I'm confused because when you use Skype, then you're using the mic.
Are you saying the person hears you OK when you use the mic on Skype?
If so, there's nothing wrong with the mic. The problem lies within whatever application you're using -- albeit the mic setting or the application has some issues.
Wait! Are you saying it's actually your speakers that are the problem..or is it your mic? I'm confused about where you are reporting the problem.