Sound system

A sound system that emits, by using at least four speaker units arranged in a seat of a vehicle, acoustic signals of a reproduction target such that the acoustic signals are not able to be heard or hardly heard outside a first range near a user sitting in the seat, and emits a cancellation sound such that noise cancellation by the cancellation sound for canceling noise arriving at the seat affects only a second range near the user sitting in the seat, wherein

• the at least four speaker units are not housed in speaker boxes,
• sound waves emitted in a direction opposite to the user are diffracted and propagated towards the user by coming around,
• a (2R-1)-th speaker unit and a 2R-th speaker unit that are two speaker units of the at least four speaker units are arranged on a right side from a center of the seat,
• a (2L-1)-th speaker unit and a 2L-th speaker unit that are two speaker units of the at least four speaker units are arranged on a left side from the center of the seat,
• the two speaker units arranged on the right side and the two speaker units arranged on the left side are arranged to sandwich a head of the user,
• the (2R-1)-th speaker unit emits a (2R-1)-th acoustic signal that is one of the acoustic signals of the reproduction target,
• the 2R-th speaker unit emits a 2R-th acoustic signal that is an acoustic signal having a phase opposite to that of the (2R-1)-th acoustic signal,
• the (2L-1)-th speaker unit emits a (2L-1)-th acoustic signal that is one of the acoustic signals of the reproduction target,
• the 2L-th speaker unit emits a 2L-th acoustic signal that is an acoustic signal having a phase opposite to that of the (2L-1)-th acoustic signal, and
• at least either one of:
• the (2R-1)-th speaker unit and the (2L-1)-th speaker unit are arranged closer to a right ear and a left ear of the user sitting in the seat than the 2R-th speaker unit and the 2L-th speaker unit, respectively, or
• the 2R-th speaker unit and the 2L-th speaker unit are arranged closer to the right ear and the left ear of the user sitting in the seat than the (2R-1)-th speaker unit and the (2L-1)-th speaker unit, respectively.

A sound system that emits, by using 2N speaker units, where N is any integer greater than or equal to 2, acoustic signals of a reproduction target such that the acoustic signals are not able to be heard or hardly heard in a range outside a first range near a user sitting in a seat of a vehicle, and emits a cancellation sound such that noise cancellation by the cancellation sound for canceling noise in a second range near the user does not affect a range outside the second range,

• the 2N speaker units are not respectively housed in speaker boxes,
• sound waves emitted in a direction opposite to the user are diffracted and propagated towards the user by coming around,
• the sound system comprising:
• a reproduction device including an n-th reproduction unit that outputs a (2n-1)-th acoustic signal that is one of the acoustic signals of the reproduction target and a 2n-th acoustic signal that is an acoustic signal having a phase opposite to that of the (2n-1)-th acoustic signal, where n=1, . . . , and N;
• and each n is an integer that satisfies 1≤n≤N;
• and
• a speaker system that is installed at a place close to a head of the user sitting in the seat and includes an n-th speaker unit pair (n=1, . . . , N) including a (2n-1)-th speaker unit that emits the (2n-1)-th acoustic signal and a 2n-th speaker unit that emits the 2n-th acoustic signal, wherein
• an R-th speaker unit pair is arranged on a right side from a center of the seat, where R is any integer greater than or equal to 1 and less than or equal to N,
• an L-th speaker unit pair is arranged on a left side from the center of the seat, where L is any integer greater than or equal to 1 and less than or equal to N,
• the R-th speaker unit pair and the L-th speaker unit pair are arranged to sandwich the head of the user, and
• at least either one of:
• a (2R-1)-th speaker unit and a (2L-1)-th speaker unit are arranged closer to a right ear and a left ear of the user sitting in the seat than a 2R-th speaker unit and a 2L-th speaker unit, respectively, or
• the 2R-th speaker unit and the 2L-th speaker unit are arranged closer to the right ear and the left ear of the user sitting in the seat than the (2R-1)-th speaker unit and the (2L-1)-th speaker unit, respectively.