In this study, a self-made phononic crystal was designed and used in a zig-zag path pipeline. It was combined with a cavity to form a circuit-like RLC resonance structure. The theoretical characteristic frequency was simulated using COMSOL software to stabilize the sound pressure in the center of the cavity and achieve a magnification effect. Experiments were conducted in an anechoic room, where the sound pressure was converted into an electrical signal by an amplifying circuit. Our experiment’s variables were the frequency of the sound source, the distance between the device, and the size of the cavity . The results showed that our self-made phononic crystal was able to successfully amplify the voltage by about 2.6 times. The advantages include the small size, the simple geometry, and can be expanded to a polycrystalline structure. In the future, it can be combined with piezoelectric materials to create an environmentally friendly device that has both power generation and noise reduction functions.