Boiler fan mufflers are designed based on the actual test data of noise sources from various industrial fans, determining the required noise reduction levels across specific frequency ranges for the main design of acoustic absorbers and fluid channels. Additionally, narrow rectangular channels with large acoustic material facings are used to enhance absorption. Furthermore, when the fan noise source operates at high noise levels, its frequency spectrum often consists of more than one type, and the noise reduction requirements vary for different frequency bands. To address this, the series of ventilation管道 mufflers and exhaust fan mufflers are of impedance acoustic flow type, utilizing resistive structures for high and mid-frequency noise absorption and antiresonant structures for mid and low-frequency noise reduction. High and low-frequency acoustic absorption zones are also incorporated into the resistive channels to maximize the noise reduction frequency range, achieving effective noise reduction and sound absorption.