PURPOSE: To reduce the disorder of an output sound pressure frequency characteristic by providing a subcabinet having baffle provided at least to one side of a main cabinet so that the surface of the baffle will be the same as that of the main cabinet in plane level.

CONSTITUTION: The point different from the conventional one is that a subcabinet 5 is provided, for instance, at one side in the horizontal direction of a main cabinet 2a, so that the surface of a baffle will be the same as that of the main cabinet 2a in plane level. In such constitution, an acoustic space backward of a signal speaker 1 can prevent the odd-dimensional standing wave from generation. Since distances of diffracted sounds 11 and 12 up to a sound receiving point A are different in sound wave propagation as for the sound wave which is radiated forward from the speaker 1, the interference of a direct sound 10 and the diffracted sounds 11 and 12 is dispersed due to the different in the sound wave propagation distance of the sound wave transmission of the direct sound 10 and the diffracted sounds 11 and 12, and the disorder of an output sound pressure frequency characteristic is reduced.