Sound attenuation at a ceramic tile floor can be very complicated, particularly in a condominium. Most local building codes and Federal regualtions stipulate minimum requirements for sound control in multifamily properties (condominiums). The main sound problem with ceramic tile (a hard surface) is going to be impact generated or structure-borne noise. There is no single component in the floor system that controls how much noise will be transmitted to the unit below. The flooring, subflooring, structural members (wood joist, concrete slab etc.) and the ceiling system work as a system to attenuate noise. My recommendation is to first check with your association to see if they have original construction drawings that identify how ceramic tile was to be installed so as to meet noise control requirements. There should be a floor system detail with ceramic tile that identifies an IIC rating of at least 45. Second, the Tile Council of America (TCA) is a national asociation that represents the ceramic tile industry and they publish specifications for ceramic tile installation regarding noise control. The only product (that I am aware of) that they recommend for noise control is a membrane underlayment caled "Ditra", which is manufactured by Schluter Systems. Check with a local ceramic tile dealer for more information regarding the TCA.