An audio system is disclosed in which offset phenomenon caused by a phase difference between the reproduced audio signals of front speakers and rear speakers is prevented. In the system a plurality of equalizers compensate the frequency characteristics of the output signals of a volume controller. A power amplifier amplifies the power of the output signals. A phase adjusting circuit divides at least one or more sets of the audio signals into a plurality of frequency bands when the audio signals are inputted from a volume controller to the plurality of the equalizers, and adjusts the phase of at least one or more sets of the audio signals among the divided audio signals. Accordingly, phase interferences are prevented between the audio signal sets of the front speakers and the rear speakers, and therefore, the audio signals of the low frequency bands can be boosted in a natural manner.