Jacobsen Finn, Molares Alfonso Rodríguez
Acoustic Technology, Department of Electrical Engineering, Technical University of Denmark, Kgs. Lyngby, Denmark.
J Acoust Soc Am. 2009 Aug;126(2):676-84. doi: 10.1121/1.3158918.
Energy considerations are of enormous practical importance in acoustics. In "energy acoustics," sources of noise are described in terms of the sound power they emit, the underlying assumption being that this property is independent of the particular environment where the sources are placed. However, it is well known that the sound power output of a source emitting a pure tone or a narrow band of noise actually varies significantly with its position in a reverberation room at low frequencies, and even larger variations occur between different rooms. The resulting substantial uncertainty in measurements of sound power as well as in predictions based on knowledge of sound power is one of the fundamental limitations of energy acoustics. The existing theory for this phenomenon is fairly complicated and has only been validated rather indirectly. This paper describes a far simpler theory and demonstrates that it gives predictions in excellent agreement with the established theory. The results are confirmed by experimental results as well as finite element calculations.
能量考量在声学中具有极其重要的实际意义。在“能量声学”中，噪声源是根据其发出的声功率来描述的，基本假设是该特性与声源所处的特定环境无关。然而，众所周知，发出纯音或窄带噪声的声源在低频混响室内的声功率输出实际上会随其位置而显著变化，而且在不同房间之间的变化甚至更大。由此导致的声功率测量以及基于声功率知识的预测中的巨大不确定性是能量声学的基本局限性之一。关于这一现象的现有理论相当复杂，且仅得到了相当间接的验证。本文描述了一种简单得多的理论，并证明它给出的预测与既定理论高度一致。实验结果以及有限元计算证实了这些结果。
