When you want to add soundproofing to your ceiling there are two things to consider. Footstep type noise and talking type noise. Airborne noise is soundproofing against talking and TV etc. When you soundproof a ceiling to deal with airborne noise it wont automatically reduce walking around noise unless you include for that in the design. If it is ceiling soundproofing purely for airborne noise then generally adding mass will help but the results will be better if you add isolated mass by using a soundproofing system which includes something like resilient bars. Ceiling soundproofing is usually something that has to be done from beneath if you do not have access to the floor above but the results are always better if you can treat both the floor and the ceiling.