Improvement of sound insulation for double leaf partitions at low frequencies

虽然双叶隔板的总重量小于单叶隔板的重量，但它在中高频段提供了有效的隔音效果。但由于质-气-质共振，低频区的隔声性能往往不如单叶。在本研究中，为了提高隔声性能，在双叶隔板的腔内安装了亥姆霍兹谐振器。安装谐振器后，在谐振器的谐振频率f0处，隔声性能明显提高，而在高于f0的频率处，隔声性能出现了新的下降。然而，适当控制谐振器的吸声性能，可以防止在安装谐振器后，隔声性能在f0以上下降。因此，谐振器的使用能够有效地提高双叶隔板的隔声性能。

A double leaf partition provides effective sound insulation at middle and high frequencies, although the total weight of the partition is less than the weight of a single leaf. However, the sound insulation in the low-frequency region tends to show lower performance than that of the single leaf because of mass-air-mass resonance. In this research, to improve the sound insulation, Helmholtz resonators were installed in the cavity of the double leaf partitions. After installing the resonators, the sound insulation increased considerably at resonance frequency f0 of resonators, while a new dip was detected on the sound insulation at frequencies higher than f0. However, the appropriate control of sound absorbing performance of the resonators prevented the sound insulation above f0 from declining after installing resonators. Consequently, the usage of resonators was able to improve efficiently the sound insulation of the double leaf partitions.