RF Interference with Monitor Speakers
An ongoing issue in my area is RF getting into… pretty much everything. I’ve already written about how I dealt with it in my mic lines, but I was also hearing it through my monitor speakers. It doesn’t affect the final bounced files, but over time the high-pitched whine and random chirps started to really get on my nerves, so I decided to fix it.
First step was redoing the wiring from interface to switcher to monitors with Canare 4-conductor balanced cable. That type of cable is great at rejecting interference, and while it did help, a bit of the noise was still there.
Next experiment: I took some copper fabric I already had and simply draped it behind the speakers. Instant success, the noise disappeared. The copper fabric was essentially acting like a partial Faraday cage, blocking the RF before it hit the speakers. From there, the goal was to make a more permanent and controlled version of that idea.
I also had to make sure I wasn’t blocking the rear ports or the heatsinks on the back of my Dynaudios. To do that, I cut a piece of copper fabric to size and lined the top and bottom with 18-gauge steel wire (the same kind you’d use to hang heavy pictures). In the center I glued a piece of cardboard. That combo gave the panel enough structure to curve and hold its shape without sagging over the heatsink.
To temporarily hold the wire/steel in place while I was working with the hot glue gun, I stitched it through the fabric at both ends and once in the middle. It doesn’t have to be pretty, it just needs to stop the metal from shifting while you glue. I tried doing it without the thread the second time and it actually worked pretty good too.
After that, I ran a bead of hot glue along the edge where the wire was and folded the fabric over it. I wasn’t sure how well the glue would hold long-term, but it actually worked really well and locked the metal inside a neat little hem.
Here’s what the panel looked like fully finished: a flexible copper “curtain” with just enough rigidity to hold its shape, stay clear of the heatsink and still hug the back of the speakers.
And here’s how it looks mounted on the speakers. I’ll probably clean up the mounting method later, but for now I’ve simply taped the sides to the speaker cabinets with black tape. From the top you can see how the embedded wire gives the shield enough rigidity to curve around the speaker without ever falling down and covering the heatsink.
Most importantly: the RF whine is gone. If you’re dealing with similar interference in your room, a simple copper fabric shield like this might be the missing piece, especially if you’ve already upgraded cables and still hear noise.
Here's a link to some of the materials I used. The copper fabric worked great wrapped on the inside of my equipment rack too.
If you need help with your productions, mixes, or voice-over projects, feel free to reach out!
Ashton Price
www.MorphProductions.com
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