Preventing ground loops ("hum" noise)

If you want to prevent -or are trying to eliminate- acoustical or visual intereferences, “hum”, ground loops…
make sure all your devices (and any devices electrically connected to them in any way) are powered by the same power line.

For example, our live shows support music events and are sound-reactive. So there always will be at least one audio cable that connects our video equipment to the audio mixer being used by DJs or musicians. To prevent ground loops, we put all our equipment -including projectors and TVs- on the same power line as the musicians.

In our experience, event promoters and venue technicians or owners will assume video equipment should go on the same power lines as lights.
If you connect to their sound system, you may have to explain why this is not the case. We never had to say more than “we know this is the way to go to prevent ground loops” but YMMV.

Also this will likely require some additional resources (extension cords and/or power strips, basic knowledge), additional time and possibly some planning (especially if other artists are involved in the same event) so take that into account: DIY (do it yourself) or put it in your tech rider and make sure they care about it.

We empirically verified this approach in a music club that has a very good sound system and an electric system correctly set up. We had connected the projector to our equipment, and we had powered it up from a separate power line. The sound system was emitting a noticeable (and unacceptable) “hum” noise, which disappeared as soon as we put the projector on the same power line as our equipment.
We have been following the same approach since, in at least 4 other different music venues and :crossed_fingers: we never had issues so far :crossed_fingers:


…yep! - just to confirm that that is the trick (we are also using successfully for 25 years plus now)…

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i just ran in to this today actually! it’s a tricky one though because our stuff is running off of generators, and it’s not always possible for the video stuff to be wired to the audio stuff directly. gunna be grabbing a ground loop isolator for our next event.

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