bending wave loudspeaker
All known loudspeakers generate the sound pressure via a diaphragm, which radiates the sound
into the free space. It is different with the bending wave technique. In this technique, a flat, large diaphragm is excited by one or two electrodynamic exciters. In the bending wave transducer, the diaphragm, which is about the size of 60 cm x 80 cm, is not moved vertically, but is deformed. This creates transverse waves on the flat, thin membrane that propagate uniformly in all directions on the plane of the membrane. The propagation results in an air vibration that is perceived as an acoustic signal. The design of a bending wave loudspeaker is relatively complex because the diaphragm material has a significant influence and because various resonance points for different frequencies must be formed on the flat, stiffened diaphragm. The area where the diaphragm is attached is particularly critical. Here, a wide variety of materials such as aluminum, foam rubber, and others are used to broaden the frequency range so that it can encompass all octaves of the human hearing range. Unlike the directional sound radiation of traditional loudspeakers, bending wave transducers radiate at an angle of 360°. The bending wave process can be compared to the waves caused by a stone thrown into water. Such waves also spread evenly over the surface of the water. If the reviews of the experts regarding the sound quality of the bending wave transducers are to be believed, then the sound experience is better than that of other speakers.- The principle of the bending wave transducer is also applied in reverse to touchscreens for position determination. This method is also known as Dispersive Signal Technology( DST).
