The inner core part of the diffuser can be removed from the outer frame for easy installation and cleaning. The back can be equipped with tuyere regulating valve to control and adjust the air volume. Suitable for broadcasting studio, hospital, theatre, classroom, concert hall, library, entertainment hall, theatre lounge, general office, shop, hotel, restaurant, gymnasium and so on. In order to make people in a variety of environments to avoid noise interference and discomfort, in addition to determining the neck wind speed according to the performance table, also need to consider the installation height and installation occasions.