Acoustic systems with passive emitter

Passive emitter

— speakers in which at least some of the speakers have a passive radiator.

Such a radiator is actually a diffuser, devoid of a coil and a magnet; outwardly, it looks like an ordinary speaker, but it does not produce sound on its own, but only oscillates under the influence of the sound of active emitters. Such a device helps to improve the power and saturation of low frequencies. A similar effect can be achieved using a phase inverter or a labyrinth (see the relevant paragraphs), however, a passive radiator still gives a slightly different effect. In addition, in this case, there is no tube in the design, which could create some noise due to air movement (which is important for phase inverters); and compared to acoustic labyrinths, passive radiators are noticeably simpler and cheaper. On the other hand, an additional diffuser significantly affects the dimensions of the case (primarily the height and/or width).