Laboratory measurements provide more accurate sound insulation results than calculation methods for multi-layered elements, especially for those with local materials. In this study, the sound insulation values of traditional Turkish hollow brick masonry cavity walls are measured in test rooms, and the results are discussed. Horizontally perforated hollow brick walls with two different thicknesses are used to build double brick walls with varying cavity depths and mineral wool thicknesses. The aim of this study is to discover the sound insulation characteristics of traditional Turkish cavity brick wall elements and to discuss the factors, especially cavity depth and filling thickness, that affect the sound insulation values of these walls. (C) 2015 Institute of Noise Control Engineering.