A flat plate audio transducer. A front panel and a back panel are connected via a frame. One or more electromagnetic actuators are mounted between the two panels. Voice coils are used as the actuators in some embodiments. Stiffening braces are preferably run between groups of actuators to prevent unwanted resonance phenomena. In some embodiments an actuator array moves both the front and back panels. In other embodiments only one panel is moved.

A speaker (10) includes a radiation surface (15). The radiation surface (15) has a first region (15a), a second region (15b), and a third region (15c) between the first region (15a) and the second region (15b). When an axis passing through the third region (15c) and extending away from the radiation surface (15) is defined as a reference axis (10X), the speaker (10) forms a first wavefront (16a) propagating from the first region so as to approach the reference axis (10X) and a second wavefront (16b) propagating from the second region (15b) so as to approach the reference axis (10X).

A flat plate audio transducer. A front panel and a back panel are connected via a frame. One or more electromagnetic actuators are mounted between the two panels. Voice coils are used as the actuators in some embodiments. Stiffening braces are preferably run between groups of actuators to prevent unwanted resonance phenomena. In some embodiments an actuator array moves both the front and back panels. In other embodiments only one panel is moved.

A sound reducing system (500) includes at least one sound reducing speaker for radiating a sound wave for sound reduction. The at least one sound reducing speaker includes a piezoelectric speaker (10). The piezoelectric speaker (10) includes a piezoelectric film (35), a fixing face (17) in contact with a support supporting the piezoelectric speaker (35), and a film holding portion (55) disposed between the piezoelectric film (35) and the fixing face (17). (i) The film holding portion (55) includes a pressure-sensitive adhesive layer and the fixing face (17) is formed of a surface of the pressure-sensitive adhesive layer and/or (ii) the film holding portion (55) includes a porous body layer.

A system for controlling noise in a fenestration assembly (e.g., a window) includes a fenestration assembly with at least one glazing and a frame. The at least one glazing has a surface. At least one sensor is coupled to the at least one glazing and is configured to generate noise detection signals. An actuator is positioned on the surface of the at least one glazing and has a plurality of regions. A controller is coupled to the sensor and the actuator and is configured to control each of the regions of the actuator to generate a different frequency based on the noise detection signals. Alternatively, each of the regions may be controlled to generate a frequency with a different phase shift based on the noise detection signals.

A speaker (10) includes a radiation surface (15). The radiation surface (15) has a first region (15a), a second region (15b), and a third region (15c) between the first region (15a) and the second region (15b). When an axis passing through the third region (15c) and extending away from the radiation surface (15) is defined as a reference axis (10X), the speaker (10) forms a first wavefront (16a) propagating from the first region so as to approach the reference axis (10X) and a second wavefront (16b) propagating from the second region (15b) so as to approach the reference axis (10X).