# US 12,764,459 B2 · Sound reproduction method, sound reproduction device, and recording medium > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,764,459 B2 - Document ID: US12764459B2 - Status: Granted - Kind: B2 - Application number: 18/373,484 - Filed: 2023-09-27 - Published: 2024-01-18 - Granted: 2026-10-13 - Earliest claimed: 2021-04-12 - Assignees: Panasonic Intellectual Property Corporation of America - Applicants: Panasonic Intellectual Property Corporation of America - Inventors: Hikaru Usami; Tomokazu Ishikawa - Web page: https://patentgrep.com/patent/US12764459B2 ## CPC - H04R 1/345: {for loudspeakers} - H04R 3/04: for correcting frequency response - H04R: LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS (producing sounds with frequency not determined by supply frequency G10K) ## Abstract A sound reproduction method includes: obtaining spatial information for reproducing a virtual space which includes a structure and a sound source; identifying a listening position in the virtual space; generating one or more virtual sound sources for reproducing diffraction of sound emitted from the sound source, the one or more virtual sound sources being disposed in a neighborhood of one or more virtual sound source directions; and determining the one or more virtual sound sources based on a length of a propagation path of the sound from the sound source to a listener, the propagation path bypassing the structure. The determining includes determining at least one of (i) a sound pressure level of sound from the one or more virtual sound source directions, (ii) a total number of the one or more virtual sound sources, or (iii) a frequency characteristic of sound from the one or more virtual sound sources. ## Claims ### Claim 1 A sound reproduction method comprising: obtaining spatial information including information about each of a structure and a sound source disposed in a virtual space; obtaining acoustic information including an audio signal indicating sound by the sound source disposed in the virtual space, information about the virtual space, and second spatial information including position information of the sound source and the structure disposed in the space; identifying a listening position of a listener in the virtual space; determining, when the structure is disposed between the sound source and the listening position in the virtual space, at least one of (i) a sound pressure level of sound to be heard by the listener from each of one or more sound source directions, (ii) a total number of one or more sound sources, or (iii) a frequency characteristic of sound emitted from the one or more sound sources, based on a length of a propagation path bypassing the structure, the propagation path being a propagation path of the sound from the sound source to the listener; and in order to reproduce diffraction sound of the sound source, generating one or more virtual sound sources that are disposed in a neighborhood on one or more directions from the listening position toward one or more ends of the structure, and generating an audio stream for output using a head-related transfer function according to the one or more virtual sound sources generated and the listening position of the listener, wherein the total number of the one or more sound sources is determined to increase as the length of the propagation path increases. ### Claim 2 (depends on 1) The sound reproduction method according to claim 1, wherein the sound pressure level is determined by adjusting a sound pressure level of the sound emitted from the one or more sound sources to decrease as the length of the propagation path increases. ### Claim 3 (depends on 1) The sound reproduction method according to claim 1, wherein the sound pressure level is determined by adjusting a position of each of the one or more sound sources to be further away from the listening position as the length of the propagation path increases. ### Claim 4 (depends on 1) The sound reproduction method according to claim 1, wherein the frequency characteristic is determined to set a sound pressure level in a high frequency range to be relatively lower than a sound pressure level in a low frequency range as the length of the propagation path increases. ### Claim 5 (depends on 4) The sound reproduction method according to claim 4, wherein the frequency characteristic is adjusted to increase a bandwidth of the high frequency range in which the sound pressure level is set to be relatively lower than the sound pressure level in the low frequency range, as the length of the propagation path increases. ### Claim 6 (depends on 1) The sound reproduction method according to claim 1, wherein, when two propagation paths, each of which is the propagation path, are formed with the structure interposed therebetween, the one or more sound sources are disposed in each of two sound source directions corresponding to the two propagation paths. ### Claim 7 (depends on 1) The sound reproduction method according to claim 1, wherein, when a single propagation path, which is the propagation path, is formed passing only on one side of the structure, the one or more sound sources are disposed only in a single sound source direction corresponding to the single propagation path, and the one or more sound sources are plural in number. ### Claim 8 (depends on 1) The sound reproduction method according to claim 1, wherein the neighborhood includes an angular range of ±45 degrees with respect to the sound source direction. ### Claim 9 (depends on 1) The sound reproduction method according to claim 1, wherein the information about the structure includes shape information and position information about the structure; and the length of the propagation path is specified based on the shape information, the position information, and the listening position. ### Claim 10 (depends on 9) The sound reproduction method according to claim 9, wherein the shape information includes information indicating a thickness of the structure; and in the determining, the propagation path is set to be longer as the thickness is larger. ### Claim 11 (depends on 1) The sound reproduction method according to claim 1, further comprising: detecting a change in the listening position; and adjusting at least one of the sound pressure level, the total number of the one or more sound sources, or the frequency characteristic based on the change. ### Claim 12 (depends on 11) The sound reproduction method according to claim 11, wherein the change in the listening position is detected by obtaining sensor information indicating the position of the listener at a regular time interval. ### Claim 13 (depends on 11) The sound reproduction method according to claim 11, wherein the change in the listening position is detected based on input information indicating the position of the listener. ### Claim 14 A sound reproduction device comprising: a spatial information obtainer which obtains spatial information including information about each of a structure and a sound source disposed in a virtual space; an acoustic information obtainer which obtains acoustic information including an audio signal indicating sound by the sound source disposed in the virtual space, information about the virtual space, and second spatial information including position information of the sound source and the structure disposed in the space; an identifier which identifies a listening position of a listener in the virtual space; and a generator which determines, when the structure is disposed between the sound source and the listening position in the virtual space, at least one of (i) a sound pressure level of sound to be heard by the listener from each of one or more sound source directions, (ii) a total number of one or more sound sources, or (iii) a frequency characteristic of sound emitted from the one or more sound sources, based on a length of a propagation path bypassing the structure, the propagation path being a propagation path of the sound from the sound source to the listener, and in order to reproduce diffraction sound of the sound source, generates one or more virtual sound sources that are disposed in a neighborhood on one or more directions from the listening position toward one or more ends of the structure, and generates an audio stream for output using a head-related transfer function according to the one or more virtual sound sources generated and the listening position of the listener, wherein the total number of the one or more sound sources is determined to increase as the length of the propagation path increases. ### Claim 15 A non-transitory computer-readable recording medium having recorded thereon a program for causing a computer to execute a sound reproduction method, the sound reproduction method comprising: obtaining spatial information including information about each of a structure and a sound source disposed in a virtual space; obtaining acoustic information including an audio signal indicating sound by the sound source disposed in the virtual space, information about the virtual space, and second spatial information including position information of the sound source and the structure disposed in the space; identifying a listening position of a listener in the virtual space; determining, when the structure is disposed between the sound source and the listening position in the virtual space, at least one of (i) a sound pressure level of sound to be heard by the listener from each of one or more sound source directions, (ii) a total number of one or more sound sources, or (iii) a frequency characteristic of sound emitted from the one or more sound sources, based on a length of a propagation path bypassing the structure, the propagation path being a propagation path of the sound from the sound source to the listener; in order to reproduce diffraction sound of the sound source, generating one or more virtual sound sources that are disposed in a neighborhood on one or more directions from the listening position toward one or more ends of the structure, and generating an audio stream for output using a head-related transfer function according to the one or more virtual sound sources generated and the listening position of the listener, wherein the total number of the one or more sound sources is determined to increase as the length of the propagation path increases.