These kevlar tweeters were used in some Impulse speakers that are popular here and I thought it might interest a few people to know that it's possible to repair the foam surrounds used on these tweeters and keep them operating in close to original condition.
As far as I am aware ALL Focal tweeter latex foam surrounds are in a state of decay and failure. Firstly DO NOT Touch your surrounds to test this theory! The foam degrades into a sticky gooey mass and touching it will immediately degrade it further, pulling it away from the surface and lifting it from the tweeter. I suspect this is why you see so many of these tweeters in a poor state. Dust or a hair sticks and then in removal causes separation.
I've now repaired a pair of T100k and a pair of T120k and audibly this has had a subtle but worthwhile improvement to both pairs in improving the tweeter output.
The T100k is unfortunately much harder to repair than the T120k due to glue ingress in the channels cut in the back of the faceplate that house the coil leads. The T120k has tape covering these channels and so removing the coil leads is much much easier. In other models the voice coil leads exit via the front of the faceplate making the T100k probably the most difficult to repair.
If you are interested in a repairing your tweeters I can highly recommend the kit from Audiofriends. They also have a video that is much better at showing the complete repair than my few photographs can show. I would recommend getting extra brushes so you can do the glueing in several separate attempts.
The repair does require a very steady hand and some guts to pull apart a 'working' set of tweeters but is well worth while. Fully documenting the process at the time is a skill in itself so apologies for the missing steps!
Difference between T90 & a 'doped' Impulse T120, the kelvar weave is much lighter on the T120.
