Sound problems with my computer speakers. Help needed.

About one and a half years ago I bought a Logitech Z-560 speaker system, along with the rest of my computer (I built it). Since then, I have had no problems until about a month ago. Whenever I try to adjust the volume while the speaker control center is on, a loud crackling kind of noise comes from the front left speaker. After a few seconds of slowly adjusting the volume up and down, the crackling becomes a little quieter and occurs less often. If I am not adjusting the volume, there is no crackling and all of the speakers sound fine. After reading a bit online, it seems that this kind of problem is usually attributed to the sound card (I have a Sound Blaster Audigy 2.) To test this, I switched the speakers over to the onboard sound card on my Abit IC7-G motherboard. I turned the computer back on, adjusted the volume, and there was the same loud crackling coming out of the left speaker. I also know it is not the speaker because I have plugged in headphones into the control center and I still get crackling out of the left channel of the headphones. My last guess is the subwoofer, but how would it be affecting my headphones? The headphones don’t use the subwoofer, do they? Any suggestions on what could be wrong are appreciated.

Just a WAG, but you could have a grounding problem. Try unplugging the speakers from the wall, waiting a second and plugging them back in. This happened to me a few days ago, and unplugging/replugging fixed it.

This sounds to me like dirty contacts on the potentiometer in the volume control. The issue can’t be either the sound card or the speakers for the reasons you give, which leaves the connections between them, and the volume pot would be the prime suspect.

Dirty potentiometers are pretty common, and not difficult to remedy. With the sound completely off, turn the volume knob through its complete range of motion rapidly numerous times, say, for 15 seconds or so. This might be sufficient on its own to solve the problem. If possible, you could also open the case on the control centre and clean the volume pot with contact cleaner.

Thanks, but unfortunately, neither suggestion worked, and there doesn’t seem to be a way to open the control center. I also realized that it couldn’t be the subwoofer, because the wires go from the computer to the control center to the sub, so if it was the sub I wouldn’t be getting any problems with my headphones. So it seems that the problem can only be in the control center or the wires going to it.

Well, that it’s crackling makes it almost certainly bad contacts somewhere. Ground issues typically manifest themselves as hums or buzzes. I still think it’s got to be the volume potentiometer. The only other likely candidate would be the contacts on the jacks for the left speaker, but that’s ruled out by the fact that the left channel crackles with headphones, too. And just the fact that it crackles most when you fiddle with the volume knob is suggestive, too. If aggressive wiggling of the volume knob doesn’t help, then the only solutions would be getting inside so you could spray contact cleaner into the pot, or changing the pot altogether. There’s almost certainly a way to open the control case, but I certainly can’t help you with that from here. You might try contacting Logitech’s product support.