I just got a 408 today. It has the original Eminence drivers in it from '78. The bottom two speakers work fine (and sound real nice, too). The top two speakers have problems, though. They sound like there is metal vibrating against metal somewhere. I took the speakers out to inspect them and the inside of the cab. Everything looks fine except for one of the bad speakers has a dented dust cap that has an inch long split from the cone. The other bad speaker has no visible damage. I tried the 9 volt battery test and all four speakers moved in unison. Any more than that is beyond my expertise. I'd very much prefer repairing the speakers to replacing them, if possible. Any advice or recommendations? Anyone know of a good speaker tech in the RI/MA area?