Sound power of musical instruments measured with sound intensity in a practice room

The data on sound power of musical instruments published by various authors demonstrate considerable spread. In most studies, sound pressure was used for the determination of sound power. In the present study sound power was determined from sound intensity. The discrete point method with 10 measurement points on a hemisphere and 80 to 300 points on rectangular surfaces was used for the evaluation of sound power. The measurements were carried out for three instruments: the bassoon, the upright piano, and the snare drum. The instruments were played by professional musicians in a typical practice room. The music samples played on the bassoon and on the piano were scales and excerpts of music. The samples played on the snare drum were rhythmic sequences and tremolo sounds. The results demonstrate that sound intensity is a reliable method for the estimation of sound power level of musical instruments played in a small practice room. The paper discusses the influence of the measurement method, the test room acoustics, the playing technique, the choice of music sample, and the player’s stability on the uncertainty of measurement. [This work was supported by Grant No. 7-T07B-043-10 from the State Committee for Scientific Research.]