Acoustic Barrier for Low‐Frequency Broadband Noise Insulation and Ventilation

It is a fact that achieving excellent ventilation and excellent sound insulation is usually not possible simultaneously. Furthermore, attaining effective ventilation and sound insulation across a broad frequency range represents a significant challenge. In this paper, a sub‐wavelength‐thick (≈ λ /8) acoustic barrier based on a microperforated panel (MPP) and a Helmholtz resonator (HR) is designed for broadband acoustic isolation and ventilation. Unlike traditional separate MPP‐HR composite structures, this design adopts an integrated “single MPP + double serially connected HR” layout, which enables continuous dual‐band sound insulation. As demonstrated by simulations, the barrier can effectively block more than 90% of the incident energy within the frequency ranges of 680–1024 and 1030–2190 Hz (30% wider than the single low‐frequency band of existing HR + MPP structures), while maintaining 16% of the ventilation area ratio. It has been determined through analysis of the characteristic modes of the structure that the HR structure produces the first acoustic isolation band, while the MPP structure primarily acts in the second acoustic isolation band. Experimental verification confirmed the stability of sound transmission loss (STL) values within the range of 13–40 dB, with minimal fluctuations, when the frequency was in the 654–1600 Hz range (surpassing the 18 dB STL of 3D‐printed ventilated metamaterials). Additionally, an analysis was conducted to determine the impact of MPP and HR structural parameters on the sound insulation effect. The design exhibits considerable potential for implementation in applications necessitating a combination of ventilation and sound insulation, while its uncomplicated structure renders it eminently practical.