Panton Lilyan, Holloway Damien, Cabrera Densil
School of Engineering and ICT, University of Tasmania, Hobart, Tasmania, Australia.
Faculty of Architecture, Design and Planning, University of Sydney, Sydney, New South Wales, Australia.
J Acoust Soc Am. 2017 Apr;141(4):2461. doi: 10.1121/1.4979119.
Early reflections are known to be important to musicians performing on stage, but acoustic measurements are usually made on empty stages. This work investigates how a chamber orchestra setup on stage affects early reflections from the stage enclosure. A boundary element method (BEM) model of a chamber orchestra is validated against full scale measurements with seated and standing subjects in an anechoic chamber and against auditorium measurements, demonstrating that the BEM simulation gives realistic results. Using the validated BEM model, an investigation of how a chamber orchestra attenuates and scatters both the direct sound and the first-order reflections is presented for two different sized "shoe-box" stage enclosures. The first-order reflections from the stage are investigated individually: at and above the 250 Hz band, horizontal reflections from stage walls are attenuated to varying degrees, while the ceiling reflection is relatively unaffected. Considering the overall effect of the chamber orchestra on the direct sound and first-order reflections, differences of 2-5 dB occur in the 1000 Hz octave band when the ceiling reflection is excluded (slightly reduced when including the unobstructed ceiling reflection). A tilted side wall case showed the orchestra has a reduced effect with a small elevation of the lateral reflections.
早期反射对于在舞台上表演的音乐家来说很重要，但声学测量通常是在空舞台上进行的。这项工作研究了舞台上室内管弦乐队的设置如何影响来自舞台围合结构的早期反射。通过在消声室中对坐着和站着的受试者进行全尺寸测量以及与礼堂测量结果进行对比，验证了一个室内管弦乐队的边界元法（BEM）模型，这表明BEM模拟给出了逼真的结果。使用经过验证的BEM模型，针对两种不同尺寸的“鞋盒式”舞台围合结构，研究了室内管弦乐队如何衰减和散射直达声和一阶反射。对来自舞台的一阶反射进行了单独研究：在250Hz及以上频段，舞台墙壁的水平反射会有不同程度的衰减，而天花板反射相对不受影响。考虑到室内管弦乐队对直达声和一阶反射的总体影响，当排除天花板反射时，在1000Hz倍频程频段会出现2 - 5dB的差异（当包括无遮挡的天花板反射时略有减小）。一个倾斜侧壁的案例表明，管弦乐队对侧向反射的提升较小，其影响也会降低。
