Quick question. My mom had some horrible speakers and I replaced with some baby advents that I picked up at a garage sale for $20.00. She loved em. Now she says that one of the speakers has a buzz to it. Any ideas on how to fix, other than to replace the cheap speakers? What could be causing the buzz? I would love to buy her some polk's, but I can't force myself to part with one of my pair and I cannot afford to buy her a used pair. If I can't salvage the advent's any recomendations on decent used speakers?