My cabinets are mostly beyond restoration so I need to rebuild but hopefully improve some things. There is no batting on one side and top of the enclosure. Should there be? Should there be more or different damping material? What should I replace the particle board back and bottoms with? Plywood, mdf or use particle board for some reason. The baffles are ok so I'll reuse them. Should I install internal bracing? I like the size of and looks of the cabinets so I don't want to change dimensions. Anything else I should do? Thanks