Surround Speaker "crackles"

Okay, I am not a speaker expert, so maybe someone can point me in the right direction. Last night, while watching Saving Private Ryan on DTS DVD, one of my rear surround speakers (Boston Acoustics CR6) had a pretty consistent "crackle" to it. This happened mostly during scenes containing lots of low frequency sounds, like rumbles, explosions, etc. I opened up the speaker but couldn't find any visible damage.

Is this indicative of a tear or other physical damage, or could it be perhaps a wire or something internal to the speaker making contact with the bass cone? Any suggestions?

I swapped the rear speakers left-channel to right-channel, and it is definitely isolated to the speaker, not the speaker wiring or the receiver.

Thanks for any help you can give!

 

Thanks for your help, Wayne! I'll give it a shot.