Passive radiators have been built in closed box ever sinceit was invented, this design not only extends its low frequency capability but also remain its own high quality sound. Meanwhile, this innovative combination of active speaker and passive radiator design produces can easily eliminatethe sound of air flow.

      Based on empirical evidence, we can conclude that the easiest way of getting passive radiator is to remove the magnetic system from the active speaker, as well as to make necessary adjustment to match the fo of the passive radiator, so that we are able to receive the quality low frequency.

      Except the traditional way of passive radiator design, there are also flat board and curved surface of design. However, those are involved with T/S parameter of active driver, passive radiator’s compliance and passive radiator’s symmetry, which we will not discuss further here.

      One speaker can be matched with one or multiple passive radiators. The required surface area of the passive radiator would rely on the T/S parameters data provided from active driver, in common, the surface area of the passive radiator is supposed to be larger than the active speaker. However, the result may be varied, engineer will have their own test solution after each trial run.