Some power data are very useful in connection with preventive noise control and loudspeaker applications. However, such data, i.e. octave or third octave power spectra, are still rare in data sheets on noise producing equipment and loudspeakers. The explanation of the missing sound power data is undoubtedly that sound power measurements are rather time-consuming if traditional measuring methods are used. The system described here reduces the measuring time considerably and the measurement and recording of a complete sound power spectrum is carried out automatically. The essential parts of the system are a traversing microphone, a reference sound source, and a special computer. The reference sound source contains 13 loudspeaker units. Its characteristics are high power output, even power response and low directivity. The special computer uses analog as well as digital techniques. The measuring and recording time for a complete 24 third-octave power spectrum is 17 minutes and the results obtained with the system conform to the standards ISO 3741 and 3742.
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