To solve the problems wherein the voice tone, over an acoustic apparatus, cannot be adjusted readily by one's utterance as one's utterance over the acoustic apparatus is heard differently from that perceived directly, and ample effect, of pseudo-experience where as though another person's voice is being uttered, cannot be obtained, because one's voice modulated and/or converted and one's utterance perceived directly result in being perceived at the same time by a voice changer, or the like.

The apparatus lowers one's own voice which is directly perceived by detecting one's voice that is to be perceived directly, generating sound waves that have phase reverse to that of the voice, and transmitting it, and generates one's modulated or converted voice and allows one to hear the it.