High pitched noise (in intervals) from Logitech Z313 speakers

Surzilla

Prominent
Jul 28, 2017
2
0
510
I got a speaker system a few weeks ago, Logitech Z313, and whenever I use them on my PC they sometimes make a high pitched static noise. They could be quiet for a minute and then it comes up again for like 5-20 seconds. The static noise starts suddenly and gets louder until it reaches a point where it goes quiet again. If I turn the speaker's volume wheel up, the sound gets louder. I've also noticed it's louder when in-game. The speaker system has a port where you can plug your headset in so you don't always have to switch and when I plug my headset in there, it also has this background static noise, which the headset normally doesn't have (when plugged directly in the PC). It's really frustrating. Can someone help identify the source of the problem? Thanks!
 
Solution
Since the headset doesn't experience the sound when plugged directly to the PC, the noise is probably not being generated by the PC itself. It's probably* an external noise source, and your speaker wires are acting as an antenna and picking it up.

Try adding an RF choke to the speaker wire. It's just a magnet that wraps around the speaker wire (ideally one just before the speaker, one just before the plug that goes into the computer). You may have seen these on laptop AC adapters and monitor cables. They basically add some resistance to the electrons inside the wire, making it harder for external RF noise to move the electrons back and forth along the wire. Like adding baffles to a bathtub to make it harder for your kids to slosh...
Since the headset doesn't experience the sound when plugged directly to the PC, the noise is probably not being generated by the PC itself. It's probably* an external noise source, and your speaker wires are acting as an antenna and picking it up.

Try adding an RF choke to the speaker wire. It's just a magnet that wraps around the speaker wire (ideally one just before the speaker, one just before the plug that goes into the computer). You may have seen these on laptop AC adapters and monitor cables. They basically add some resistance to the electrons inside the wire, making it harder for external RF noise to move the electrons back and forth along the wire. Like adding baffles to a bathtub to make it harder for your kids to slosh water back and forth in it. The signal from the PC has enough power behind it to overcome the magnets, but the weak RF noise does not.

https://www.amazon.com/stardrift-10-Pack-Diameter-Ferrite-Suppressor/dp/B015RAZTIA

For instant gratification, you can try wrapping the speaker wire in aluminum foil. That should create a Faraday cage insulating the wire from outside RF noise. The RF chokes are a lot more attractive though, so are the preferred long-term solution.

* The electrical behavior of your speakers are different from your headset. So there's a small chance that the noise is in fact coming from the computer. It's just that the headset either doesn't cause it or doesn't pick it up, whereas the speakers do. So the RF chokes are not 100% guaranteed to fix the problem.
 
Solution

Surzilla

Prominent
Jul 28, 2017
2
0
510


Thank you! I'll try aluminum foil first and see if that helps.
 
May 12, 2018
1
0
10
I had a high pitched speaker sound from my logitech speakers that suddenly occurred after unplugging them and plugging them back in after moving my desktop pc. I put the jacks in alternative sockets but that did nothing. It went when I plugged the usd connector into a different usb port so it was the pc connection that was causing the noise.
I just re-read your original post though and it's probably not helpful for your issue.