Beating sounds and attenuation sounds generated by first original sound generators (100) corresponding to elements of a conventional drum set are received by augmented microphones. A sound modulator (26) is used for modulating tones of the electronic sounds from the augmented microphones without any digital conversion. A reproducer (34) is used for reproducing the output sounds from the sound modulator (26). Because the processes of digitally converting, transferring signals by optical couplers, and selecting recorded sounds for reproducing are eliminated, the reproduced sounds can represent subtle techniques of the performer by directly using the original sounds generated when the first original sound generators (100) are beaten.