An audio system includes at least one acoustic transducer having at least one a group of: a membrane and an acoustic modulator; or a membrane, acoustic resonator, and acoustic coupler; at least one microphone receiving an acoustic signal; a substrate; and a package. The at least one acoustic transducer and one microphone are attached to the substrate and encapsulated by the package.

A speaker (10) includes a radiation surface (15). The radiation surface (15) has a first region (15a), a second region (15b), and a third region (15c) between the first region (15a) and the second region (15b). When an axis passing through the third region (15c) and extending away from the radiation surface (15) is defined as a reference axis (10X), the speaker (10) forms a first wavefront (16a) propagating from the first region so as to approach the reference axis (10X) and a second wavefront (16b) propagating from the second region (15b) so as to approach the reference axis (10X).

[Problem] To provide a technology capable of suppressing sound leakage to the outside of a room even when a user listens to audio in the room at a preferred sound volume. [Solution] This multi-channel audio device 1 performs sound output on audio playback signals from channels through respective playback speakers 2, and performs sound output on antiphase signals of the audio playback signals through an antiphase speaker 3. The attenuation rates and the delay times of the audio playback signals output from the respective playback speakers 2 at the installation position of the antiphase speaker 3 are stored in advance, and during the audio playback, the antiphase signals of the audio playback signals of the respective channels are attenuated on the basis of the respective attenuation rates, are delayed on the basis of the respective delay times, and are output as sound from the antiphase speaker 3.