Hi...Would a layer of 2 in 1 closed cell 1/8" foam over a layer of 6 mil poly be more effective for sound and moisture protection than 2 layers of 6 mil poly under sub floor? I have a concrete slab, and will be blind nailing solid planks to sub floor.

A wholesale wood floor tech in the bus. for 40 yrs. recommended this under the floating sub floor. How do you top pros weigh in on this method?

Thanks