KEF 103.4 mid-range driver problem (B160 SP1278)

Hello everyone,

I just bought a pair of old KEF 103.4 speakers from the 90s. Unfortunately 1 of the speaker sounds completely muffled. I thought the ferrofluid of the tweeter had to be replaced but the problem seems to be the mid range driver. The driver is a b160 sp1278 and it seems that the membrane is somewhat stuck. if I apply pressure on the membrane it does not move freely. It feels like there is a lot of resistance (the other speaker’s membrane is much more flexible and the speaker sounds fine). It also seems there there is a damage. I attach a video where I try to visualise the issue

I would swap out the driver but I am not able to find any. Does anyone have a clue if there is a way to fix this issue? Any suggestion is highly appreciated. I really don’t want the speaker to end up in the landfill so I would like to repair it.

Many thanks!

Alberto
 
Welcome to the forum!

It is possible that the mid's voice coil has been overheated and has been warped out of shape so that it no longer move freely in the magnetic gap.

Re-coning would probably be the only answer other than a driver replacement.

EDIT: There are videos on YouTube showing how to replace damaged voice coils.
 
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