[RFI] RFI from PC speakers

[Andy]

Taking a wild stab here ...

>  A
> quick test of a clamp-on ferrite on the USB cable, then wrapping 10 or
> so turns of the cable around a bigger toroid did not make a dent in
> it.

Clamp-on ferrites affect common-mode noise only.  If there is a switching
regulator that draws power off the USB lines while adding crap to it
(between power and gnd), it won't be affected by the filter because it isn't
common-mode.

My guess though is that the speaker leads might be the antenna.

Andy