The small holes in the perforated gypsum board form a resonance cavity with the gypsum board itself and the surface layer of the original building structure. After the sound interacts with the perforated gypsum board, the air column at the round hole produces a strong resonance, and the air molecules interact with the gypsum board hole. The wall rubs violently, which consumes a large amount of sound energy and absorbs sound. This is the basic principle of "Helmholtz resonance" sound absorption for perforated plasterboard. The sound absorption of perforated plasterboard has a certain selectivity to the sound frequency, and the sound absorption frequency characteristic curve is in the shape of a mountain. When the sound frequency is close to the resonance frequency, the sound absorption coefficient is large; when the sound frequency is far away from the resonance frequency, the sound absorption coefficient is small . If the paper perforated gypsum board is covered with a layer of mulberry paper or thin sound-absorbing felt, the frictional resistance of air molecules at resonance will increase, and the sound absorption performance of each frequency will be significantly improved. This is why people often use perforated paper. The plasterboard is covered with a layer of mulberry paper or thin sound-absorbing felt to increase the sound absorption. The main factors affecting the sound absorption performance of the paper perforated gypsum board are the perforation rate and the size of the back cavity. The perforation hole diameter and the thickness of the gypsum board have little effect on the sound absorption performance. When the perforation rate gradually increases from 2% to 15%, the surface area occupied by the holes increases, and the probability of air molecules entering the resonance cavity to participate in resonance increases, and the sound absorption capacity increases. If sound absorbing materials are placed in the back cavity , The sound absorption is stronger. The perforation rate will affect the resonance frequency. As the perforation rate increases, the resonance frequency will shift to high frequency. The offset is proportional to the root of the perforation rate. As the perforation rate increases, the "mountain" of the sound absorption frequency characteristic curve will move to the right (high frequency), and the overall shape of the "mountain" tends to rise, and the average sound absorption coefficient increases. Increasing the perforation rate can improve the sound absorption performance, but due to the limitation of the strength of the gypsum board, the perforation rate is generally in the range of 2%-15%.