I have a 12" bl and and I recently built a new box for it. I noticed some what of a clicking sound coming from the sub. At first I just thought it was something rattling in the back of my car but today I went to check it out and noticed it was coming from the sub. It only seems to do it on the low notes and it doesn't do it every time either. I can't seem to figure out what or why it is making that sound.

is the subwoofah moving 4.7" back and forth when it tick tick ticks? Or only 2"

You're probably smacking the spiders into the top plate...if you haven't already snapped them.

Turn your subsonic filter up.

It was kind of hard to tell but I held a tape measure up to it and it looks like it starts doing it around 2"

I turned it up and that seemed to fix it.

Thanks for the help