I'm sure this could be for any speaker, but anyway. I've got a chance to buy an Aguilar 112 for $175. It's new but the tag says it has a "loose magnet" and you can hear it bump around when you turn the cab. I'm guessing you'd just have to tighten the magnet to the frame of the speaker to get it right - is that about it? Is it a good deal? Am I getting in over my head?