Since a few years I have had a pair of Creative T20 loudspeakers for my computers. They are great because it is just a 2.0 system, and they sound excellent. But I have had problems with humming noise and worse for a long while. Today I read on the creative forums that others have had similar problems. So, I opened my right loudspeaker (the one with all the electronics) and drowned the potentiometers in universal oil (CRC/5-56). It worked – now they seem all fine!