I bought the Hartke Kickback 15 about 2 months ago. Well the last gig I played, I noticed a bit of a rattle coming from the amp. Upon further inspection, I narrowed it down to the speaker. When I play my P-Bass no matter the volume, the rattle is noticeable when playing by myself (on the E string), but when I play live, I cannot notice the rattle. I'm sure the rattle is there, but when I'm playing with my band it is too loud to hear. When I play with my Ibanez SR370E, I don't notice a rattle. I even took the speaker out and checked inside the cab. There was no loose debris or anything like that in the cab. I did play the amp on low volumes with the speaker in my hand (just plucked the E string on my p bass) and I could hear the rattle coming from the speaker. I checked around the cone and the speaker for any tears and didn't see any. I ordered through Sweetwater so they are sending a new one, but I have no clue why it is doing that. It's annoying.