# US 2020/0221241 A1 · Method for determining a phase filter for a system for generating vibrations perceptible by a user comprising several transducers > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2020/0221241 A1 - Document ID: US20200221241A1 - Status: Published application - Kind: A1 - Application number: 16/733,981 - Filed: 2020-01-03 - Published: 2020-07-09 - Earliest claimed: 2019-01-03 - Assignees: Faurecia Clarion Electronics Europe - Applicants: Parrot Faurecia Automotive SAS - Inventors: Grégory Olivier KLEINHANS - Web page: https://patentgrep.com/patent/US20200221241A1 ## CPC - H04S 7/302: {Electronic adaptation of stereophonic sound system to listener position or orientation (H04S7/301 takes precedence)} - H04R 5/02: Spatial or constructional arrangements of loudspeakers - 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 1/002: {Non-adaptive circuits, e.g. manually adjustable or static, for enhancing the sound image or the spatial distribution (control circuits for electronic adaptation of the sound field H04S7/30)} - H04S 7/301: {Automatic calibration of stereophonic sound system, e.g. with test microphone} - H04R 3/12: for distributing signals to two or more loudspeakers {(specially adapted for hearing aids H04R25/407)} - H04R 2499/13: Acoustic transducers and sound field adaptation in vehicles - 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 determining method that makes it possible to determine a phase filter for a system that generates vibrations and that includes a first transducer for converting a first electrical signal and a second transducer for converting a second electrical signal. The method includes: performing, for at least one perception position, of a plurality of spectral measurements of a characteristic parameter of the vibrations generated in this perception position as a function of the frequency, each spectral measurement being done for a respective phase shift value between the first electrical signal and the second electrical signal; and determining a phase filter from spectral measurements done, by selecting, for each frequency, a phase shift value from among the phase shift values used to perform the spectral measurements. ## Claims ### Claim 1 A method for determining a phase filter for a system for generating vibrations perceptible by a user comprising a signal source configured to deliver a first electrical signal and a second electrical signal, and a pair of transducers comprising a first transducer for converting the first electrical signal into vibrations perceptible by a user and a second transducer for converting the second electrical signal into vibrations perceptible by a user, the phase filter being provided to introduce a relative phase shift between the first electrical signal and the second electrical signal, the method comprising: performing, for at least one determined perception position, of a plurality of spectral measurements of a characteristic parameter of the vibrations generated in this perception position as a function of the frequency, each spectral measurement being done for a respective phase shift value between the first electrical signal and the second electrical signal, and determining a phase filter from spectral measurements done, by selecting, for each frequency, a phase shift value from among the phase shift values used to perform the spectral measurements. ### Claim 2 (depends on 1) The determining method according to claim 1, wherein the step for performing spectral measurements comprises performing exactly two spectral measurements. ### Claim 3 (depends on 2) The determining method according to claim 2, wherein the phase shift values used for the two spectral measurements are 0 and π. ### Claim 4 (depends on 3) The determining method according to claim 3, comprising performing spectral measurements for two distinct perception positions and determining values assumed by the phase filter as a function of the frequency according to one or several of the following criteria: the value π for each frequency for which a phase shift of π causes an increase of the characteristic parameter for each perception position; the value 0 for each frequency for which a phase shift of π causes a decrease of the characteristic parameter for each perception position; the value π for each frequency for which a phase shift of π causes an increase of the characteristic parameter for one perception position without modifying the characteristic parameter for the other perception position significantly; and/or the value π for each frequency for which a phase shift of π causes, for a listening position, an increase above an increase threshold, for example +3 dB, of the characteristic parameter while causing, for the other perception position, a decrease below a decrease threshold, for example −3 dB, of the characteristic parameter. ### Claim 5 (depends on 3) The determining method according to claim 3, comprising performing spectral measurements for two distinct perception positions and determining values assumed by the phase filter as a function of the frequency according to one or several of the following criteria: the value π for each frequency for which a phase shift of π causes a decrease of the characteristic parameter for each perception position; the value 0 for each frequency for which a phase shift of π causes an increase of the characteristic parameter for each perception position; the value π for each frequency for which a phase shift of π causes a decrease of the characteristic parameter for one perception position without modifying the characteristic parameter for the other perception position significantly; and/or the value π for each frequency for which a phase shift of π causes, for a listening position, a decrease above a decrease threshold, for example −3 dB, of the characteristic parameter while causing, for the other perception position, an increase below an increase threshold, for example +3 dB, of the characteristic parameter. ### Claim 6 (depends on 3) The determining method according to claim 3, wherein the value of the phase difference between two transducers is chosen to be equal to the value of +n/2 or −π/2 for each frequency for which none of the aforementioned criteria are applicable. ### Claim 7 (depends on 2) The determining method according to claim 2, wherein the phase filter is determined by taking a phase shift of π for the frequencies for which a phase shift of π causes an increase, respectively a decrease, of the characteristic parameter, a nil phase shift for the frequencies for which a phase shift of π causes a decrease, respectively an increase, of the characteristic parameter, and a nil phase shift for the other frequencies. ### Claim 8 (depends on 1) The determining method according to claim 1, wherein the spectral measurements are done for each perception position with a series of phase shift values with a regular interval between the phase shift values. ### Claim 9 (depends on 7) The determining method according to claim 7, wherein the spectral measurements are done successively by varying the phase shift incrementally between the successive spectral measurements. ### Claim 10 (depends on 7) The determining method according to claim 7, wherein the step for performing spectral measurements comprises performing N measurements for each perception position, with an interval of 2π/N between the phase shift values, N being a real number. ### Claim 11 (depends on 1) The determining method according to claim 1, wherein the determination of the phase filter comprises the determination of the first phase filter, and the unwrapping and/or smoothening of the first phase filter. ### Claim 12 (depends on 1) The determining method according to claim 1, wherein the step for performing spectral measurements comprises performing spectral measurements for several distinct perception positions, and the step for determining the phase filter comprises determining a phase filter as an average of phase filters associated with the different perception positions. ### Claim 13 (depends on 1) The determining method according to claim 1, wherein the step for performing spectral measurements comprises performing spectral measurements for several distinct perception positions, and the determining step comprises determining a phase filter from the average of the spectral measurements associated with the different perception positions. ### Claim 14 (depends on 1) The determining method according to claim 1, wherein the characteristic parameter is the amplitude of the vibrations. ### Claim 15 (depends on 1) The determining method according to claim 1, wherein the vibrations are sound vibrations, the first transducer and the second transducer being electroacoustic transducers. ### Claim 16 (depends on 1) The determining method according to claim 1, wherein the vibrations are mechanical vibrations of a solid that are perceptible to the touch and/or capable of generating acoustic waves due to the vibrations of the solid. ### Claim 17 (depends on 1) A method for generating vibrations that are perceptible by a user using a system for generating vibrations comprising a source of electrical signals in order to supply a first electrical signal and a second electrical signal, a filtering module configured for the relative phase shift of the first electrical signal and the second electrical signal by implementing a phase filter determined according to a determining method according to claim 1, and generating vibrations via at least one pair of transducers comprising a first transducer and a second transducer respectively converting the first electrical signal and the second electrical signal, phase-shifted relative to one another by the filtering module, into vibrations. ### Claim 18 (depends on 1) A method for reproducing sounds using a stereophonic system comprising a signal source configured to supply a first audio signal and a second audio signal, a filtering module configured for the relative phase shift of the first audio signal and the second audio signal by implementing a phase filter determined according to a determining method according to claim 1, and the broadcasting of the first audio signal and the second audio signal filtered by the phase filter via a broadcasting assembly comprising at least one pair of electroacoustic transducers comprising a first electroacoustic transducer and a second electroacoustic transducer respectively broadcasting the first audio signal and the second audio signal phase-shifted relative to one another by the filtering module. ### Claim 19 (depends on 1) A filtering module for a vibration-generating system, in particular a stereophonic system, the filtering module being configured to implement a phase filter obtained by a determining method according to claim 1. ### Claim 20 (depends on 1) A system for generating vibrations comprising a source of electrical signals in order to supply a first electrical signal and a second electrical signal, a filtering module configured to implement a phase filter determined according to a determining method according to claim 1, and configured to introduce a relative phase shift between the first audio signal and the second audio signal, and at least one pair of transducers comprising a first transducer and a second transducer respectively receiving the first electrical signal and the second electrical signal, phase-shifted relative to one another by the phase filter. ### Claim 21 (depends on 1) A stereophonic system comprising a signal source configured to supply a first electrical audio signal and a second electrical audio signal, a filtering module configured for the relative phase shift of the first audio signal and the second audio signal by implementing a phase filter determined according to a determining method according to claim 1, and the broadcasting of the first audio signal and the second audio signal filtered by filtering module via a broadcasting assembly comprising at least one pair of electroacoustic transducers comprising a first electroacoustic transducer and a second electroacoustic transducer respectively broadcasting the first audio signal and the second audio signal phase-shifted relative to one another by the filtering module.