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M-S Decoders?

Discussion in 'Recording' started by mckojack, Nov 18, 2003.

  1. mckojack

    mckojack Guest

    Anybody know of a reasonably priced outboard M-S decoder box with line level(+4)XLR ins/outs?

    AEA sells one that has some extra tweaks(width control, etc.) but it runs at about $600 list.

    I've seen some partial circuit designs posted. They seem fairly simple, but they've been either unbalanced or incomplete.

    Any thoughts?
  2. RecorderMan

    RecorderMan Distinguished Member

    Mar 28, 2001
    any three channels with polarity reverse on one and the ability to pan will decode M/S (analog or digital)...when spend money on a dedicates matrix?


    M channel: Pan center.
    S channel number one: Pan left; polarity normal
    S channle mult( a copy or mult of the S channel): Pan right; polarity reversed.

    So, M is up the middle and gives you your mono center/image. The Left S+ and right S- channels give you your stereo/side information.
    Play with the balance, though the combined S+/S- channels can start around -3db relative to the M channel.

    [ December 02, 2003, 12:28 PM: Message edited by: RecorderMan ]
  3. mckojack

    mckojack Guest

    Is that all there is to it?

    Are there any benefits of a stand-alone matrix?

  4. AtticMan

    AtticMan Guest

    The only advantage I can see of a dedicated M/S decoder would be in a live-to-two situation, where you need to get the correct stereo imaging onto tape, rather than decoding it later during mixdown.

    I've only used M/S a coupla times, but in both instances I decoded after the fact using three channels on the desk and hard panning/flipping polarity, as described above.
  5. jdier

    jdier Active Member

    Mar 20, 2003
    Home Page:
    Here is a decent article on the subject along with some links for DIY decoder boxes.

  6. Marik

    Marik Guest

    For DIY decoder you can also check PAIA kit at:


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