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Activity Forums Blackmagic Design open gear de-embedder cards making nose???

  • open gear de-embedder cards making nose???

    Posted by Patrick Spohrer on May 26, 2012 at 4:54 pm

    We are using a Blackmagic Design open gear frames
    with 8 BMD cards in it. In it are five de-embedder cards (what are
    call “SDI to audio). We also have one BMD Open Gear sync generators.
    We are using Panasonic HD Cameras (AG-HPX370’s and AG-HPX250’s). The
    switcher is a For-A 1.5m/e 20 input HD-SDI switcher. The mixer is a
    Mackie 1604VLZ Pro 3/

    The HD-SDI output of the cameras goes into the de-embedder cards. The video
    then goes on to the switcher. The audio comes out of the de-embedder card
    and goes into the line-level inputs on the Mackie mixer. We know our
    wiring is correct.

    The system de-embeds the audio perfectly. However, when we turn one of the
    cameras off (for example to change batteries), the audio goes insane –
    making a clicking sound into the mixer. We believe there is a problem
    with your cards. When you pull video from card it should just go quiet.

    all 4 of the cards do it and one of the cards is DOA.

    any ideas?

    -patrick

    Patrick Spohrer replied 13 years, 11 months ago 3 Members · 3 Replies
  • 3 Replies
  • Jeff Hartman

    May 28, 2012 at 3:05 pm

    Just to clarify: when the SDI feed goes away, do you get one pop and then silence, or is it continuous noise?

    A single pop isn’t necessarily a surprise: the D>A converter will be going almost instantly from its last known value to zero volts. But that should be the end of the noise (until the SDI comes back on).

    — Jeff

  • Justin Strauber

    May 28, 2012 at 4:28 pm

    Yes, the BMD De-embedders tend to make random popping noises when there is no input signal. If your input signal was just black with no audio, you’d get silence. Unfortunately when there is no signal, the card seems to interpret the lack of signal as ‘noise’ and make random popping noises. Our Ross switcher sees no input as digital ‘snow’ and I assume the BMD devices do something of the same.

  • Patrick Spohrer

    May 28, 2012 at 4:45 pm

    It is a continuous clicking sound.

    -patrick

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