Abstract: Provided is an acoustic system for a user who uses a seat of an aircraft, an automobile, or the like, which reproduces a sound that cannot be heard by surrounding users without using earphones or headphones.

Abstract: There is provided an acoustic system for a user who uses a seat of an airplane, an automobile, or the like, which reproduces a sound that cannot be heard by surrounding users without using earphones or headphones. An acoustic system including a speaker system including one speaker unit that emits a sound based on an acoustic signal of a predetermined sound source, in which a sound emitted from the speaker unit is hearable in a region to be audible near the speaker unit, and by a sound emitted from the speaker unit in a back surface direction coming around to a front surface direction, the sound emitted from the speaker unit in the front surface direction and the sound emitted from the speaker unit in the back surface direction cancel each other in a region in the front surface direction far from the speaker unit.

Abstract: Provided is an acoustic system for a user who uses a seat of an aircraft, an automobile, or the like, which reproduces a sound that cannot be heard by surrounding users without using earphones or headphones.

Abstract: A sound that cannot be heard by surrounding users is reproduced. A reproduction device (110) includes an n-th reproduction unit that outputs a 2n?1th acoustic signal (n=1, . . . , N) that is an acoustic signal obtained on the basis of a reproduction target and a 2n-th acoustic signal that is an acoustic signal having a phase opposite to that of the 2n?1th acoustic signal. A speaker system (120) includes a set of an n-th speaker unit pair (122) including a positive speaker unit (1221) that emits a 2n?1th acoustic signal-based sound and a negative speaker unit (1222) that emits a 2n-th acoustic signal-based sound, the n-th speaker unit pair being installed at a position close to a user's head.

Abstract: Two speaker units are arranged on the right side from the center of a seat; two speaker units are arranged on the left side from the center of the seat; one of the two speaker units arranged on the right side is arranged at a position closer to the right ear of a user seated on the seat as compared with the other one of the two speaker units arranged on the right side; one of the two speaker units arranged on the left side is arranged at a position closer to the left ear of the user seated on the seat as compared with the other one of the two speaker units arranged on the left side; acoustic signals obtained on the basis of a reproduction target are emitted from the two speaker units arranged on the right side to be opposite in phase to each other; the acoustic signals obtained on the basis of the reproduction target are emitted from the two speaker units arranged on the left side to be opposite in phase to each other; and the acoustic signals are emitted from two speaker units arranged on the positions close

Abstract: A sound system includes: a control system that generates a control signal for erasing noise from a signal of the noise in a place close to a head of a user who uses a seat; a silencing speaker system that is installed at the place close to the head of the user who uses the seat and includes M speaker units each emitting a sound based on the control signal; and an emission suppression unit including at least a sound absorbing material that easily absorbs only a sound having a frequency greater than or equal to a predetermined value and configured to make it difficult for the sound having the frequency greater than or equal to the predetermined value emitted from the silencing speaker units to be emitted to a place other than an ear of the user.

Abstract: Two speaker units are arranged on the right side from the center of a seat; two speaker units are arranged on the left side from the center of the seat; one of the two speaker units arranged on the right side is arranged at a position closer to the right ear of the user seated on the seat as compared with the other one of the two speaker units arranged on the right side; one of the two speaker units arranged on the left side is arranged at a position closer to the left ear of the user seated on the seat as compared with the other one of the two speaker units arranged on the left side; acoustic signals of a reproduction target are emitted from the two speaker units arranged on the right side to be opposite in phase to each other; the acoustic signals of the reproduction target are emitted from the two speaker units arranged on the left side to be opposite in phase to each other; and the acoustic signals are emitted from the two speaker units arranged at positions closer to the ears not to be opposite in phase

Abstract: A sound that cannot be heard by surrounding users is reproduced. A reproduction device (110) includes an n-th reproduction unit that outputs a 2n?1th acoustic signal (n=1, . . . , N) that is an acoustic signal obtained on the basis of a reproduction target and a 2n-th acoustic signal that is an acoustic signal having a phase opposite to that of the 2n?1th acoustic signal. A speaker system (120) includes at least two or more sets of an n-th speaker unit pair (122) including a positive speaker unit (1221) that emits a 2n-1th acoustic signal-based sound and a negative speaker unit (1222) that emits a 2n-th acoustic signal-based sound, the n-th speaker unit pair being installed at a position close to a user's head.

Abstract: Provided is a technology for generating an elimination filter coefficient for suppressing degradation of noise elimination performance.

Abstract: Provided is a technique for selecting a cancellation filter coefficient that can stably cancel noise for a user using a seat of an aircraft, an automobile, or the like. A cancellation filter coefficient selection apparatus includes: a recording unit configured to record cancellation filter coefficients; a seat position acquisition unit configured to acquire a position of a seat used by a user; and a cancellation filter coefficient selection unit configured to, from among the cancellation filter coefficients recorded in the recording unit, select a cancellation filter coefficient corresponding to the position of the seat as a cancellation filter coefficient to be used in filtering for generating a cancellation signal for cancelling noise at a position where quiet is desired, based on a reference signal output by a reference microphone configured to collect noise in a predetermined space.

Abstract: A sound system, for a user using a seat of an aircraft, an automobile, or the like, that reproduces sound inaudible to users around, without using earphones or headphones, is provided. A sound system for a user using a seat of an aircraft includes: 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 a place close to a head of the user using the seat.

Abstract: A speaker system that reproduces sound inaudible to users around, without using earphones, headphones, or a large-scale speaker array, is provided. Assuming that N is an integer equal to or larger than one, and that a (2n?1)-th sound signal (n=1, . . . , N) is a sound signal obtained based on a subject to be reproduced, a speaker system that emits sound based on a first sound signal, . . . , and sound based on a (2N?1)-th sound signal such that the sound is heard only in a vicinity, includes 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 a 2n-th sound signal that is a sound signal with opposite phase to phase of the (2n?1)-th sound signal (hereinafter, referred to as the negative speaker unit).

Abstract: A vibration cancellation method is a vibration cancellation method for canceling vibration arriving at a seat from outside of the seat, the vibration being transmitted to a user seated in the seat. The method includes canceling, by a vibration cancellation unit (4), a vibration by outputting a cancellation signal from a position close to a position where user's head is placed when a user is seated, the cancellation signal being obtained based on a reference signal and an error signal. The reference signal is obtained by a vibration sensor (2) disposed in a position close to a vibration source outside the seat in the seat, and the error signal is obtained by an error vibration sensor (3) disposed in the position close to the position where user's head is placed when the user is seated in the seat.

Abstract: 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, . . .

Abstract: The number of conversational tests needed for the evaluation of acoustic quality of the ICC system is reduced. An evaluation value conversion device 3 evaluates the quality of communication between a near-end acoustic region 100 and a far-end acoustic region 200 inside a vehicle for which a plurality of acoustic regions are predetermined. A voice signal picked up by a microphone M2 disposed in the far-end acoustic region 200 is emitted from a speaker S1 disposed in the near-end acoustic region 100.

Abstract: An object is to provide a sound collection apparatus capable of collecting a sound with a higher SN rate than before through use of a reflected sound. The sound collection apparatus is installed in a vehicle. The vehicle includes a seat for a passenger to sit on, and a reflective structure that reflects a sound emitted by a passenger sitting in the seat. The sound collection apparatus includes a first microphone arranged at a position where a direct sound that is a sound emitted by the passenger is readily collected, and a second microphone arranged at a position where a reflected sound that is a sound emitted by the passenger and reflected by the reflective structure is readily collected.

Abstract: Provided is an echo cancellation apparatus capable of calculating an acoustic coupling amount with high accuracy regardless of the magnitude of the near-end speaker component and without using a double talk detector. The echo cancellation apparatus cancels an echo included in a sound pickup signal picked up by a microphone placed at a near-end and includes an acoustic coupling amount calculation unit that updates and calculates an acoustic coupling amount estimated value of a component of a reproduction signal, which is a signal picked up by a microphone placed at a far-end included in the sound pickup signal, such that an update amount is decreased the greater a magnitude of a component other than an echo component is in the sound pickup signal; a gain calculation unit that calculates a gain coefficient on the basis of the acoustic coupling amount estimated value; and an integration unit that integrates the gain coefficient with the sound pickup signal and generates an echo cancellation signal.

Abstract: An object is to provide a sound collection apparatus capable of collecting a sound with a higher SN rate than before through use of a reflected sound. The sound collection apparatus is installed in a vehicle. The vehicle includes a seat for a passenger to sit on, and a reflective structure that reflects a sound emitted by a passenger sitting in the seat. The sound collection apparatus includes a first microphone arranged at a position where a direct sound that is a sound emitted by the passenger is readily collected, and a second microphone arranged at a position where a reflected sound that is a sound emitted by the passenger and reflected by the reflective structure is readily collected.

Abstract: In encoding, a frequency-domain sample sequence derived from an acoustic signal is divided by a weighted envelope and is then divided by a gain, the result obtained is quantized, and each sample is variable-length encoded. The error between the sample before quantization and the sample after quantization is quantized with information saved in this variable-length encoding. This quantization is performed under a rule that specifies, according to the number of saved bits, samples whose errors are to be quantized. In decoding, variable-length codes in an input sequence of codes are decoded to obtain a frequency-domain sample sequence; an error signal is further decoded under a rule that depends on the number of bits of the variable-length codes; and from the obtained sample sequence, the original sample sequence is obtained according to supplementary information.

Abstract: In encoding, a frequency-domain sample sequence derived from an acoustic signal is divided by a weighted envelope and is then divided by a gain, the result obtained is quantized, and each sample is variable-length encoded. The error between the sample before quantization and the sample after quantization is quantized with information saved in this variable-length encoding. This quantization is performed under a rule that specifies, according to the number of saved bits, samples whose errors are to be quantized. In decoding, variable-length codes in an input sequence of codes are decoded to obtain a frequency-domain sample sequence; an error signal is further decoded under a rule that depends on the number of bits of the variable-length codes; and from the obtained sample sequence, the original sample sequence is obtained according to supplementary information.