Patent ID: 7430912

Claim:
A method predicting random incidence sound absorption and unknown sound absorbing sample, the method comprising: a) measuring a first angular specific sound absorption spectrum of a first sound absorbing sample, the angular specific sound absorption spectrum being determined a sound wave incident on a surface of the first sound absorbing sample with a predetermined angle of incidence greater than zero degrees from a plane parallel to the surface of the first surface wherein the first sound absorbing sample has a predetermined random incidence sound absorption spectrum; b) determining a first weighting factor that provides a fit of the angle specific sound absorption spectrum of the first sound absorbing sample to the predetermined random sound absorption spectrum; c) measuring a second angular specific sound absorption spectrum of a second sound absorbing sample at the predetermined angle of incidence; and d) using the first weighting factor from step c) to determine the random specific sound absorption spectrum from the angle absorption spectrum of the second sound absorbing sample.