In reply to:
(1) A layer of R19 insulation in the cavities between the joists; beneath that, a resilient channel; beneath that, one layer of sheetrock.
Now I may be off base here - been a long time since I was an insulator's helper, but we used to use R8 as sound damping material. (realize now that you're probably using engineered floor joists which have a deeper floor cavity, so this would make some sense!) RC, which has taken over from stiff metal furring bar works very well at minimizing vibration transfer (found
this with a quick Google)
In reply to:
(2) One layer of R30 insulation; beneath that, one layer of homasote; beneath that, one layer of sheetrock. No RC in this option.
No channel, but homosote, which multi-purpose arenas still use as flooring material, both for it's sound damping and to protect ice/court surfaces. Homosote is really more to "soften" hard surfaces from my experience to reduce reflected sound waves, and not so much to be used to deaden and stop transfer of vibration.
I have no hard suggestion for you, but I'm kind of curious as to why they chose what they did for materials in these options.
Bren R.
