Binaural sound exposure by the direct sound of the own musical instrument

The amount of sound exposure of musicians within a symphonic orchestra is dependent on a large number of aspects. Among these aspects are the many different musical instruments and the impact of room acoustics by the reflected sound. However, it is impossible to obtain separately the contribution of each different aspect from the individually measured sound exposure. Therefor a sound level prediction model was proposed based on measured directivity and sound power of musical instruments and measured STearly,d and STlate,d (Early and Late Support parameter) over various distances. As part of this model, the sound level at the ears caused by the direct sound of the own musical instrument is estimated using the directivity and sound power measured in the free field at a distance of more than 2 m combined with the distance and angle between the musician’s ears and its own musical instrument. To validate this method, binaural sound levels have been measured in an anechoic room while playing the flute, trumpet, trombone and violin. Also, a reference sound level measured in front of the musician at 2 m distance was used to calibrate the model. It was found that the model can predict the binaural sound level by the direct sound of the own musical instrument within 1 dB(A) accuracy; also interaural level differences have been measured up to 7 dB(A). However, estimating the average distance and angle between the acoustical centre of the musical instrument and the individual ears is not always straightforward.