i am building a new house and will have an upstairs 12x12 room. i am a musician and would like to keep most of the sound in the room as not to bother the wife. 1/2 the room will already have r13 insulation. my builder suggested completing the room in r13 and putting r19 in the floor. will this do what i want it to for cheap? also, what types of hot/cold issues will i run into if i do this?

thanks in advance for any help.