broken connexion on speaker

[stf]

I'm having an issue with the speaker on my Zero, after making a few tests to see if everything fits in the box the connexion on the negative side on the speaker broke. I'm thinking of soldering it again but the connexion is under some foam / glue. Is that safe to remove this? Or should I just buy a new speaker? Is there an other way to connect that cable (as its the negative side, I'm thinking it could be possible to solder it directly on the back of the speaker....?)