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Need Help Playing Back Recordings To a Jury In a Courtroom

Discussion in 'Recording' started by Unregistered, Apr 12, 2011.

  1. Unregistered

    Unregistered Guest

    Hi all,
    I'm with a large metropolitan district attorneys office and we're having a problem playing jail house/911 tapes to juries. The recordings come to us on audio CDs and the best we've come up with is playing the recordings on our laptops, through external laptop speakers, next to one of the courtroom microphones and thus through the courtroom's speakers. The recordings are fairly low quality to begin with and our setup makes it worse. The courtroom is full of Shure MX418d/c microphones that plug into what i believe are called XLR outlets, and so my question is, is there a cable that will allow us to run sound directly from the laptop (via the lineout maybe?) to the courtroom speakers via these XLR jacks? Did a google search for line out to XLR, and the results were just beyond me. Any help would be much appreciated!

  2. Boswell

    Boswell Distinguished Moderator Resource Member

    Apr 19, 2006
    Home Page:
    You can't run a signal from your laptop or a CD player directly to an XLR socket designed to take a microphone, since the signal level and type is all wrong.

    Assuming it's only a mono signal that you want replayed (L or R channel), there are two easy ways this could be done:

    (1) Use a Direct Input (DI) box. You would need one that could accept a headphone signal out of a laptop or CD player. The DI box converts the high-level signal to the low-level balanced type of signal that a microphone puts out, so the PA system thinks it simply has the signal from another microphone. Here is a link to a suitable passive DI box. You would need a cable with a stereo minijack plug on one end and two 1/4" TS jacks on the other (L and R channels). You would use either the L or R channel plugged into the DI box.

    (2) Find the PA mixer/amplifier in use in the room and re-plug one of the XLR cable inputs to be a line-level (not microphone) input. At the open end of the cable, you would plug in a mono jack socket-XLR adaptor, and then by using the right sort of cable, you should be able to connect CD player.

    My preference would be to go for the DI box, as it is portable and needs no re-patching of the PA mixer. If you need stereo (or stereo reduced to mono), things are a little more complicated, but still workable.

    Let us know if you think this would work for you or if you have questions.

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