An analysis of design conditions for a phase-inverter speaker system with a drone cone

In this paper useful design conditions for a phase-inverter speaker system with a drone cone, which realize a flat response, are given for the first time by applying the network synthesis theory to the sound-pressure transfer function of this speaker system. The design conditions are obtained in relation to the sound-pressure zero below the reproducing region for the cases of the general Butterworth and the general Chebyshev rational function characteristics, and also obtained in relation to the amount of ripple of the sound-pressure frequency response in the reproducing frequency region for the case of the general Chebyshev rational function characteristic. The effects of equivalent resistance of the box due to the absorbing material on the design conditions are also considered. The calculated sound-pressure frequency response based on the design conditions obtained agrees fairly well with the measured response. Comparison of the sound-pressure frequency response of this speaker system with those of the closed box and the bass-reflex system is also given.