A technology is provided that reduces noise heard when a user sits in a seat of an aircraft, without using earphones or headphones. A sound system includes: a control system that generates a control signal for canceling noise in a place close to a head of a user using a seat of an aircraft, from a signal of the noise (noise signal); and a noise-cancellation speaker system including speaker units that emit sound based on the control signal (first noise-cancellation speaker unit, . . . , M-th noise-cancellation speaker unit), the noise-cancellation speaker system being installed at the place close to the head of the user using the seat, wherein assuming that a direction in which the m-th noise-cancellation speaker unit faces the user is an m-th noise-cancellation user direction, the m-th noise-cancellation speaker unit is disposed such that sound emitted from the m-th noise-cancellation speaker unit in the m-th noise-cancellation user direction is canceled in a place other than the place close to the head of the user using the seat, due to bending around of sound emitted from the m-th noise-cancellation speaker unit in an opposite direction to the m-th noise-cancellation user direction.
1. A sound system comprising:
a control system that generates a control signal for canceling noise in a place close to a head of a user using a seat of an aircraft, from a signal of the noise (hereinafter, referred to as the noise signal); and
a noise-cancellation speaker system including M speaker units that emit sound based on the control signal (hereinafter, referred to as the noise-cancellation speaker units), M being an integer equal to or larger than one, the noise-cancellation speaker system being installed at the place close to the head of the user using the seat, wherein
assuming that the M noise-cancellation speaker units are a first noise-cancellation speaker unit, . . . , and an M-th noise-cancellation speaker unit, and
assuming that a direction in which the m-th noise-cancellation speaker unit faces the user is an m-th noise-cancellation user direction (m=1, . . . , M),
the m-th noise-cancellation speaker unit (m=1, . . . , M) is disposed such that sound emitted from the m-th noise-cancellation speaker unit in the m-th noise-cancellation user direction is canceled in a place other than the place close to the head of the user using the seat, due to bending around of sound emitted from the m-th noise-cancellation speaker unit in an opposite direction to the m-th noise-cancellation user direction,
wherein a member is attached to the m-th noise-cancellation speaker unit (m=1, . . . , M), the member being for lengthening a path of the sound bending around in the m-th noise-cancellation user direction, of the sound emitted from the m-th noise-cancellation speaker unit in the opposite direction to the m-th noise-cancellation user direction.
2. The sound system according to claim 1 , further comprising:
a reproduction apparatus including an n-th reproduction unit (n=1, . . . , N) that outputs a (2n−1)-th sound signal that is a sound signal obtained based on a subject to be reproduced, and a 2n-th sound signal that is a sound signal with opposite phase to phase of the (2n−1)-th sound signal, N being an integer equal to or larger than one; and
a speaker system including an n-th speaker unit pair (n=1, . . . , N) including a speaker unit that emits sound based on the (2n−1)-th sound signal (hereinafter, referred to as the positive speaker unit) and a speaker unit that emits sound based on the 2n-th sound signal (hereinafter, referred to as the negative speaker unit), the speaker system being installed at the place close to the head of the user using the seat.
3. The sound system according to claim 2 , wherein the positive speaker unit and the negative speaker unit of the n-th speaker unit pair (n=1, . . . , N) are disposed in a positional relationship in which the sound emitted from the positive speaker unit and the sound emitted from the negative speaker unit cancel each other out so that the sound is not heard by another user using a seat other than the seat.
4. The sound system according to claim 2 , wherein
assuming that a direction in which the n-th speaker unit pair faces the user is an n-th user direction (n=1, . . . , N),
the positive speaker unit and the negative speaker unit of the n-th speaker unit pair (n=1, . . . , N) are disposed such that sound emitted from the positive speaker unit in an opposite direction to the n-th user direction and sound emitted from the negative speaker unit in the opposite direction to the n-th user direction propagate in the n-th user direction due to bending around of the sound.