To economically create a music not attracted with attention by an audience such as background music, without being restricted by copyright and the related.

A sound source device SS accumulates digitally sounds corresponding to musical instruments assigned by program numbers as forms of phonemes, the sounds are read out to get frequencies assigned by a pitch generator PG, and analog audio signals are generated with wave forms corresponding to musical instruments classified by musical instrument kinds indicated by the program numbers from a controller CNT-P, with amplitudes of musical instrument sound volumes based on signals from a controller CNT-V, and with action applied to clear sounds of percussion instruments in particular based on output trigger signals of a sigmonide function generator T in the final layer of the second neural network. Atmosphere constituting music with many elements is generated with very economical constitution free from copyright.