skiletic

I have a Promedia 4.1 system. On my head speaker (front right), for quite some time now, when I'm playing at moderate volume the speaker emits a loud crackling noise like a bad static. Simply by tapping the speaker, it goes away, but always returns. I looked in the unit and didn't see any obvious wire problems; the static appears to be coming from the top part of the speaker. Any assistance or suggestions for my next step greatly appreciated.