Selection of Sound Absorp- tion Coefficients of Acoustically Effective Materials in Calculating Time-Variable Noise in a Room

Reverberation is one of the main processes that determines noise in industrial premises with pulsed sound sources. Its study uses data on the sound absorption coefficients of fences, including acoustical lining used to reduce the pulse noise. It is known that the sound absorption coefficient of effective acoustical lining can vary significantly within the octave frequency bands. Therefore, it is recommended to use arithmetic mean octave sound absorption coefficients according to regulatory documents, otherwise, it can lead to significant errors in the assessment of reverberation processes occurring in rooms. Purpose : Using computer modeling of reverberation processes in rooms, to measure the sound absorption coefficient of effective sound-absorbing materials, ensuring the calculation accuracy in octave frequency bands of time-variable noise in a room. Research findings : Based on the proposed computer technique, it is found that in the case of significant changes in the sound absorption coefficient in the octave frequency band, the attenuation of the octave sound level is determined by the rate of sound decrease in the third-octave frequency band with a minimum average sound absorption coefficient. This coefficient should be taken into account when studying reverberation processes in rooms with acoustical lining.