What's causing a noise in my Apogee Stage Speaker?

I have a noise, which sounds like crinkling tinfoil, coming from the bass driver on one of my Apogee Stage speakers. Can anyone tell me how to get rid of this noise? I'm not certain but I have a feeling that I can remove the back plate and tighten or loosen the screw for the bass driver and this may correct the problem. Can anyone confirm for me that the problem may be fixed by doing this? Thanks