oz

I had the problem bigwill refers to with one of my 60's. Play something that has the imperfect sound .. .try to pinpoint, by placing your ear close to each individual driver, which driver is causing the noise . . .then remove the driver and check on the connectors at the back of the speaker. Sometimes they can be just a bit loose. I tightened the connectors for the midrange driver on one of my 60's and voila. . .the problem was solved.