So one of my subs is creating what I can only describe as what sounds like a plastic bag rattling. This happens at lower frequencies. For example, in the song 'Pop The Trunk" by Yelawolf. During the kicks and the higher parts of the bassline there is now rattle but there is during that low note. When I push down on the cone, it moves freely and I hear no scraping at all. The sub doesn't get hot and it seems to be keeping up with the other one.
EDIT: The sound is very quiet and not noticeable until you get right next to it.
Any ideas?
The subs are Sa-12s. The only difference I noticed is on the one that is making the noise, the dust cap looks to be a tad off center.
I tried taking a pic of it but they don't show it very well.
Thanks for reading!