Failing bass amp speaker diagnosis and repair

[grantlaw]

Hi all,

My Behringer Ultrabass BX1200 bass amplifier speaker is producing a breathy, fluttery buzz at particular frequencies -- even at lower volumes. I've sent the signal to another speaker, which operated normally, so I do not believe the issue is with the amp. The noise *sounds* like either the foam seal along the edge or the dust cap may be pulling loose and flapping against the speaker cone, but finger contact on those regions does not eliminate the noise. I would prefer not to replace the speaker, and am capable of making repairs, but I'm not having any luck pinpointing the cause of the noise. Could this sound be caused by major problems with the coil? Something that I probably do not want to mess with?

Thanks,

- Grant

[jjk2007]

Sounds like the driver is toast.

[grantlaw]

Thanks for the response. Do you know of a good way to confirm that a driver is toast?

[gregoire1]

I had a 10 inch speaker do this. It had an audible fuzz sound. I thought it was the surround, but couldn't see anything wrong. It ended up being a warped voice coil. It had over-heated, and was rubbing against the magnet. You can tell if this is your problem by pressing gently against the cone with your hand. If you feel any resistance at all, (scratchy-ness), your voice coil may be warped, or something is touching the back of your speaker like a wire, or foam. Good luck.