook

    SilverWook Cinematographer

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    Some old pre-digital sound players are still useful. I have an old top loader made in 1983 that runs as good as they day I got it in 1986. It plays problematic discs cleanly that are riddled with mild rot that are unwatchable on my newer players.
     

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