近场声全息重建参数对隔声测量精度的影响

Influence of Near-Field Acoustic Holography Reconstruction Parameters on the Accuracy of Sound Insulation Measurement

等效源法近场声全息可以开展建筑构件隔声测量的工作。采用近场声全息测量构件隔声量时,重建参数对声场重建结果影响显著。基于对等效源法近场声全息隔声测量理论的分析,利用传声器阵列测得构件表面的复声压信号,通过声场重建得到构件的隔声量和表面法向声强分布。为进一步探究重建参数对等效源法近场声全息隔声测量精度的影响,通过控制变量法在隔声室开展以传统声压法为对比的建筑构件隔声测量实验。结果表明:当等效源面位置从-2 cm变化至-5 cm时,表面法向声强的重建平均误差值由3.9 dB增大至5.6 dB,隔声量的重建平均误差值由5.2 dB增大至6.9 dB,测量误差随等效源面距离而增大,因此等效源面宜靠近声源面;当全息测量面距离为4、8和16 cm时,表面法向声强的重建平均误差值分别为0.6、1.9和5.5 dB,隔声量的重建平均误差值分别为0.9、1.4和4.6 dB,测量误差随全息测量面距离而增大,因此建议全息测量面距离保持在8 cm之内;当等效源点数目与全息面测点数目一致时,与传统声压法差异仅为0.84 dB,当二者数目不一致时,隔声量和表面法向声强平均误差值均增大至4.6~6.8 dB。通过对重建参数进行优选可以有效提高构件隔声测量精度,对实验室测量建筑构件隔声性能与方法有重要借鉴意义,同时在隔声测量技术的实际运用中有较高的参考价值。

Equivalent source method near-field acoustic holography can be applied in sound insulation measurement of the building components.When near-field acoustic holography is used to measure the sound insulation volume of components,the reconstruction parameters significantly affect the acoustic field reconstruction results.Based on the theoretical analysis of near-field holographic acoustic insulation measurement by equivalent source method,the com⁃pound sound pressure signal of the surface of the component was measured by the microphone array,and the sound in⁃sulation volume and surface normal sound intensity distribution of the component were obtained through the acoustic field reconstruction.To further investigate the influence of reconstruction parameters on the accuracy of equivalent source method near-field acoustic holography,experiments on sound insulation measurement of building components were carried out in the sound insulation room by the control variable method in comparison with the traditional sound pressure method.The results show that when the position of the equivalent source surface changes from−2 cm to−5 cm,the average error value of the reconstruction of the surface normal sound intensity increases from 3.9 dB to 5.6 dB,and the average error value of the reconstruction of the sound insulation volume increases from 5.2 dB to 6.9 dB,and the measurement error increases with the distance of the equivalent source surface,so it is suitable for the equivalent sur⁃face to be close to the sound source surface.When the holographic measurement surface distance is 4,8,and 16 cm,the average error values of the reconstruction of the surface normal sound intensity are 0.6,1.9,and 5.5 dB,and the average error values of the reconstruction of the sound insulation volume are 0.9,1.4,and 4.6 dB,respectively.The measurement errors increase with the holographic measurement surface distance,so it is recommended to keep the ho⁃lographic measurement surface distance within 8 cm.When the number of equivalent source points is consistent with the number of measuring points on the holographic surface,the difference with the traditional sound pressure method is only 0.84 dB.When the number of equivalent source points is inconsistent with the number of measuring points on the holographic surface,the average error values of the reconstruction of the sound insulation volume and surface nor⁃mal sound intensity distribution increase to 4.6~6.8 dB.By optimizing the reconstruction parameters,the accuracy of component sound insulation measurement can be effectively improved.It has important reference significance for laboratory measurement of sound insulation performance and methods of building components and has high reference value in the practical application of sound insulation measurement technology.