Addressing the environmental challenge of noise control in substations, a novel type of acoustic metamaterial was proposed as a sound insulation component. The component, which consisted of an elastic film, a mass ring, and a Helmholtz cavity, was structured with a dual-resonance configuration. It was investigated for its sound insulation performance and vibration modes within the frequency range of 10 to 1 000 Hz using COMSOL simulation software with a solid-acoustic coupled finite element model method. The results show that the metamaterial effectively blocks noise, especially in the low-frequency range, overcoming the limitations of traditional sound insulation materials in controlling low-frequency noise. The sound transmission loss of the component in the frequency range of 35 to 1 000 Hz was tested and verified through impedance tube sound insulation performance experiments. It is concluded that this new type of acoustic metamaterial offers an effective solution for noise control in substations.