Here is a corner. They are pretty much all the same. Bad.
Get in there with some 80 grit to rough up the wood. The autobody filler adheres well. Here is an early stage after using a rasp on the still soft filler.
Here is the method used to rasp. The front part of the rasp MUST BE flat against the body of the speaker, or you will end up with uneven and rounded edges.
Repeat the filler and rasping until you have a nice edge and corner, then spray with some primer, like this. It take many repetitions to get it right:
If you are covering with Duratex you are done. If you are painting, you will need to get out the spot putty to fill the rough parts. Here is what it looks like with 1 coat of Duratex. There will be two.
I have already painted and restored the horn. I have the front wedge redone. I have the front face about 75% done. All I need it the bottom and back edges, and I will post some completed pics.