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Automatic Volume Leveling (AVL)

Discussion in 'Electronic Repair' started by Chuck, Dec 21, 2007.

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  1. Chuck

    Chuck Guest

    It's nearly too late now since the new TV's have AVL built-in to adjust
    volume increases during commercials, but I am very surprised nobody ever
    built a "good" add-on aftermarket volume-leveler all these years. Why would
    it be so hard to build a good yet inexpensive one?

  2. N Cook

    N Cook Guest

    I'm quite happy , if watching off air, to zap to another channel for a few
    But I would like an auto insert "PIP" of the otherwise viewed channel so as
    not to miss the after-ad return.
  3. Have you heard the results of these built in ones? Ok, I suppose, if your
    standards stop at AM radio quality.

    The snag with this sort of device is it has to have a fast attack time to
    work and a fairly slow recovery. And will work on any programme peak - not
    just commercials. Make it fast attack and fast recovery and background
    sounds will pump up and down - most unpleasant.

    The *only* way you can get smooth transitions between the vast variety of
    programme material - and the variety of commercials - is buy having a
    human rehearse that transition and adjust things accordingly. (Advertisers
    - who fund the programmes - would not be happy if their product was
    quieter than the progs). But playout systems are largely automated these
    days to save on labour costs.
  4. msg

    msg Guest

    I am replying without first searching the web, but I do remember seeing
    adverts over the years for a variety of ALC devices for TVs; the good ones
    IIRC used to inspect the vertical interval for clues to program changes,
    and also used timing heuristics to predict commercial placement. I
    believe that such a device using learning algorithms with human training
    input would have been _very_ effective, after all, at least in the U.S.
    on major networks, a human can very easily predict when commercials occur
    and when the level is excessive.


  5. hr(bob)

    hr(bob) Guest

  6. jakdedert

    jakdedert Guest

    Here in Nashville--and I suppose many other places--there are a lot of
    'local option' commercials. IOW, there's a commercial on the satellite
    feed, but it gets pre-empted by one chosen by the cable operator.

    Here, the audio levels on these local options commercials is all over
    the place; usually WAY too loud, but sometimes (blessedly) barely
    audible. You can tell they're local option because either the subject
    is a local business, or sometimes you see just a 'blip' of another
    commercial before they cut to the replacement.

    Very annoying when you're listening to a movie with the volume up, or
    you have the TV on as background to fall asleep by....

  7. Chuck

    Chuck Guest

    That's the same problem we have and it drives us crazy! Does anyone have a
    newer TV with the built-in AVL feature, and how well does it work?
  8. jakdedert

    jakdedert Guest

    You can call your provider. So far, I haven't gotten that far, but
    IIRC, there are regulations about relative volume...might not apply for
    cable, but over the air....

    The issue is with the (less than) technical help the cable company (in
    my case ComCast) employs to drop in the commercials.

  9. Jamie

    Jamie Guest

    TV is advertisements! They don't make money from their viewers by you
    watching movies. They know you'll turn up the volume to
    listen to the movie and get blasted from the commercials which places a
    subliminal impact on your brain in hopes that when you are in the store,
    you'll have some interest in that product and have no idea why!

    You must remember, shock and fear are the best methods for programming
    the brain! That is, if you got one!
    It's all about the big green! or what ever color it is! :)

    "I'd rather have a bottle in front of me than a frontal lobotomy"

    "Daily Thought:

  10. jakdedert

    jakdedert Guest

    Except when they make it so obvious that you have no doubt as to what
    they're doing. Annoying your clientele is not a formula for increased

  11. clifto

    clifto Guest

    You mean "to play with all the shiny buttons."
  12. It's a world wide thing. I recently got a satellite receiver with dish
    rotator and can receive some 5000 programmes. If you can call them that.
    ;-) And most attempt to get the picture levels near right but seem to let
    the audio look after itself. Peak levels vary by over 30dB, some stereo
    ones are out of phase or only transmit one leg and high levels of
    distortion tend to be the norm with the smaller channels.
  13. [/QUOTE]
    Mine has it but it sounds horrible, so it's never used. To be fair I'm an
    audio type working in TV production so may be more critical than some.
  14. The big snag is there's no way of measuring loudness accurately. It's the
    holy grail to develop a device which does so to all's satisfaction.
    Conventional metering systems can read peak or average levels but don't
    take into account the perceived loudness to the ear - or rather brain. And
    the other big snag is that what is too loud to one isn't to another - just
    think about the music your kids listen to. ;-)
    Again it depends on the programme preceding the ads. If a brash game show
    etc chances are the ads won't sound louder. If some drama with a poignant
    end chances are they will.
  15. Guest

    In February of this year, I bought a new Toshiba 27 inch flat screen tv
    set.The tv set had the AVL feature, I could click on it (in the menu)
    and use it or not.About two days later the screen developed a
    blob/blotch on the bottom left side of the screen.I took the tv set back
    to the store and I paid about $34.00 difference in price for a new Sony
    Trinitron Wega 27 inch flat screen tv set.The Sony gets a much better
    picture than the Toshiba did, but the Sony doesn't have the AVL
    feature.I use the Mute button (or change channels for a while) on my tv
    remote when most commercials are on there.I think the higher price Sony
    tv sets do have the AVL feature.Yep, some tv commercials are wayyyy too
    loud.I need something that looks sort of like a wrist watch that has a
    big tv Mute button on it.
  16. jakdedert

    jakdedert Guest

    Huh uh. We're talking about levels, like you said, varying by 30 dB. I
    haven't measured it here, but it could be that much. It's about local
    cable companies charging $55/month for 'basic' cable, but not hiring
    somebody to simply *listen* to the feed when they dump in commercials
    which are wildly different in level. It's NOT a matter of opinion when
    you turn the volume to a point where it's barely background level, and
    then get jolted out of your sleep by a literally blaring commercial.

    It's mostly about money and an unwillingness to pay for technical
    competency. The over the air stations, when I listen to/watch them,
    don't have this problem to nearly this degree.


  17. Ross Herbert

    Ross Herbert Guest

    I don't think it is very easy to design what you are looking for - at
    least not so it is affordable.

    As to why do the ads seem louder? - read this

    In fact the maximum level of the ads is not greater than the normal
    program material, its just that the ad level is more constant per unit
    time, thus the average level is greater than that of the program
    material. Advertisers are aware of this trick so they ensure that the
    dialogue is constant throughout the ads.
  18. jakdedert

    jakdedert Guest

    That's probably true of national network shows broadcast over the air.
    I was referring to 'local option' commercials dubbed in by a cable
    company. As I said earlier in the thread, often the difference in level
    is *downward*, not louder.

    I've been a sound engineer for over 30 years. I know what loud is, and
    I know what compression sounds like.

  19. Crikey - I was talking about between different channels on satellite.
    Don't think I've noted that on any one channel.
    Think you'll find even the major channels don't do that either these days.
    Trouble is it wouldn't be one person but a team to cover 24/7 - and an
    expensive team of skilled personnel to work effectively. Then there'd be
    the problem of an advertiser claiming his ad didn't sound loud enough if
    it were altered. And they are the paymasters - not you. Unless legislated
    They rely on the material being transcribed into their server at the
    correct level - or being supplied as such on whatever material they
    transmit from. And as I said thereby is the problem as relative loudness
    depends on programme content.
    I'd rather not watch TV that sends me to sleep. ;-)
    Indeed - but plenty still complain about the major channels where more
    care is taken. And have done (in the UK) since commercial TV started. ITV
    in the UK do have a maximum peak level for commercials some 4dB lower than
    progs. Which mostly works - but not always.
  20. It's a bit out of date.
    There's no reason why you can't do the same thing with prog material. As
    indeed is done with things like game shows and sit coms. But it is rather
    inappropriate for serious drama, etc.
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