Sound proofing floor


I am at the point that I don't need to modify or purchase anything else. But I am considering sound proofing the floor for the sake of my neighbors which know that I will lower the volume when they ask. I am considering raising the floor and making that raised floor decoupled from the room and insulated.
Any ideas?
pedrillo
I concur entirely with getting consul from an acoustical engineer, I needed to hear that from members, thank you.
Please inform us of the acoustical engineers advice. It will be interesting to look at the cost benefit ratio. Without going into specifics your idea of a 2nd floor islolated from the 1st is 'very' effective and I think you will find this confirmed by the engineer. (My father is an engineer)
Zargon, thanks for the info on the green glue. I'm doing some renovating and soundproofing for a suite and I'll definitely benefit from your input.