We investigate theoretically and experimentally the absorption of a Helmholtz resonator (HR) array, an aluminum device operated in water. The HR array's period is 2 mm. The operating frequency range is ∼0.2-0.7 MHz. We observed two transmission dips in both experimental and theoretical spectra. These dips are dominated by different resonance orders in the HR. The resonance behaviors are investigated with steady-fields simulation and can be represented by spring-mass models. This allows us to reduce the device's footprint significantly.