The absolute most common work a vintage speaker might need is refoaming. How do you know if your speaker needs to be refoamed? Well, this problem’s pretty easy to diagnose. It looks like this:
The foam surround has dried out and is disintegrating. Often if the surround needs replacement there will be chunks missing or the whole surround will simply be gone.
If the speaker has sat unused for a very long time, the surround might still be completely intact, but poke it with a finger and it will crumble.
Running speakers with damaged or missing surrounds will eventually destroy the voice coil. It will also sound like garbage.
Refoaming is simply the process of removing the remains of the old surround, cleaning the cone and frame, and glueing in a new one. At our shop, we also coat the new surround with latex to prevent the problem from recurring in the future.
Hit us up if your speakers are in need of love! -sam