The asym­met­ric, tiled room in the base­ment of ETI provides an ex­tremely long re­ver­ber­a­tion can be used for vari­ous ap­plic­a­tions. The ini­tial ap­plic­a­tion since found­a­tion of the in­sti­tu­te was the re­ver­ber­a­tion of mu­sic­al sound in a most nat­ur­al way. As an acous­tic­ally most dif­fuse sound field the meas­ure­ments of acous­tic ab­sorp­tion of damp­ing ma­ter­i­als and sound power of sources are part of edu­ca­tion and re­search.