Ponencia presentada en el XIX Congreso Internacional de Acústica (ICA2007), Madrid, 2-7 Sep 2007.-- PACS: 43.55.Ti, 43.55.Rg.Acoustic wall backings usually involve damped lightweight plates whose critical frequency locates at high frequencies (≥ 2000 Hz). Additional decoupling is achieved by using mineral wool in the cavity. Theories of Heckl, Sharp, and other authors explain sufficiently well acoustical performances of such linings, within the Heckl’s frequency interval (f0 – fc). They are "proper acoustic materials" as its performances are nearly independent of the lined wall. In Mediterranean countries, Spain noteworthy, where ceramic products are largely used, there is a big interest on developing ceramic plates as efficient acoustic wall linings. This paper presents a phenomenological behaviour of ceramic wall linings showing a clear correlation between acoustic properties and constitutions plus mounting conditions. It is shown that important values of improvement of sound reduction index, ΔR(f), can be got, even outside the Heckl’s frequency interval. Their nearness with optimum profiles regarding reference curves of low an medium critical frequency, is used to explain its high single number rating scores, 20 dB and more. An increasing use in Spanish brick type buildings is envisaged in the immediate future.This work has been granted by the Spanish National Research Program PN 2004, Project: BIA 2004-07 102-CO3-01. Authors also thank to HISPALYT (The Spanish Association of Fabricants of Bricks and Roofs) by the support and facilities concerning materials and mountings of experimental arrangements.Peer reviewed