I ended up applying Roxul (brand name) which is a mineral wool used for firestopping & soundproofing btwn the joists - it now comes in batts similiar to the pink stuff

Next applied MLV (mass loaded vinyl) 1/8" thick HEAVY stuff and difficult to work with overhead (see pic) THEN used grid system & Acoustical tiles - Not an easy application

Depends what you are isolating - ?Foot fall on wood floors above - that is probably the most difficult - I still hear foot fall

We did it now for kiddies - isolate the noise - later perhaps a real home theatre

layers of sheetrock - of varying thickness is another proven soundproofer - homosote (basically what these ceiling tiles are) is another -

Try over on the remodeling forum - you'll find threads there and also on home theatre type acoustical forums

It does get confusing & adds $$$ up - any conduit for sound must be properly treated or you will continue w/same prob.

I put a wood exterior door from finish/utility side of basement w/a sweep on the bottom
walls btwn the 2 sides may need to have some application as well

good luck