Modelling of sound fields in enclosed spaces with absorbent room surfaces Part II. Absorptive panels

This is the second part of a report on the modelling of sound fields in enclosed spaces with absorbent room surfaces. Both Sabine and Millington absorption coefficients are used to further investigate which approach produces the most accurate predictions. Classical formulae and geometric acoustic models, previously detailed, were used to predict the reverberation time in a test room with highly absorbent room surfaces. In addition the test room was configured with a partially absorptive surface. This configuration has previously only been predicted inaccurately. It was shown that the Millington formula predicted more accurately than either the Sabine or the Eyring formulae in the configurations of the room investigated. Verification of the previous results were confirmed when two of the computer models gave consistently more accurate predictions using Millington absorption coefficients than Sabine absorption coefficients.