Driver damage - 06/12/03 02:28 PM
Owning m50's and m22's I was happy to pick up a pair of Michaura m55's on ebay to use as rear surounds. When I set them up on top of my m50's to test them, there was an ugly buzzing coming from the bottom driver in one of the speakers. Not having a warranty to consider I grabbed a screwdriver and pulled out the buzzing driver and set it down on its massive magnet structure for a further listen. Indeed the the driver had a grinding buzz coming from it. I also noticed that the basket/cone structure was not sitting flat relative to the magnet structure. Thinking I would contact axiom to get areplacement for the damaged driver I began testing its mechanical action. As I moved the cone back towards the magnet/voicecoil I could feel a physical binding. There appears to be a paper covered flat coil spring that positions the driver cone in a nuetral position and one wind of the spring seemed to be binding against another accounting for the buzzing I was hearing. Feeling I had little to loose I took the driver to my workshop and placed it basket down on my cushiond workbench. With a bubble level I identified the high side of the misaligned magnet to basket structure. I then took a clamp and applied presure until the bubble read level. Removing the driver from the clamp setup the face of the driver and the back of the magnet were now parallel plains and the binding problem was gone. I hooked the diver back up and the speaker now sounds fine. My guess is that rough handling by the postal service jarred the magnet structure out of alighnment causing the problem. I could not tell what the method of attachment was for the magnet structure to the speaker basket--welded/soldered/adhesive/rivets etc. I would be interested in any comments by axiom or others.