Reverberation Chamber

A reverberation chamber is a laboratory room designed to create a highly diffuse sound field with long reverberation times, typically 5–15 seconds. It has hard, non-parallel walls with rotating or fixed diffusing elements to ensure random incidence of sound on test specimens. Reverberation chambers are used for measuring random-incidence absorption coefficients (ISO 354:2003), sound power levels (ISO 3741), and sound insulation between rooms (as part of ISO 10140 test suites). The room must meet minimum volume requirements (typically >150 m³ per ISO 354) and demonstrate sufficiently diffuse conditions. Absorption coefficient measurements in a reverberation chamber are the basis for NRC, SAA, and αw ratings. Because the sound field is diffuse, results represent averaged performance across all angles of incidence. Reverberation chambers are expensive to build and operate, and only specialized acoustic laboratories maintain them.