Evaluation of performers’ preferences for stage acoustics in concert halls

Abstract

ABSTRACT The correlations between the stage acoustics parameters of concert halls and the performers’ preferences are derived through the evaluation by performers on actual stages for stage acoustic design reflecting the preferences of the performer. Furthermore, the elements of stage acoustics influencing the performance of performers are investigated, and a stage acoustic design method for optimizing these factors is proposed. To evaluate performers’ preferences of stage acoustics, we should understand the expressions of stage acoustics used by performers. It is necessary to investigate which expressions describe the physical stage acoustic elements from the professional performers’ position for the practical improvement of stage acoustics from the standpoint of performers. It is known that vocabulary expressing sound is closely related to acoustic evaluation. However, research on the acoustic evaluation vocabulary for domestic performers has been insufficient until recently, and the stage acoustic evaluation expressions for ensemble have not been sufficiently developed. We need a proper sound evaluation vocabulary suitable for domestic circumstances. Thus, for future evaluation of stage acoustics, a research was conducted with professional performers to develop expressive vocabulary that can be used by the performers. Stage support (ST) proposed by Gade is most frequently used for stage acoustic evaluation owing to its simplicity of measurement and clarity of definition, and also has a close correlation with the subjective evaluation of performers. Therefore, subjective listening evaluations were conducted on an actual stage focusing on stage acoustic factors for solo and ensemble including duet, trio, and quartet. As an indicator for quantitative evaluation of the ensemble, an ensemble model formula for stage acoustics was derived to evaluate the preference factors and the degree of ensemble based on the subjective evaluation result of a trio ensemble. Trio ensemble was set as the representative group for analyzing the experimental results of the duet, trio, and quartet ensemble. As architectural elements related to the stage of a concert hall, the shape and material of the acoustic reflectors surrounding the stage or the orchestra shell play a crucial role in the overall stage acoustics. However, there are different criteria such as density for selecting the stage acoustic reflectors that constitute the stage, and research is needed on them. Therefore, this study focuses on the design of the acoustic reflector itself, which constitutes the stage and orchestra shell among the stage design elements. Furthermore, the effects of the acoustic reflector on the sound absorption characteristics and the stage acoustics are researched. In addition, various methods for adjusting the reverberation are being considered in the acoustic design of the concert hall for acoustic design by natural acoustics as well as by electronic acoustic system. Therefore, subjective responses of the performers were investigated according to the reverberant sound pressure level (Lrev [dB]) and the reverberant sound pressure for each frequency band of reverberation. Throughout this study, the overall preference of the performers was considered at the center of the stage, while the position of the duo was varied according to the types of ensemble instruments. The increase in both STEarly and STLate increased the preference of soloists; STEarly increased the preference of trio and quartet, and STLate increased the preference of solo and duet. As ST decreased, the preference of the ensemble increased, and the increase in blending and bass ratio (BR) increased the preference of the soloist. As an architectural element, the effect of density change on stage reflector was investigated. As a result, sound pressure level (SPL), Reverberation time (RT), BR, and ST were increased as the density of acoustic reflector increased, and the stage acoustic of the concert hall for the performer could be improved by changing the density of the acoustic reflector. In addition, the performer's preference for reverberant sound pressure level and tone during real-time play through the electronic acoustic system were evaluated, and it was found that there is a certain preference range for reverberant sound pressure level and tone.