XLR and DMX cables

Discussion in 'Live Sound [BG]' started by Jaygetsreal, Jun 18, 2021.

  1. Not sure if this has been covered in previous posts - couldn't find anything.
    We've been repeatedly told not to use XLR mic cables for linking up DMX lighting fixtures, despite their being electrically the same. But I confess I have often cheated without any problems.
    What I would like to know is has anyone had experiences which would confirm that swopping cables between audio and lighting, and vice versa, can damage gear or fail during a gig?
    Also if any of you brainy types has the figures on signal frequency, capacitance, max cable length, current etc in the cable in each application I'd be interested to learn more.
     
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  2. s0c9

    s0c9 Supporting Member

    Jan 9, 2014
    Ft.Worth/Dallas
    1964 Audio artist, Fractal Audio Beta Tester
    Done the same swap for years on my DMX stuff..never had a problem.
    But then, it wasn’t a full blown stage lighting rig. <shrug >
     
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  3. JohnMCA72

    JohnMCA72

    Feb 4, 2009
    I tried sending DMX down a spare channel on a 100' audio snake once & it didn't work at all.

    I have used DMX cables in a pinch for audio with no noticeable problems.

    DMX cables have a much lower capacitance than standard audio cables, which is necessary for high speed serial data. Specs are available online if you want to research further.
     
    s0c9 likes this.
  4. Jason Stock

    Jason Stock Supporting Member

    Aug 13, 2019
    Edmonton
    I have used some audio cables on my lighting in the past (in a pinch) and only one time on my older lighting rig did I have an issue, but it may or may not have been cable related. I just put a DMX terminator in the last light in the chain and it solved the problem.

    Can't say I have ever used DMX cables for audio. Probably never will as I keep my sound and lighting gear separate and have lots of extra XLR's in the trunk
     
  5. sharpiemarker

    sharpiemarker

    Feb 15, 2013
    Montreal
    I’ve never used DMX for audio no experience there. XLR for lighting isn’t a problem it’s just not a best practice. You will run into issues when you have larger set ups and long runs. ex: a few lights at the end of the chain not turning the same colour as the rest or one randomly strobing. I have never heard or seen anything get damaged. There are a lot of smaller venues/production/event companies in the world that don’t even have any dmx cables in their shops
     
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  6. Wasnex

    Wasnex

    Dec 25, 2011

    DMX and mic cables are not the same. The DMX cable is made to a higher standard. In many instances you can use mic cables in a pinch, but the risk of problems is higher. Using a DMX termination plug at the end of your signal chains is also recommended to enhance reliability, but I would bet that few people actually use them.

    I have run DMX down a 200' snake with no problems. But it was a top of the line, pro Whirlwind and I am pretty sure it was rated for DMX.

    The longer your runs and more complicated your setup, the more likely you will experience problems with standard mic cables. If you are running a large rig, fixtures early in your signal path may work fine, fixtures in the middle may be erratic, and fixtures at the end may be totally unresponsive.

    From: XLR vs. DMX | What is the Difference? | ShowMeCables.com

    DMX has a higher impedance (110 ohms) than XLR (75 ohms). This means that XLR uses different signals than DMX is built to handle. An XLR cable can transmit a DMX signal, but not very well.
    Here is another article if you want to read more: XLR vs. DMX Cables: What's the Difference? | Hosa (hosatech.com)