ABSTRACT
Any transducer using a diaphragm or membrane to generate sound is essentially a bidirectional radiator, since the air is excited by both sides of the vibrating surface. Since the driver dimensions are typically smaller than the wavelength, sound will diffract around the driver forming an aerodynamic short circuit. The radiation will be similar to that of a dipole. We saw in Chapter 3 that the dipole is a very inefcient radiator. A short-circuited diaphragm needs to make very large excursions, particularly at low frequencies, to generate sufcient sound pressure for home, studio, and cinema sound reproduction. Because of practical limitations, the large excursion is unavoidably associated with large nonlinear distortion.
