# US 2019/0246228 A1 · Method and apparatus for controlling acoustic signals to be recorded and/or reproduced by an electro-acoustical sound system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0246228 A1 - Document ID: US20190246228A1 - Status: Published application - Kind: A1 - Application number: 16/388,592 - Filed: 2019-04-18 - Published: 2019-08-08 - Earliest claimed: 2016-10-19 - Assignees: Huawei Technologies Co., Ltd.; University of Parma - Applicants: Huawei Technologies Co., Ltd.; University of Parma - Inventors: Simone FONTANA; Angelo FARINA - Web page: https://patentgrep.com/patent/US20190246228A1 ## CPC - H04S 7/301: {Automatic calibration of stereophonic sound system, e.g. with test microphone} - H04R 29/001: {for loudspeakers (H04R29/007 takes precedence)} - H04R 2499/13: Acoustic transducers and sound field adaptation in vehicles - H04S 2400/01: Multi-channel, i.e. more than two input channels, sound reproduction with two speakers wherein the multi-channel information is substantially preserved - H04S 2400/15: Aspects of sound capture and related signal processing for recording or reproduction - 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 The present invention relates to a method and to an apparatus, both arranged for controlling acoustic signals to be recorded or reproduced by an electro-acoustical sound system. For this purpose: an initial digital filter is determined by solving an inverse problem, wherein the initial digital filter is configured to control acoustic signals to be recorded and/or reproduced by the electro-acoustical sound system; a frequency-dependent articulation parameter is determined by executing a time spectral psychoacoustic automatic audio quality test on the initial digital filter; a frequency-dependent regularization parameter, used for determining the initial digital filter, is tuned by use of the frequency-dependent articulation parameter; and, by use of the tuned frequency-dependent regularization parameter, a digital filter configured to control acoustic signals to be recorded or reproduced by the electro-acoustical sound system is determined. ## Claims ### Claim 1 A method for controlling acoustic signals to be recorded and/or reproduced by an electro-acoustical sound system, wherein the method comprises the following steps: determining an initial digital filter by solving an inverse problem, wherein the initial digital filter is configured to control acoustic signals to be recorded and/or reproduced by the electro-acoustical sound system; determining a frequency-dependent articulation parameter by executing a time spectral psychoacoustic automatic audio quality test on the initial digital filter; tuning a frequency-dependent regularization parameter, used for determining the initial digital filter, by use of the frequency-dependent articulation parameter; and determining, by use of the tuned frequency-dependent regularization parameter, a digital filter configured to control acoustic signals to be recorded and/or reproduced by the electro-acoustical sound system. ### Claim 2 (depends on 1) The method according to claim 1, wherein the determining of the frequency-dependent articulation parameter by executing the audio quality test to the initial digital filter comprises: executing a convolution of the initial digital filter with an acoustic test signal; and determining the frequency-dependent articulation parameter by determining a level of decay after a predetermined time interval between two consecutive bursts of the acoustic test signal. ### Claim 3 (depends on 2) The method according to claim 2, wherein the acoustic test signal comprises a repetition of bursts. ### Claim 4 (depends on 1) The method according to claim 1, wherein the initial digital filter is determined by determining a least square solution to the inverse problem. ### Claim 5 (depends on 1) The method according to claim 1, wherein the tuned frequency-dependent regularization parameter is, up to an offset, a decreasing function of the articulation, the offset including a frequency-dependent regularization parameter determined when executing the determining of the initial digital filter. ### Claim 6 (depends on 1) The method according to claim 1, wherein the frequency-dependent regularization parameter is tuned as follows: β k = β Nelson , k + ( β 0 + β 1 Art k ) , wherein k denotes a k-th frequency index, wherein β0 and β1 are pre-set frequency-dependent regularization constants, wherein Artk is the frequency-dependent articulation parameter, and wherein βNelson,k is the frequency-dependent regularization parameter employed when executing the determining of the initial digital filter. ### Claim 7 (depends on 1) The method according to claim 1, wherein the initial digital filter is an equalizing filter. ### Claim 8 An apparatus configured to control acoustic signals to be recorded and/or reproduced by an electro-acoustical sound system, wherein the apparatus comprises: an initial digital filter determining entity configured to determine an initial digital filter by solving an inverse problem, wherein the initial digital filter is configured to control acoustic signals to be recorded and/or reproduced by the electro-acoustical sound system; a frequency-dependent articulation parameter determining entity configured to determine a frequency-dependent articulation parameter by executing a time spectral psychoacoustic automatic audio quality test on the initial digital filter; a frequency-dependent regularization parameter tuning entity configured to tune a frequency-dependent regularization parameter, used for determining the initial digital filter, by use of the frequency-dependent articulation parameter; and a digital filter determining entity configured to determine, by use of the tuned frequency-dependent regularization parameter, a digital filter configured to control acoustic signals to be recorded and/or reproduced by the electro-acoustical sound system. ### Claim 9 (depends on 8) The apparatus according to claim 8, wherein the frequency-dependent articulation parameter determining entity is configured to: execute a convolution of the initial digital filter with an acoustic test signal; and determine the frequency-dependent articulation parameter by determining a level of decay after a predetermined time interval between two consecutive bursts of the acoustic test signal. ### Claim 10 (depends on 9) The apparatus according to claim 9, wherein the acoustic test signal comprises a repetition of bursts. ### Claim 11 (depends on 8) The apparatus according to claim 8, wherein the initial digital filter determining entity is configured to determine the initial digital filter by determining a least square solution to the inverse problem. ### Claim 12 (depends on 8) The apparatus according to claim 8, wherein the tuned frequency-dependent regularization parameter is, up to an offset, a decreasing function of the atriculation, the offset including a frequency-dependent regularization parameter determined when executing the determining of the initial digital filter. ### Claim 13 (depends on 8) The apparatus according to claim 8, wherein the frequency-dependent regularization parameter tuning entity is configured to tune the frequency-dependent regularization parameter as follows: β k = β Nelson , k + ( β 0 + β 1 Art k ) , wherein k denotes a k-th frequency index, wherein β0 and β1 are pre-set frequency-dependent regularization constants, wherein Artk is the frequency-dependent articulation parameter, and wherein βNelson,k is the frequency-dependent regularization parameter employed when executing the determining of the initial digital filter. ### Claim 14 (depends on 8) The apparatus according to claim 8, wherein the initial digital filter is an equalizing filter. ### Claim 15 (depends on 8) The apparatus according to claim 8, wherein the apparatus is an equalizer or beamformer. ### Claim 16 (depends on 1) A computer program product comprising computer readable program code that is configured to cause a computing device to execute steps of the method according to claim 1. ### Claim 17 (depends on 1) A computer-readable recording medium configured to store therein a computer program product, which comprises a computer readable program code that is configured to cause a computing device to execute steps of the method according to claim 1.