Low-frequency and broadband noise reductions have always been a major industrial concern, as they pose a significant challenge. Although acoustic metamaterials are garnering attention in this field, they cannot simultaneously block low-frequency and broadband noise. Thus, this study developed a synergetic soundproofing acoustic metamaterial (SSAM) comprising a membrane and locally resonant structure (LRS) to realize low-frequency and broadband sound insulation. The SSAM suppresses structure-borne noise by utilizing LRS-induced anti-resonance for low-frequency sound insulation and membrane-induced anti-resonance for broadband sound insulation. The soundproofing mechanism of the proposed design was clarified through the dynamic effective density estimated using two impedance models (apparent and transfer impedances), and its sound insulation performance was validated through sound transmission loss simulations. The experimental sound pressure level results indicate that plate- and enclosure-type SSAMs can provide excellent low-frequency and broadband sound insulation. In the future, SSAMs will serve as a reference for the development of materials with noise-reduction capabilities for soundproofing applications, such as home appliances, vehicles, machinery products, and acoustic walls.

低频和宽带降噪一直是一个主要的工业问题，因为它们构成了重大挑战。尽管声学超材料在该领域备受关注，但它们不能同时阻挡低频和宽带噪声。因此，本研究开发了一种由膜和局部共振结构（LRS）组成的协同隔音声学超材料（SSAM），以实现低频和宽带隔音。SSAM 通过利用 LRS 引起的反共振进行低频隔音和膜引起的反共振进行宽带隔音来抑制结构噪声。通过使用两个阻抗模型（视在阻抗和传输阻抗）估算的动态有效密度，阐明了所提出设计的隔音机制，并通过声音传输损失模拟验证其隔音性能。实验声压级结果表明，板式和外壳式 SSAM 可以提供出色的低频和宽带隔音效果。未来，SSAMs将作为开发具有降噪能力的隔音材料的参考，如家电、车辆、机械产品、隔音墙等。