I have my speaker in one of my belt pouches, this particular model had a boom mic with it that fitted over my head, I just have the wires under my neck seal and my vest and plug into the box at the belt pouch, not saying that is the best idea, just the way I did it.
A lot of Stormtrooper fan sites have speaker boxes, so you could try that, or try the trading stations here and on the mandalorian Mercs site.