Abstract: Offshore wind energy is an important means of achieving the national strategy for carbon peak and carbon neutrality. However, the pile foundations used for offshore wind turbines can generate significant underwater noise during pile driving, which can have a detrimental effect on the survival and reproduction of marine organisms. It is therefore important to control the underwater noise generated by pile driving. This paper confirms the feasibility of using polystyrene foam and rubber plastic sponge to reduce underwater noise caused by pile driving through small-scale tests. The two materials are used as components in the Hydro Sound Dampers to investigate their noise attenuation effect and optimal configuration method for effective and low-cost investigation and control of underwater noise. The Hydro Sound Dampers exhibit excellent noise reduction properties when using the two materials. The effect of component parameters, such as layout density and material thickness, on the noise attenuation effect is analyzed in the time and frequency domains. The study compares the sources and mechanisms of the difference in the effective frequency band of the underwater noise spectrum of steel and aluminum piles. This provides a new research idea for the economical and effective study of the underwater noise mitigation method and device of pile driving in the laboratory.