M2n4-SLi Front panel USB memory speaker noise?

[PNemesis]

Rig:
M2N4-SLi
4GB 1x4 kingston @667
Palit 8800GT 512
SB Audigy SE
3xHDD
PSU Chieftec 550W
etc...

Ok I have weird problem, when I connect memory flash onto front panel USB, and start to transfer something onto flash, I have noise coming out of speakers. Mobo back USB is working properly. Flash is also working properly.
Tried 2 flash memory 2GB one and 256MB one, and I have same result.

So what can be the problem?

 

[Onus]

Could be miserable shielding of connector cables inside your box (the ones going to the front panel). Are your speakers USB-powered? If so, all kinds of activity on other USB ports might get through to your speakers.

 

[PNemesis]

No, they are not USB powered, they are directly connected to Audigy / Altec Lansing 2.1.
It just happens on front panel. Mobo USB on the back are OK.

 

[PNemesis]

I removed Audigy and remained on onboard sound, AC97 realtek. Now I get noise form speakers and headphones (front panel), and it gets noisier when I move mouse.

I used one hand to touch case, and other hand to touch radiator, and I can feel small amount of electricity running through my fingers.
EDIT: House grounding is OK, it exist, and it's not null.

 

[robidigital]

I have the same exact problem. Mine usually happens when I plug my phone into the front usb. I also have my speakers plugged into the same 5.25" bay unit though. It has 3 usb ports, speaker, mic, 5-in-1 flash reader, firewire. It's really annoying!