okay so when i went to band practice today.....my 1x15 cabinet was making a weird rattling noise as if something was on top of it or leaning against it, that would rattle.. but there was nothing! i have a GK 800rb amp and it's bi-amped so the 1x15 was getting most of the bass, so i sent everything to the 4x10 speaker: the rattling went away but naturally it sounded really dumb. We took off the cover of my cab and nothing was visably wrong with the speaker. Question: what the heck is wrong with it????? somebody help me!!!! the last time i used the set up was when we played a show earlier that week...i had it pretty loud. i haven't messed up the speaker have I??? i don't know very much about technical stuff so......whatever that's worth. side question: every time i turn off my amp, i get that annoying popping sound.....is that normal? if not, how can i stop it?