Help with audio sync compensation?

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  • frascati
    Member
    • Nov 2009
    • 82

    Help with audio sync compensation?

    Have a Samsung pn50c550 plasma.

    Ext Aud Out signal from the back of the set is ahead of the internal speaker's output. No measurement, but guessing that it's on the order of 150 to 200ms or so. Audible echo between headphones plugged into this jack and sound coming from the internal speakers.

    As much as it's anathema to any HT purists, I am rather fond of the simplicity of running the internal speakers with support from a small external powered sub. I really would like to avoid investing in an expensive AV receiver only to address this issue. I also happen to be using this output to feed a very small amp for a hearing impaired member of the family. So that slight delay is affecting their listening as well as being slightly ahead of the display.

    There are no menu adjustments for correction. A search has provided a few options for simply correcting the grossest error produced by the set itself, setting and forgetting. I'm not concerned with the less than 50ms sync problems that some consider necessary to correct with remote control, on a regular basis, from their armchair.

    The cheapest is a digital delay effects pedal. Behringer, naturally, has the least expensive. A DD400.

    It's not an ideal fit. It needs some attenuation to handle the output of a powered aux aud jack. It also is not intended as a simple delay, so it's echo control needs to be set as low as possible. The DD400 can be had as cheap as 28 dollars Amazon. It also appears not to be true stereo so two would be needed.

    The next possibility is the Behringer FBQ100 Shark feeback destroyer.

    Single channel, so two are needed. Comes to 180 dollars for two. Way too many options and equipment and cost for this need.

    Then there is the Felston DD740, which I already kind of referred to.

    240 dollars, memory sets, remote control, digital readout. Nice stuff. Extreme overkill for this problem I have.

    Finally there is EXACTLY what I need, but irritatingly expensive at 90 USD for two dollars worth of parts in a tiny plastic case.. just can't do that on principle. Just can't. Hope you understand.


    So, short of doing something insane like trying to build my own via Digikey and pouring days worth of study and frustration into this, can anyone suggest a simple, cheap, effective, set and forget, method of correcting this delay?
  • madmac
    Moderator Emeritus
    • Aug 2010
    • 3122

    #2
    Are you sure that you have looked properly in the TV's sound menu?. This phenomenon is VERY common with the new TV's because they are digital in nature and the sound is finally converted to analog and sometimes this causes these types of delays. Therefore, the TV manufacturers en-corporate an adjustment field in the 'sound' part of the menu for this prroblem. That adjustment is sometimes called A/V sync or A/V delay or something like that. Look at your manual and TV sound adjustments to be absolutely sure ok??. My Sony HDTV has this feature and I have had to use it for the exact same reason you discuss above.
    Dan Madden :T

    Comment

    • frascati
      Member
      • Nov 2009
      • 82

      #3
      You are quite correct. The web is awash with comment on this. Yet I posted this question in the PN50C550 owner's thread at avsforum.com, a heavily trafficed site and thread, and got no response at all.

      I can only find a menu command for SPDIF (dig opt output) in the user menus which does sport a really easy to use, 10ms increment, delay slider up to 250ms.

      In the MUTE -> 1 8 2 ->POWER menu I can only find CONTROL -> SOUND -> SPEAKER DELAY NORMAL 20 which I assume is for the internal speakers. I cannot access the ADVANCED menu here. I can't find instructions for access on the web either. Is this adjustment in there possibly?

      I google this and discover that it's a VERY common concern.
      I only discovered it by accident. No doubt many people out there are using this output for sound, are unaware of the problem, and either using amps without the capability of correcting it or just ignoring it even if they do have settings for it. There are pages and pages of comment on the problem dating back almost 10 years. Yet it continues.
      Why on earth would sets continue to leave the factory like this if it is a setting that, in fact, could have been adjusted by the techs before ship?

      Is there ANY logical reason for the external audio jacks (which apparantly include the SPDIF digital outs) to be left unsynced when leaving the factory?

      Here is a review on a samsung plasma set from 2008. It's still uncorrected in 2011 for god's sake.
      "Great Plasma except for out of sync audio" on May 20, 2008 by nadouble Pros: Great picture Cons: Built in speakers sound is out of sync with sound from the stereo audio outputs Summary: The image on this plasma is great. I've upgraded from an HDTV ready Panasonic 32" CRT TV which was great but this is more than a step up. There's only one thing... The audio coming out of the rca stereo audio output is not in sync with the sound from the plasma's built in speakers.
      The web is chock full of such complaints. What is going on here?


      I'm not really that up to date on digital analog conversion. But Rather than try to adjust the analog outs...
      and since there is a really handy SPDIF adjustment (all this assuming that SPDIF actually does describe the optical audio outs behind the set and that they will function while the internal speakers are playing and not defeat them automatically when in use
      ... would it be easier to add a device to convert the optical aud outs back to analog for connection to the subwoofer and amp used for hearing impaired use?

      Here's a product but I'm a little confused by it's description. It appears that it converts analog to digital instead of the other way around?



      postscript : just found this from another forum
      I had same 'out of sync' problem with LE40B650. Service engineer has just corrected problem. He went through commands as described by BAZ-R. After advanced menu and keying 0000 the sound menu was not available. He went into CONTROL sub menu and then the Sound menu was available. The sound menu opens up options for audio delay etc. He set the 'Auxout delay normal' to 100 to match the 'Speaker Delay normal'. The sounds are now in sync. Good Luck
      Can anyone please help me find instructions for my set to accomplish this?

      Comment

      • madmac
        Moderator Emeritus
        • Aug 2010
        • 3122

        #4
        The part where you state "CONTROL -> SOUND -> SPEAKER DELAY NORMAL 20 "

        Did you click on that "Speaker delay normal" part to see if any other options come up?. It makes no sense that you would not be able to adjust this as it a common problem. Have you checked your TV manual ?.

        Let me know?

        Thx
        Dan Madden :T

        Comment

        • Kevin D
          Ultra Senior Member
          • Oct 2002
          • 4601

          #5
          It would be real easy and cheap to put a speaker-level to line-level converter on the internal speaker wires.

          Kevin D.

          Comment

          • frascati
            Member
            • Nov 2009
            • 82

            #6
            It would be real easy and cheap to put a speaker-level to line-level converter on the internal speaker wires. Kevin D.
            Could you give me a little primer on this? After digging deeper into all manner of approaching this, I'm more inclined to looking into this suggestion.

            Just bizarre that Samsung seems almost purposefully antagonistic to anyone trying to add any simple external audio devices to this. The simplest (analog) audio jack in the rear is not delay compensated to match the video. There is no way to internally adjust it. And the remote volume has no control over this output in any case.

            I don't even know if, after purchasing a required optical/analog converter to adapt the toslink jack for use on a "legacy" external amplifier (without it's own remote) I would be able to use the television's remote to control volume. Amazing. And it could have been so easy.

            So what would be needed in line between the speaker's terminals and a simple shielded stereo cable threaded out of the back of the set ending with a pair of male RCA plugs....

            1.. in order to be absolutely certain that doing so cannot damage the ampification circuitry within the television (barring my own cock-ups while in there)?

            2... in order to approximate the signal level optimal for AUX inputs on a standard stereo amplifier?

            This would, as you point out, be the most elegant solution to my needs. The remote would still command the volume level of the internal and external speaker without the need of a separate remote. The timing would be synced (at least within a few negligible ms). No need for any other devices.

            Comment

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