Look at it this way... if the amp or CD player were on fire and the speaker went silent or started sounding funky, would you still be eyeing up the speaker as the culprit? I think not.

That's a little drastic but consider, when amps and other electronic devices go south, there are usually no visible signs to identify which it is. You gotta do a little detective work.

...just switch the speaker leads on the back of the amp (R > L and L > R) and see if the problem travels to the other speaker. If it does, then the problem is not the speaker.