Reducing cavity dependence in helmholtz resonators via compact neck arrays

Conventional Helmholtz resonators are widely used in low-frequency noise control due to their resonant characteristics. However, their resonant frequencies and acoustic impedance are inherently constrained by the cavity, which limits applicability in space-constrained scenarios. This study proposes a sound-pressure regulation strategy to mitigate this cavity dependence by leveraging the coherent coupling effect within a compact neck array. The approach enables adjustment of the system’s acoustic impedance, allowing the absorption peak to shift toward lower frequencies without altering the cavity size. Theoretical analysis, finite element simulations, and experimental measurements consistently demonstrate that, for the same cavity volume, a compact neck array design achieves a greater low-frequency shift compared to both independent-neck configurations and dispersed neck-array arrangements. The design strategy improves the low-frequency absorption performance of Helmholtz resonators and is particularly suitable for noise control in limited-space environments.