I was thinking putting one or more of those small transducer, vertically, inside the emiiter walls.
If the blade needs to be sanded in order to get flatter, in that place, that shouldn't be a drama
I just thought of something more.
15 days ago I watched Sabertalk 8 on Spacewindu youtube channel and during this program they talked about the possibility to push saber sound to another device via Bluetooth.
That's quite an interresting idea. But not an easy one to achieve for several reasons.
But if we want to just have sound to a bigger external speaker, I just thought that a FM Radio emitter would make just as good without difficulties. So I also ordered a tiny module to add to my future hilts.