METHOD OF DETERMINING SOUND ABSORPTION COEFFICIENTS OF MATERIALS Russian patent published in 2015 - IPC G01N29/00 

FIELD: physics.

SUBSTANCE: method includes measuring reference analogue signals using first and second microphones of an acoustic interferometer, analogue-to-digital conversion thereof, calculating a transfer function through continuous wavelet transformation of each of the measured reference signals, calculating reflection coefficients and sound absorption coefficients, presenting the calculation results in graphical form in the form of a curve of sound absorption coefficients versus frequency or geometric mean frequencies of 1/n octave bands, where n is an integer. The reference used is a deterministic analogue signal with duration of not less than 13 s with an exponentially rising frequency in the range of 100-400 Hz.

EFFECT: high accuracy of determining sound absorption coefficients of materials in the low-frequency range.

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