A Model for the prediction of Sound Levels within a Symphonic Orchestra based on measured Sound Strength

Members and directors of symphonic orchestras are concerned about the noise levels musicians are exposed to and their ease of playing ensemble. The results of many research has shown that the noise levels within an orchestra can be high. Also, research has shown that the sound level will vary between different musicians playing different instruments and musical pieces or musicians being positioned differently on various stages. Aspects of influence on sound levels can be musically based: the piece and its interpretation by the orchestra; or acoustically: the impact of the stage and hall acoustics. However, the contribution of each instrument and each acoustical aspect on the total sound level cannot be determined from sound level measurements. Therefore, a sound level prediction model is proposed based on the sound strength G and the early to late reflection ratio LQ7-40. For every combination of two orchestra instruments, the direct, early reflected and late reflected sound energy transfer is calculated. In the direct sound transfer, the directivity and sound power of the instrument and the attenuation of the orchestra are taken into account. The early and late reflected sound energy is based on the sound power and on measured values of G and LQ7-40. From the individual sound level contributions, the total sound level and balance between different instruments and different acoustical aspects can be calculated. First results show that the model gives insight in the sound levels within a symphonic orchestra from a health as well as a musical point of view