Comparisons of measured sound power levels across octave bands gathered from different methods and labs

Abstract

This poster presents results to date from an interlaboratory study, aimed at quantifying the bias and reproducibility of three different sound power measurement methods used in the heating, ventilation, and air-conditioning industry: free field method, diffuse field method, and sound intensity method. The sound power of a certain loudspeaker sound source has been measured in at least 15 testing facilities using the methods generally applied in those facilities. Two test signals are used in the measurements: a broadband signal whose slope decreases −5 dB per octave band, and the same signal with four discrete frequency tones at 58, 120, 300, and 600 Hz. Comparisons of the measured sound power level data, gathered to date, are presented across one-third octave bands. The project continues to collect data from other test facilities so that rigorous findings on the repeatability, reproducibility, laboratory bias, and measurement method biases may be determined, according to ISO 5725. [Work supported by the Ai...