Inter-laboratory variation in sound power levels in qualified reverberant rooms.

Abstract

Reverberant acoustic test facilities can be qualified to determine the sound power levels of broadband and tonal noise sources using the procedures defined in Air‐Conditioning, Heating and Refrigeration Institute (AHRI) Std. 220, “Sound Power Testing Using Reverberant Rooms for HVAC Equipment.” Member companies from AHRI’s Technical Committee on Sound participated in a round robin test program in which tonal noise sources were shipped to, and tested in, a number of qualified reverberant rooms. This report summarizes the results of this effort. The mean and standard deviations of the sound power levels for multiple locations/orientations of the noise sources in each facility and for all facilities are presented. The standard deviations as a function of frequency for these sources were found to be generally less than the values established for broadband sources and therefore less than those allowed for tonal sources. Based on the comparisons of round robin test results, accurate determinations of sound powe...