The boundary element method was used to calculate the sound pressure levels at the two ears of an artificial head when a sound source was located in different directions and distances in the near field (within 1 m). Total loudness was then calculated by using a binaural loudness model. Results showed that, in the near field, total loudness does not always increase monotonically as the source distance decreases. As distance decreased (for bands with center frequencies above 2 kHz), generally loudness first decreased and then increased (creating a local minimum); and when the distance became very small, the loudness generally began to decrease again (loudness had a local maximum). The external surface model of the artificial head was explored computationally. Calculations confirmed that the local minimum and maximum were caused by scattering from the shoulders. The effect of the width of the shoulders on near-field loudness was also determined. Finally, psychoacoustic experiments were conducted on four subjects. Results confirmed the presence of a local minimum and maximum and supported the idea that scattering from the shoulders was the main cause.

中文翻译：

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响度随距离的近场变化

当声源位于近场（1 m以内）的方向和距离不同时，使用边界元法计算人造头的两只耳朵的声压级。然后，使用双耳响度模型计算总响度。结果表明，在近场中，总响度并不总是随着声源距离的减小而单调增加。随着距离的减小（对于中心频率高于2 kHz的频段），通常响度首先减小，然后增大（产生局部最小值）。当距离变得非常小时，响度通常又开始下降（响度具有局部最大值）。通过计算探索了人造头的外表面模型。计算结果证实，局部最大值和最小值是由肩膀散落引起的。还确定了肩膀的宽度对近场响度的影响。最后，对四个对象进行了心理声学实验。结果证实了局部最小值和最大值的存在，并支持了从肩膀散射是主要原因的观点。