I own a pair of R16 polk audio speakers. One of them is producing a cracking/distortion sound when it is in use. The sound is not over powering but more annoying. The sound is at all volumes and it is there when I play music or watching a movie. I have tried new speaker cord and I have also swapped the speaker to a different channel. No matter where it is in the house and what ever channel that speaker is on the cracking is there in the one speaker. Is it a blown speaker? Please someone help!!!