In a reproducing apparatus of the present invention, an input audio signal is divided into bands and an envelope value of each band is measured. Based on a change of the envelope value, a predetermined sound source is superimposed. Further, according to the envelope value of a reproduced audio signal, a tempo of reproduced music is detected and animation representation is changed in synchronism with the detected tempo. Further, a rhythm box is reproduced in synchronism with the detected tempo and a sound field is automatically selected corresponding to the detected tempo to perform synthesization.