I just bought a pair of used JBL Eon G2 15" speakers. One is great. The other has a rattle in it. I suspect/hope it's something loose inside. The rattle isn't continuous. It occurs mostly at a low/mid range. I'm using them to monitor Vdrums and, when I hit the second highest tom, it rattles. I could send it back and pay shipping but first I'd like to see if it's something simple. I tried to unscrew every screw I could find and get the cabinet open but it still wouldn't budge. I couldn't pry it open the slightest to look in. How do you get them open? Am a missing some hidden screws or tricks? Any suggestion on repair or diagnosis? Thanks.