Apologies, this is not a specific Sonar issue, but I hope someone has had this and maybe has solved it:
I use Neuman KH 120 monitors and I have recently added a Yamaha H8 subwoofer.
Ever since, whenever I move the (usb cable) mouse, there is a soft buzzing sound.
All connections are over high-quality Neutrik/Contrik balanced XLR cables,
with TRS jacks on the interface side. Cables all check out OK on my Behringer (sorry) cable tester.
My interface is the Cakewalk/Edirol UA25EX, Win7 Home 64bit, Acer Aspire laptop with i7 processor.
Remove the sub and connect the Neumanns direct, no more buzz.
Ummm.