Soundproofing is a term often incorrectly used to describe acoustic panels and baffles. These products have a NRC Rating (noise reduction coefficient) that indicates how effective they are at reducing reverberation (echo). True soundproofing blocks sound, rather than absorbing echo. Products intended to block sound will have a STC Rating (sound transmission class) not a NRC Rating. STC Ratings are commonly found on windows, doors and wall assemblies.