In recent years, the active noise control methods are more attractive in reducing unwanted noise. Salient features of active control methods over passive control methods drive more attention to active noise control systems for reduction of low frequency noise. The main work in this thesis is active noise reduction of sound in the ventilation systems. Two different kinds of active noise control methods were introduced to reduce the unwanted noise and the implementations were successful. In conclusion, choose the best method based on the best attenuation achievement using different setups of the duc