I've had these speakers for 3 years, and all of a sudden out of nowhere, the right speaker just starts buzzing. It sounds like a fly or bee is in my room. If I adjust the volume up, the buzzing becomes louder. I've unplugged and plugged wires back in and nothing seems to help. It happened twice today. The first time is lasted for about 10 seconds and then it stopped or flew away. But now it seems to be permanent!