LEDs cause speaker noise


May 11, 2015
A long time ago I got an LED strip with a controller to put behind the desk, but I rarely use it. When it is turned on it causes my speakers to hum loudly, and when it is just plugged in (not lighting up) it makes a different hum. Only unplugging power from the LEDs helps. I have two sets of speakers connected to my PC, over AUX and displayport. It does not affect my headset though. So it seems it only affects speakers connected to the wall outlet. Plugging any of the speakers into a USB sound card didn't help either. I tried to research it, but my experiences didn't match up with any of what I found. I figured it must be some sort of electrical interference, not sure though. The hum also changes pitch along with the colour.
Any suggestions?

Thank you in advance.

My hardware:
Logitech X-530 5.1 Speakers (AUX)
Logitech Z-313 2.1 Speakers (DisplayPort)
Generic LED strip with controller.
I tried using: MoBo onboard sound, USB soundcard and sound over DisplayPort.
Two possibilities:

  • ■The LED controller is emitting some sort of RF interference, which your speaker cables (unshielded cables are basically big antennas) are picking up and converting into a sound the speakers play back. Usually this can be eliminated by adding RF chokes to both ends of the speaker cable. RF chokes are basically magnets which make it harder to "slosh" the electrons back and forth along the cable. They're weak enough so it won't affect real speaker signals, but strong enough to block RF interference.

    The fact that the headphones don't suffer this problem would suggest this isn't the cause. But it's not guaranteed because different length wires act as different antennas, so the headphone cable just may not be picking up the interference.
    ■The LED controller generating high frequency noise in the power cord, which is being fed back into the power outlet thereby "polluting" the power going to other devices plugged into that outlet. I'll bet the LED controller uses a two-prong plug - no third ground plug? Adding RF chokes to the LED controller's and speaker's power cable is worth a shot, but I doubt it'll work. Isolating the power source of the LED controller and speakers usually does the trick. Try plugging them into outlets on a different household circuit (which go to a different circuit breaker for your house). Or if you've got a battery backkup (UPS) with AVR, try plugging the speakers into that, the LED controller into the wall. Some of the more expensive surge suppressor power strips will also have this functionality.
If either of these fix the problem, it still points to the LED controller being a poorly designed and poorly shielded piece of cr@p that you should probably throw away and replace. If it's an RF issue, it could be causing radio interference at unknown frequency, possibly degrading your WiFi speeds or radio/TV over the air reception. Or interfering with other radio broadcasts (e.g. police who are driving by your house). If it's a power issue, it could slowly be causing damage to other devices you plug into the same outlet, as they have to deal with running on "dirty" power.


May 11, 2015

Sorry i didn't answer quicker. It wasn't the controller itself, it was the 12V powersupply for the leds. It might have been low quality or defective, but just getting a new powersupply with the right specs, solved the problem. But thank you, for answering anyways.
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