Posted 12 December 2012 - 06:41
the interference everybody is talking about is called Electromagnetic Interference also known as Radio Frequency Interference. this could cause issues. but, you mention when an appliance is turned on in the kitchen you have this issue. unless your computer speakers or cables are located near your kitchen, i don't believe this would be your issue as an EMI Field caused by a home appliance wouldn't be large enough to affect other rooms. it is possible for an EMI field to affect an actual circuit but considering only your speakers are experiencing this issue, i doubt this is what is happening.
its possible you may have a bad ground on that circuit. can you run an extension cord from the speakers to a different circuit? then try turning on an appliance you know was causing the issue and test it.
if that doesn't correct your issue, its possible you might have a bad house ground. if that is the case, i would recommend calling in a licensed electrician to test the grounding points in your house. since you are experiencing this issue with multiple appliances, i suspect this is the culprit.