# US 9,883,315 B2 · Systems and methods for calibrating speakers > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,883,315 B2 - Document ID: US9883315B2 - Status: Granted - Kind: B2 - Application number: 15/250,870 - Filed: 2016-08-29 - Published: 2016-12-22 - Granted: 2018-01-30 - Earliest claimed: 2012-02-21 - Assignees: Intertrust Technologies Corporation - Applicants: Intertrust Technologies Corporation - Inventors: David P. Maher; Gilles Boccon-Gibod; Steve Mitchell - Web page: https://patentgrep.com/patent/US9883315B2 ## CPC - H04S 7/301: {Automatic calibration of stereophonic sound system, e.g. with test microphone} - H04R 3/04: for correcting frequency response - H04R 5/02: Spatial or constructional arrangements of loudspeakers - H04S 7/302: {Electronic adaptation of stereophonic sound system to listener position or orientation (H04S7/301 takes precedence)} - H04S 7/307: {Frequency adjustment, e.g. tone control (H04S7/301 takes precedence)} - H04R 27/00: Public address systems (circuits for preventing acoustic reaction H04R3/02; circuits for distributing signals to loudspeakers H04R3/12; {monitoring or testing arrangements for public address systems H04R29/007}; amplifiers H03F) - H04R 29/004: {for microphones (H04R29/007 takes precedence)} - H04R 29/007: {for public address systems (public address systems per se H04R27/00)} - H04R 2205/021: Aspects relating to docking-station type assemblies to obtain an acoustical effect, e.g. the type of connection to external loudspeakers or housings, frequency improvement - H04R 2227/003: Digital PA systems using, e.g. LAN or internet - H04R 2227/005: Audio distribution systems for home, i.e. multi-room use - H04R 2499/11: Transducers incorporated or for use in hand-held devices, e.g. mobile phones, PDA's, camera's - 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 Systems and method are disclosed for facilitating efficient calibration of filters for correcting room and/or speaker-based distortion and/or binaural imbalances in audio reproduction, and/or for producing three-dimensional sound in stereo system environments. According to some embodiments, using a portable device such as a smartphone or tablet, a user can calibrate speakers by initiating playback of a test signal, detecting playback of the test signal with the portable device's microphone, and repeating this process for a number of speakers and/or device positions (e.g., next to each of the user's ears). A comparison can be made between the test signal and the detected signal, and this can be used to more precisely calibrate rendering of future signals by the speakers. ## Claims ### Claim 1 A method for calibrating speakers for a particular environment, the method comprising: positioning a microphone of a portable device at a first location in an environment; initiating first playback by an audio source of a piece of audio content over a speaker; detecting the first playback of the piece of audio content by the microphone at the first location; positioning a microphone at a second location in the environment, the second location being different from the first location; initiating second playback by the audio source of the piece of audio content over the speaker; detecting the second playback of the piece of audio content using the microphone at the second location; determining, based at least in part on the detected first playback of the piece of audio content and the detected second playback of the piece of audio content, one or more adjustments to be applied to additional audio content before additional audio content playback by the speaker, wherein determining the one or more adjustments comprises: accessing a system information file of the portable device to determine a transfer function of the microphone; and determining the one or more adjustments using, at least in part, the transfer function of the microphone; and applying the one or more adjustments to the additional audio content before it is played by the speaker. ### Claim 2 (depends on 1) The method of claim 1, wherein the first location comprises a position proximate to a first ear of a person within the environment. ### Claim 3 (depends on 2) The method of claim 2, wherein the second location comprises a position proximate to a second ear of a person within the environment. ### Claim 4 (depends on 1) The method of claim 1, wherein the piece of audio content comprises one or more synchronization patterns. ### Claim 5 (depends on 4) The method of claim 4, wherein determining the one or more adjustments to be applied to the additional audio content further comprises aligning the detected first playback of the piece of audio content and the detected second playback of the piece of audio content based, at least in part, on the one or more synchronization patterns. ### Claim 6 (depends on 1) The method of claim 1, wherein the portable device comprises a mobile phone. ### Claim 7 (depends on 1) The method of claim 1, wherein the portable device comprises a tablet. ### Claim 8 (depends on 1) The method of claim 1, wherein determining the one or more adjustments to be applied to the additional audio content further comprises performing spectral analysis on the detected first playback of the piece of audio content and the detected second playback of the piece of audio content. ### Claim 9 (depends on 8) The method of claim 8, wherein determining the one or more adjustments to be applied to the additional audio content further comprises comparing a frequency response of the detected first playback of the piece of audio content with an ideal frequency response. ### Claim 10 (depends on 1) The method of claim 1, wherein determining a transfer function of the microphone comprises: retrieving a mobile device identifier from the system information file; and retrieving the transfer function of the microphone from a set of microphone transfer functions using a web service. ### Claim 11 A portable device for calibrating speakers for a particular environment, the portable device comprising: a microphone; a processor; and a non-transitory memory storing instructions that when executed by the processor of the portable device cause the portable device to perform operations comprising: providing instructions for positioning the microphone of the portable device at a first location in an environment; initiating first playback by an audio source of a piece of audio content over a speaker; detecting the first playback of the piece of audio content by the microphone at the first location; providing instructions for positioning a microphone at a second location in the environment, the second location being different from the first location; initiating second playback by the audio source of the piece of audio content over the speaker; detecting the second playback of the piece of audio content using the microphone at the second location; determining, based at least in part on the detected first playback of the piece of audio content and the detected second playback of the piece of audio content, one or more adjustments to be applied to additional audio content before additional audio content playback by the speaker, wherein determining the one or more adjustments comprises: accessing a system information file of the portable device to determine a transfer function of the microphone; and determining the one or more adjustments using, at least in part, the transfer function of the microphone; and applying the one or more adjustments to the additional audio content before it is played by the speaker. ### Claim 12 (depends on 11) The portable device of claim 11, wherein the first location comprises a position proximate to a first ear of a person within the environment. ### Claim 13 (depends on 12) The portable device of claim 12, wherein the second location comprises a position proximate to a second ear of a person within the environment. ### Claim 14 (depends on 11) The portable device of claim 11, wherein the piece of audio content comprises one or more synchronization patterns. ### Claim 15 (depends on 14) The portable device of claim 14, wherein determining the one or more adjustments to be applied to the additional audio content further comprises aligning the detected first playback of the piece of audio content and the detected second playback of the piece of audio content based, at least in part, on the one or more synchronization patterns. ### Claim 16 (depends on 11) The portable device of claim 11, wherein the portable device comprises a mobile phone. ### Claim 17 (depends on 11) The portable device of claim 11, wherein the portable device comprises a tablet. ### Claim 18 (depends on 11) The portable device of claim 11, wherein determining the one or more adjustments to be applied to the additional audio content further comprises performing spectral analysis on the detected first playback of the piece of audio content and the detected second playback of the piece of audio content. ### Claim 19 (depends on 18) The portable device of claim 18, wherein determining the one or more adjustments to be applied to the additional audio content further comprises comparing a frequency response of the detected first playback of the piece of audio content with an ideal frequency response. ### Claim 20 (depends on 11) The portable device of claim 11, wherein determining a transfer function of the microphone comprises: retrieving a mobile device identifier from the system information file; and retrieving the transfer function of the microphone from a set of microphone transfer functions using a web service.