# US 10,872,591 B2 · Compensation means for a loudspeaker system and loudspeaker system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,872,591 B2 - Document ID: US10872591B2 - Status: Granted - Kind: B2 - Application number: 16/246,088 - Filed: 2019-01-11 - Published: 2019-05-16 - Granted: 2020-12-22 - Earliest claimed: 2016-07-13 - Assignees: Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V. - Applicants: Fraunhofer-Gesellschaft zur Foerderung der angewandten Forschung e.V. - Inventors: Lorenz Betz; Maximilian Wolf - Web page: https://patentgrep.com/patent/US10872591B2 ## CPC - G10K 11/178: by electro-acoustically regenerating the original acoustic waves in anti-phase - H04R 1/2834: {for loudspeaker transducers} - H04R 1/403: {loud-speakers} - H04S 7/301: {Automatic calibration of stereophonic sound system, e.g. with test microphone} - G10K 2210/1053: Hi-fi, i.e. anything involving music, radios or loudspeakers - H04R 2201/403: Linear arrays of transducers - H04S 2400/11: Positioning of individual sound objects, e.g. moving airplane, within a sound field (H04S2420/13 takes precedence) - G10K: SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR - 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) - H04S: STEREOPHONIC SYSTEMS ## Abstract Embodiments provide a compensator for a loudspeaker system having a first loudspeaker group having at least one sound transducer, the first loudspeaker group being configured to generate a first sound signal based on an audio signal, the sound signal having a useful signal portion and a distortion signal portion. The compensator has a second loudspeaker group having at least one sound transducer, the second loudspeaker group being configured to generate a second sound signal based on a compensation signal, the second sound signal compensating and/or reducing the distortion signal portion when superimposed with the first sound signal. ## Claims ### Claim 1 A compensator for a loudspeaker system comprising a first loudspeaker group comprising at least one sound transducer, the first loudspeaker group being configured to generate a first sound signal based on an audio signal, the first sound signal comprising a useful signal portion and a distortion signal portion, the compensator comprising: a second loudspeaker group comprising at least one sound transducer, the second loudspeaker group being configured to generate a second sound signal based on a compensation signal, the second sound signal compensating and/or reducing the distortion signal portion when superimposed with the first sound signal; wherein the compensator comprises a calculating unit comprising a signal synthesizer configured to generate the compensation signal starting from information on the distortion signal portion; and wherein the calculating unit comprises a signal analyzer configured to analyze the first sound signal relative to the useful signal portion and the distortion signal portion and to extract the information on the distortion signal portion; wherein the signal synthesizer is configured to invert the extracted distortion signal portion in order to acquire the compensation signal. ### Claim 2 A loudspeaker system comprising: a first loudspeaker group comprising at least one sound transducer, the first loudspeaker group being configured to generate a first sound signal based on an audio signal, the first sound signal comprising a useful signal portion and a distortion signal portion; and a second loudspeaker group comprising at least one sound transducer, the second loudspeaker group being configured to generate a second sound signal based on a compensation signal, the second sound signal compensating and/or reducing the distortion signal portion when superimposed with the first sound signal; wherein the loudspeaker system comprises a calculating unit comprising a signal synthesizer configured to generate the compensation signal starting from information on the distortion signal portion; and wherein the calculating unit comprises a signal analyzer configured to analyze the first sound signal relative to the useful signal portion and the distortion signal portion and to extract the information on the distortion signal portion; wherein the signal synthesizer is configured to invert the extracted distortion signal portion in order to acquire the compensation signal. ### Claim 3 (depends on 2) The loudspeaker system in accordance with claim 2, wherein superpositioning of the second sound signal and the first sound signal takes place in a sound field generated in space. ### Claim 4 (depends on 2) The loudspeaker system in accordance with claim 2, wherein the at least one sound transducer of the second loudspeaker group or the second loudspeaker group is oriented relative to a sound field of the first loudspeaker group or a listening position belonging to the first loudspeaker group. ### Claim 5 (depends on 2) The loudspeaker system in accordance with claim 2, wherein the first loudspeaker group comprises at least one passive sound transducer. ### Claim 6 (depends on 2) The loudspeaker system in accordance with claim 2, wherein the first loudspeaker group comprises a plurality of independent sound transducers for reproducing a stereo sound field and/or a surround sound field. ### Claim 7 (depends on 3) The loudspeaker system in accordance with claim 3, wherein the first loudspeaker group is spaced apart from the second loudspeaker group at a distance of at most 3 m or, advantageously, at most 1 m so that superpositioning takes place in the nearfield of the first loudspeaker group. ### Claim 8 (depends on 2) The loudspeaker system in accordance with claim 2, wherein the signal analyzer for analyzing receives the audio signal and compares the same to the first sound signal. ### Claim 9 (depends on 2) The loudspeaker system in accordance with claim 2, wherein the information on the distortion signal portion comprises the distortion signal portion isolated from the useful signal portion. ### Claim 10 (depends on 2) The loudspeaker system in accordance with claim 2, wherein the signal synthesizer is configured to determine the compensation signal while considering the transfer function of the at least one sound transducer of the second loudspeaker group. ### Claim 11 (depends on 2) The loudspeaker system in accordance with claim 2, wherein the signal analyzer comprises a measurer for measuring the acceleration, velocity and/or deflection of the membrane or a measurer for measuring the air-borne or structure-borne sound and/or a microphone and/or a processor for electrical measurements at the loudspeaker terminals. ### Claim 12 (depends on 2) The loudspeaker system in accordance with claim 2, wherein the signal analyzer comprises a processor for modeling and simulating the useful signal portion and distortion signal portion. ### Claim 13 (depends on 2) The loudspeaker system in accordance with claim 2, wherein the second loudspeaker group comprises a plurality of independent sound transducers and is configured to emit the second sound signal by means of beamforming. ### Claim 14 (depends on 2) The loudspeaker system in accordance with claim 2, wherein the second loudspeaker group comprises a plurality of independent sound transducers and is configured to generate several second sound signals for several sound fields. ### Claim 15 A calculating unit comprising a signal synthesizer, wherein the signal synthesizer is configured to determine a compensation signal starting from information on a distortion signal portion which, together with a useful signal portion is comprised by a first sound signal generated by a first loudspeaker group on the basis of an audio signal, wherein the compensation signal is suitable to compensate and/or reduce the distortion signal portion when outputting the same as a second sound signal via a second loudspeaker group by superpositioning with the first sound signal; wherein the signal synthesizer is configured to generate the compensation signal starting from information on the distortion signal portion; and wherein the calculating unit comprises a signal analyzer configured to analyze the first sound signal relative to the useful signal portion and the distortion signal portion and to extract the information on the distortion signal portion; wherein the signal synthesizer is configured to invert the extracted distortion signal portion in order to acquire the compensation signal. ### Claim 16 A method for generating a useful signal portion, comprising: outputting, using a first loudspeaker group comprising at least one sound transducer, a first sound signal based on an audio output signal, the first sound signal comprising a useful signal portion and a distortion signal portion; determining a compensation signal starting from information on a distortion signal portion which, together with a useful signal portion, is comprised by a first sound signal; and outputting, using a second loudspeaker group comprising at least one sound transducer, a second sound signal based on the compensation signal, the second sound signal compensating and/or reducing the distortion signal portion when superimposed with the first sound signal; wherein determining comprises generating the compensation signal starting from information on the distortion signal portion, analyzing the first sound signal relative to the useful signal portion and the distortion signal portion, extracting the information on the distortion signal portion and inverting the extracted distortion signal portion in order to acquire the compensation signal. ### Claim 17 A method for calculating a compensation signal, comprising: determining a compensation signal starting from information on a distortion signal portion which, together with a useful signal portion, is comprised by a first sound signal generated by a first loudspeaker group on the basis of an audio signal; and compensating and/or reducing the distortion signal portion when outputting the compensation signal as a second sound signal via a second loudspeaker group by superpositioning with the first sound signal; wherein determining comprises generating the compensation signal starting from information on the distortion signal portion, analyzing the first sound signal relative to the useful signal portion and the distortion signal portion, extracting the information on the distortion signal portion and inverting the extracted distortion signal portion in order to acquire the compensation signal. ### Claim 18 A non-transitory digital storage medium having stored thereon a computer program for performing a method for generating a useful signal portion, comprising: outputting, using a first loudspeaker group comprising at least one sound transducer, a first sound signal based on an audio output signal, the first sound signal comprising a useful signal portion and a distortion signal portion; determining a compensation signal starting from information on a distortion signal portion which, together with a useful signal portion, is comprised by a first sound signal; and outputting, using a second loudspeaker group comprising at least one sound transducer, a second sound signal based on the compensation signal, the second sound signal compensating and/or reducing the distortion signal portion when superimposed with the first sound signal; wherein determining comprises generating the compensation signal starting from information on the distortion signal portion, analyzing the first sound signal relative to the useful signal portion and the distortion signal portion, extracting the information on the distortion signal portion and inverting the extracted distortion signal portion in order to acquire the compensation signal; when said computer program is run by a computer. ### Claim 19 A non-transitory digital storage medium having stored thereon a computer program for performing a method for calculating a compensation signal, comprising: determining a compensation signal starting from information on a distortion signal portion which, together with a useful signal portion, is comprised by a first sound signal generated by a first loudspeaker group on the basis of an audio signal; and compensating and/or reducing the distortion signal portion when outputting the compensation signal as a second sound signal via a second loudspeaker group by superpositioning with the first sound signal; wherein determining comprises generating the compensation signal starting from information on the distortion signal portion, analyzing the first sound signal relative to the useful signal portion and the distortion signal portion, extracting the information on the distortion signal portion and inverting the extracted distortion signal portion in order to acquire the compensation signal; when said computer program is run by a computer.