Speakers are quieter than normal.

So I have a set of Bose Companion speakers for my computer. They sound great for me but I have noticed that they have recently started to be more quiet than they were before. My volume is 100% in both League and windows sound settings so I'm not too sure what it could be. I also checked the cables and everything seemed fine. I got them about a year ago. Is it because they are just old now? Any advice would be great.