2.1 Speaker Setup Buzz

[Brainiac777]

Hello, I currently own the Harman Kardon SoundSticks III and the speakers create this annoying buzz when my computer turns off. My setup goes like this:

 

Computer Rear Audio Port (Asus Sabertooth Z97) -> 3.5mm Audio Cable (1.5m) -> 3.5 Audio Extention Cable (3.5m) -> Subwoofer -> Speakers

 

What I've tested so far:

~ Speakers & subwoofer on desk with:

> computer on [No Buzz]

> computer off/sleep [buzz]

> audio cable unplugged from computer [buzz]

> iPod [No Buzz] (regardless of PC state)

> power from outlet [buzz]

> power from power bar [buzz]

> only device with power [buzz] (everything else is unplugged)

> audio cable 60cm from computer power cord [buzz]

 

~ Speakers and subwoofer isolated:

> with no device [No Buzz]

> with only one audio cable attached to computer [No Buzz] 

 

Anytime my iPod touch is plugged into the setup, no buzz is heard. Everytime the end of the audio cable is touched to metal or me, the buzz can be heard. Turning up the volume of the speakers when the computer is off increases the noise of the buzz. Everytime I hold the audio cable, the buzz increases in intensity. It might be a ground loop, I'm not sure. The extension cable may be the cause of the buzz since it's long and prone to interference (it's cheap). I'm tempted to go buy either a high quality extension cable or use one long cable for the entire setup. Another detail to note is that the subwoofer is powered by a power brick with no ground plug (it's two pronged). The buzz sounds exactly like a hair cutter

 Thank you.

[EmoRarity]

Sounds like a grounding issue, nothing to really to worry about. Best you can do is power them off or not sweat it. 

[peaking duck]

yeah sounds like a grounding issue.

i have these speakers for tv duties. never heard a buzz. theyre never off, too.

[Brainiac777]

Well, the power switch is difficult for me to reach since the subwoofer is in a shelve. Would it be fine to turn down the volume on the speaker to lower the buzz sound? And doesn't the ground loop harm the equipment?

[EmoRarity]

Well, the power switch is difficult for me to reach since it the subwoofer is in a shelve. Would it be fine to turn down the volume on the speaker to lower the buzz sound? And doesn't the ground loop harm the equipment?

Not really, because its still grounding, its just grounding poorly. I guess you could try lowering the volume, might not work though.

[peaking duck]

i just checked my set. they're two pronged as well with a H/K branded brick. Australian Power

 

give the power connector (it looks like a PS/2 - Svideo connector on mine) a good inspection and clean.

 

i know how you feel. my old Logitech Z5500 speakers used to buzz.

[Brainiac777]

Is there anyway to remove the ground loop? Even with all of my devices unplugged, the subwoofer still buzzes. 

[EmoRarity]

You need the ground loop, and you can not fix it, it os the way it is.

[Brainiac777]

You need the ground loop, and you can not fix it, it os the way it is.

Well, dammit, thanks for the help!