I hate it when people ask for advice, and then do the exact opposite anyway, but this is an exercise of using surplus materials and installing a system on the cheap and cleaning off parts on the shelf. So I built the box out of 3/4” plywood left over from the basement reno. Glued, screwed, and biscuited, then all the internal seams sealed. Hopefully it sounds okay and holds together.

Next up: sanding and cleaning up my rough carpentry, and then adhering some automotive carpet to it. Then onto the wiring component of this project.