In 2004 a system of small reverberant chambers was started to operate in Moscow, the system allows to measure the sound absorbing characteristics of the fragments of the constructions with the degrees of the sound absorbing up to 80 dB at the guaranteed absence of the indirect ways of the noise transfer. At this, the High -Level Chamber (HLC) is also used to measure the reverberant coefficients of the sound absorbing in accordance with the GOST 26417-85 "Construction Sound Absorbing Materials. The method of testing in the reverberant chamber".
To measure the sound absorbing characteristics of the samples of the construction materials (first of all, the normal coefficient of sound absorbing) the company uses three different acoustic interferometric analyzers (Kundt's pipes): underfrequency one with the scope of measurements from 50 Hz; midfrequency one (125 - 2000 Hz) and the high-frequency (1600 - 8000 Hz).
The dynamic response of the resilient construction materials is measured with help of vibrant exciters: the small one and the big one. These measurements are made in accordance with the standard of GOST R 53378-2009 "Acoustic materials applied to the floating floors of the residential buildings. Method of defining the dynamic rigidity".
For the comparison tests for decreasing the level of the impact noise with different resilient materials the reference screed located within the system of the small reverberant chambers is used. The source of the impact noise is a standard "stamping" machine Look-Line.