I get interferance from my mouse cable, a little from my moniter and lots from my hard drive.
Personaly I like it, once your used to it you can her your PC 'thinking'
I can even use it to detect the tiny drop in frame rate when my uboot is neer a single merchant
I get a hellofa weird interferance sound when I click generate on SHIIIGen. Its like a slow, high pitched wistle that gets lower (like the sound a falling shell makes) and the the same sound 3 times but speeded up very fast.