Speakers intermittently making a buzzing sound

[Rationale]

I use Creative GigaWorks T20 speakers.
http://www.newegg.com/Product/Product.aspx?Item=N82E16836116043

I've had them for just under a year. They sometimes make a sort of buzzing/warbling noise for a few seconds, then stop. I only notice it when the speakers are not actually playing any audio, because it's quiet and would be drowned out if the speakers were actually in use.

It's not a big problem, just slightly annoying, but I'd like to know if it's indicative of a problem that could get worse, or what's causing it.

They're connected to an Asus Xonar DG sound card, which I've had for about half a year and appears to be working correctly.
http://www.newegg.com/Product/Product.aspx?Item=N82E16829132020

 

[nostall]

I use Creative GigaWorks T20 speakers.
http://www.newegg.com/Product/Product.aspx?Item=N82E16836116043

I've had them for just under a year. They sometimes make a sort of buzzing/warbling noise for a few seconds, then stop. I only notice it when the speakers are not actually playing any audio, because it's quiet and would be drowned out if the speakers were actually in use.

It's not a big problem, just slightly annoying, but I'd like to know if it's indicative of a problem that could get worse, or what's causing it.

They're connected to an Asus Xonar DG sound card, which I've had for about half a year and appears to be working correctly.
http://www.newegg.com/Product/Product.aspx?Item=N82E16829132020

I could be wrong, but that sounds like interference, possibly from an outside source such as a very highly overpowered radio transmission (such as a CB Radio with a linear amp.) How often does it happen, or more importantly does it happen at the same time of day every time.

 

[Rationale]

It seems to happen randomly, pretty much whenever they happen to be idle. It probably happens for 4-5 seconds every ~15 minutes.

 

[nostall]

Is there a major household appliance nearby? Example: a refrigerator on the other side of the wall by the computer.
Still looking for interference; are they plugged into the same circuit as an appliance? (Other then by visual inspection, the only other way I know of to check this is to turn them on and then throw the breaker switch at the breaker/power box and see if they and something major powers down) I was surprised to find my entire home-office shares current with part of my garage and my outside plugs; found out when I tried a window mount air conditioner - using different plugs in different locations.

 

[Rationale]

There's the PC itself about 6 inches away from the speakers. Other than that, everything is at least a full room away. I will test flipping breakers.

 

[nostall]

If you don't find anything doing the breaker check,then there is a reasonable possibility that the speakers (the small amplifier that they have) are going bad.
Have you Googled your speakers to see if your experience has happened to others?
I have heard nothing bad about the Xonar cards so I would let that be the last of the trouble shooting area, unless some other forum member can input information about this problem.

 

[foadrezek]

I had the same problem, it was my router which was sitting right next to the speakers