Trying to return the thread to real information....
Understand, funksoulrubber, that real isolation, the kind that will allow your neighbors really to not notice that you are making a whole crapload of sound, require carefull attention to details. Bad seals on the door or bad caulking or a penetrating duct or outlet box or even a screw-through on resillient channel can undo a lot of other expensive work.
Ok, that being said, lets look at your specific problem. First of all what you are describing seems sort of like mass loaded vinyl but not quite. I am leary about their claims. Be leary about miracle soundproofing claims from a material that is not heavy. Besides I am guessing this stuff is pricey.
Usually the biggest problem with converting a basement is headroom. If you are lucky your basement has a full 8 feet of headroom but many do not, Adding a whole extra set of joists, at least six inches deep plus sheathing is going to give you a rather claustrophobic space.
Now, lets go to the basics. What you want is two massive and decoupled leaves with a cushioned air space in between. You already have your first leaf, the floor above. but how do you add mass to it? You could add it to the floor above, like putting mass loaded vinyl under the carpet, or if the floor above is untouchable direct screw a layer of gypsum board directly to the underfloor between the studs, caulking the edges. sure the joists themselves will represent a flanking path, but they have some mass too.
Next comes the airspace, which you have between the joists already. You just have to cushion it so standing waves do not get set up in the cavity. Fluffy insulation found at home improvement stores is sufficient for this. Fill it nice and solid.
Now comes the lower, decoupled leaf. What I would suggest is two layers of gypsum board screwed to hat channel on isolation clips, such as RISC-1 or ISOMAX. The mounting clips are expensive, but the gypsum board is cheap. But watch the details: caulking, penetration, connections to walls, etc. And of course this is just the ceiling. No soundproofing is better than its weakest element.
hey thats a good idea big d. i think thats homisode what your talking about? ive heard of that working well someware before. i bet its fairly cheap aswell? i will look further into it. Thanks a bunch!
As far as my questions are concerned, they were NOT for me. They were for YOU. Go to a doctor and tell him your gut hurts, but you only want him to tell you whats wrong and don't ask questions 