# US 12,604,150 B2 · Method and system for spatial audio processing using multiple orders of ambisonics > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,604,150 B2 - Document ID: US12604150B2 - Status: Granted - Kind: B2 - Application number: 18/476,280 - Filed: 2023-09-27 - Published: 2025-03-27 - Granted: 2026-04-14 - Earliest claimed: 2023-09-27 - Assignees: Apple Inc. - Applicants: Apple Inc. - Inventors: Symeon Delikaris Manias - Web page: https://patentgrep.com/patent/US12604150B2 ## CPC - H04S 7/30: {Control circuits for electronic adaptation of the sound field} - H04R 5/04: Circuit arrangements, {e.g. for selective connection of amplifier inputs/outputs to loudspeakers, for loudspeaker detection, or for adaptation of settings to personal preferences or hearing impairments (combinations of amplifiers H03F3/68; stereophonic systems H04S)} - H04S 2420/01: Enhancing the perception of the sound image or of the spatial distribution using head related transfer functions [HRTF's] or equivalents thereof, e.g. interaural time difference [ITD] or interaural level difference [ILD] - H04S 2420/11: Application of ambisonics in stereophonic audio systems - H04S: STEREOPHONIC SYSTEMS - 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 method that includes receiving a higher-order ambisonics (HOA) representation of a sound field that includes a first plurality of audio signals, separating a second plurality of audio signals from the first plurality of audio signals that are associated with a first-order ambisonics (FOA) representation of the sound field, determining a plurality of adaptive filters based on at least some of the second plurality of audio signals, producing a plurality of output audio signals based on the first plurality of audio signals and the plurality of adaptive filters, each output audio signal having at least a portion of the sound field, and driving a plurality of speakers using the plurality of output audio signals. ## Claims ### Claim 1 A method comprising: receiving a higher-order ambisonics (HOA) representation of a sound field that includes a first plurality of audio signals; separating a second plurality of audio signals from the first plurality of audio signals, wherein the second plurality of audio signals are of a first-order ambisonics (FOA) representation of the sound field; determining a plurality of adaptive filters based on at least some of the second plurality of audio signals; producing a plurality of output audio signals based on the first plurality of audio signals and the plurality of adaptive filters, each output audio signal having at least a portion of the sound field; and driving a plurality of speakers using the plurality of output audio signals. ### Claim 2 (depends on 1) The method of claim 1, wherein producing the plurality of output audio signals comprises: rendering the first plurality of audio signals to produce a plurality of speaker driver signals; and applying at least one of the plurality of adaptive filters to at least one of the plurality of speaker driver signals. ### Claim 3 (depends on 2) The method of claim 2 further comprising determining a speaker layout of the plurality of speakers, wherein the first plurality of audio signals are rendered according to the speaker layout. ### Claim 4 (depends on 3) The method of claim 3, wherein, when the speaker layout comprises headphones, rendering further comprises applying at least one spatial audio filter to each of the plurality of output audio signals. ### Claim 5 (depends on 1) The method of claim 1, wherein the plurality of adaptive filters are determined according to a speaker layout of the plurality of speakers. ### Claim 6 (depends on 1) The method of claim 1 further comprising performing a sound field analysis upon the second plurality of audio signals to determine one or more parameters associated with the sound field, wherein the plurality of adaptive filters are determined based on the least some of the second plurality of audio signals and the one or more parameters. ### Claim 7 (depends on 6) The method of claim 6, wherein the one or more parameters comprises at least one of a direction of arrival (DOA) associated with a sound source of the sound field, diffuseness of the sound field, reverberance of the sound field, and direct-to-ambience ratio of sound of the sound field. ### Claim 8 (depends on 1) The method of claim 1, wherein HOA representation of the sound field is of user-desired audio content, the method further comprises playing back, by an electronic device, the user-desired audio content through the plurality of speakers, wherein the receiving, separating, determining, producing, and driving are performed while the user-desired audio content is played back by the electronic device. ### Claim 9 (depends on 1) The method of claim 1, wherein the plurality of output audio signals is a first plurality of output audio signals, wherein the method further comprises: determining that the plurality of adaptive filters are no longer to be determined; in response, rendering the second plurality of audio signals to produce a second plurality of output audio signals; and driving the plurality of speakers using the second plurality of output audio signals in lieu of the first plurality of output audio signals. ### Claim 10 (depends on 9) The method of claim 9 is performed by at least one programmed processor of an electronic device, wherein the method further comprises determining a computational load on the electronic device, wherein determining that the plurality of adaptive filters are no longer to be determined comprises determining that the computational load is above a threshold. ### Claim 11 An electronic device, comprising: at least one processor; and memory having instructions stored therein which when executed by the at least one processor causes the electronic device to: receive a higher-order ambisonics (HOA) representation of a sound field that includes a first plurality of audio signals; extract a second plurality of audio signals from the first plurality of audio signals, wherein the second plurality of audio signals are of a first-order ambisonics (FOA) representation of the sound field; determine a plurality of adaptive filters based on at least some of the second plurality of audio signals; produce a plurality of output audio signals based on the first plurality of audio signals and the plurality of adaptive filters, each output audio signal having at least a portion of the sound field; and drive a plurality of speakers using the plurality of output audio signals. ### Claim 12 (depends on 11) The electronic device of claim 11, wherein the plurality of speakers are a part of the electronic device. ### Claim 13 (depends on 11) The electronic device of claim 11, wherein the electronic device is a first electronic device, wherein the instructions to drive the plurality of speakers comprises instructions to transmit the plurality of output audio signals to a second electronic device that comprises or is communicatively coupled to the plurality of speakers to cause the second electronic device to playback the plurality of output audio signals. ### Claim 14 (depends on 11) The electronic device of claim 11, wherein the instructions to produce the plurality of output audio signals comprises instructions to: render the first plurality of audio signals to produce a plurality of speaker driver signals; and apply at least one of the plurality of adaptive filters to at least one of the plurality of speaker driver signals. ### Claim 15 (depends on 11) The electronic device of claim 11, wherein the memory has further instructions to perform a sound field analysis upon the second plurality of audio signals to determine one or more parameters associated with the sound field, wherein the plurality of adaptive filters are determined based on the least some of the second plurality of audio signals and the one or more parameters. ### Claim 16 (depends on 15) The electronic device of claim 15, wherein the one or more parameters comprises at least one of a direction of arrival (DOA) associated with a sound source of the sound field, diffuseness of the sound field, reverberance of the sound field, and direct-to-ambience ratio of sound of the sound field. ### Claim 17 (depends on 11) The electronic device of claim 11, wherein the plurality of output audio signals is a first plurality of output audio signals, wherein the memory has further instructions to: determine a computational load on the electronic device; in response to determining that the plurality of adaptive filters are no longer to be determined based on the computational load, render the second plurality of audio signals to produce a second plurality of output audio signals; and drive the plurality of speakers using the second plurality of output audio signals in lieu of the first plurality of output audio signals. ### Claim 18 A processor of an electronic device configured to: extract a first-order ambisonics (FOA) signal from a higher-order ambisonics (HOA) signal; perform non-parametric spatial audio rendering upon the HOA signal to produce a plurality of spatially rendered audio signals; perform parametric spatial audio processing upon the FOA signal to estimate one or more adaptive filters; produce a plurality of output audio signals by applying the one or more adaptive filters upon the plurality of spatially rendered audio signals; and cause a plurality of speakers to playback the plurality of output audio signals. ### Claim 19 (depends on 18) The processor of claim 18, wherein performing the parametric spatial audio processing comprises performing a sound field analysis upon the FOA signal to determine one or more parameters associated with a sound field of the FOA signal, wherein the one or more parameters comprises at least one of a direction of arrival (DOA) associated with a sound source of the sound field, diffuseness of the sound field, reverberance of the sound field, and direct-to-ambience ratio of sound of the sound field, and wherein the one or more adaptive filters are determined based on the FOA signal and the one or more parameters. ### Claim 20 (depends on 18) The processor of claim 18, wherein the processor is configured to determine a computational load on the electronic device; in response to determining that the computational load is greater than a threshold, cease performing the parametric spatial audio processing; and cause the plurality of speakers to playback the plurality of spatially rendered audio signals in lieu of the plurality of output audio signals.