The acoustic device 10D illustrated in FIG. 5 reproduces the left ear signal with unidirectional directivity by using the speakers 11LP and 11LS arranged back-to-back. Therefore, with regard to the left ear signal reproduced by the speakers 11LP and 11LS, the level of sound that propagates toward a right ear direction of the listener M becomes lower than the level of sound that propagates toward a left ear direction of the listener M (indicated by an arrow a), and this makes it possible to reduce a crosstalk component related to the left ear signal.
In this case, the left ear signal having the unidirectional directivity is reproduced. Therefore, the level of sound that propagates toward the right ear direction becomes higher than the reproduced sound having the bidirectional directivity like in the case of the acoustic device 10A illustrated in FIG. 1, but it is possible to drastically reduce the level of sound that propagates toward the back surface side. In addition, the acoustic device 10D reproduces the right ear signal with unidirectional directivity by using the speakers 11RP and 11RS arranged back-to-back. This also makes it possible to reduce a crosstalk component related to the right ear signal in a similar way.
