A double-leaf partition in engineering structures has been widely applied for its advantages, that is, in terms of its mechanical\nstrength as well as its lightweight property. In noise control, the double-leaf also serves as an effective noise barrier. Unfortunately\nat lowfrequency, the sound transmission loss reduces significantly due to the coupling between the panels and the air between them.\nThis paper studies the effect of a microperforated panel (MPP) inserted inside a double-leaf partition on the sound transmission\nloss performance of the system. The MPP insertion is proposed to provide a hygienic double-leaf noise insulator replacing the\nclassical abrasive porous materials between the panels. It is found that the transmission loss improves at the troublesome mass-airmass\nresonant frequency if the MPP is located closer to the solid panel. The mathematical model is derived for normal incidence\nof acoustic loading.
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