Glue down the Serena Mat® to the original subfloor which could be a slab or wood frame. Then glue down a layer of 3/4″ Tongue and Groove OSB. OSB resists warping better than plywood.
Take care if the floor has valleys and crowns as the plywood may not lay flat. This may require a concrete Tapcon screw to be installed and later removed when the glue dries. You can weight with a bag of sand or heavy object as well.
Soundproofing Floor Solutions