Variable Acoustic Technology for Rooms

The present invention relates to a system with variable acoustic properties configured to cover boundaries (11) of a space, such as walls or ceilings of a room, the system comprising a plurality of modules or units (2) with variable acoustic properties having a front face (4) provided with openings (6) through which sound energy can enter an inner region (3) of the module or unit (2), and where one or more of the modules or units (2) comprises a sound absorbing device (12; 38, 39) in acoustic communication with the openings (6) in the front face (4), which openings (6) can be closed, such that sound energy cannot enter the inner region (3) and opened, such that sound energy can enter the inner region (3), where the front face (4), including the openings (6) herein, of a plurality of said modules or units (2) are covered by a covering sheet (8) that extends as an unbroken surface over the plurality of modules (2), and where the covering sheet (8) is configured such that it makes it possible for sound energy to enter the interior region (3) through the covering sheet (8) and the openings (6), when the openings (6) are in an open state. The invention further relates to modules for use in the above described system and to a method for altering the reverberation time of a room, especially atlow frequencies.