# US 10,771,915 B2 · Car stereo audio expanding method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,771,915 B2 - Document ID: US10771915B2 - Status: Granted - Kind: B2 - Application number: 16/614,371 - Filed: 2017-12-25 - Published: 2020-03-12 - Granted: 2020-09-08 - Earliest claimed: 2017-09-30 - Applicants: Huizhou Desay SV Automotive Co., Ltd. - Inventors: Huixiong Yu - Web page: https://patentgrep.com/patent/US10771915B2 ## CPC - H04S 7/307: {Frequency adjustment, e.g. tone control (H04S7/301 takes precedence)} - B60R 11/0217: {for loud-speakers} - H04R 3/04: for correcting frequency response - H04R 3/12: for distributing signals to two or more loudspeakers {(specially adapted for hearing aids H04R25/407)} - 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)} - H04R 2499/13: Acoustic transducers and sound field adaptation in vehicles - H04S: STEREOPHONIC SYSTEMS - B60R: VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, 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) ## Abstract The present invention relates to the technical field of a car stereo audio expanding method. The method performs delay processing on sound channel signals in a loudspeaker twice to counteract signals reflected by door glass, such that the sound field performs better. The sound field processing method of the present invention can enable the sound field of sounds heard by the driver to be centered and the diffusion of both sides to be symmetric. Also the sound field can be expanded to the outside of the vehicle, resolving the problem that the car audio, in a car environment, has a sound field weighted toward one side, has a narrow sound field width, and has poor hearing effects due to the confined sound field. The invention enables sound heard to be authentic rather than empty. ## Claims ### Claim 1 A car stereo audio expanding method, comprising steps of: S10, performing different degrees of first delay processing on a first sound channel signal output to a first loudspeaker near a driving seat and a second sound channel signal output to a second loudspeaker far from the driving seat according to a relative position; S20, outputting the first sound channel signal processed by the first delay to a first sound mixer, and performing a second delay processing on the first sound channel signal according to a relative position and outputting to a second sound mixer; outputting the second sound channel signal processed by the first delay to the second sound mixer, and performing the second delay processing on the second sound channel signal according to a relative position and outputting to the first sound mixer; S30, after performing reverse operation to the second sound channel signal processed by the second delay, adding it to the first sound channel signal output to the first sound mixer to obtain a sound channel signal for driving the first loudspeaker; after performing reverse operation to the first sound channel signal processed by the second delay, adding it to the second sound channel signal output to the second sound mixer to obtain a sound channel signal for driving the second loudspeaker. ### Claim 2 (depends on 1) The car stereo audio expanding method according to claim 1, characterized in that in the step S10, the performing a first delay processing on a first sound channel signal and a second sound channel signal includes setting delay time of a first delay timer for the first loudspeaker and the second loudspeaker, respectively. ### Claim 3 (depends on 2) The car stereo audio expanding method according to claim 2, characterized in that the delay time of the first delayer of the first loudspeaker is calculated by using the following formula: T11=L/V+T21; wherein T11 represents the delay time of the first delay timer of the first loudspeaker, T21 represents the delay time of the first delay timer of the second loudspeaker, and the unit is second (s); L represents a difference between a direct sound path from the first sound channel signal and a direct sound path from the second sound channel signal to the driving seat, and the unit is meter (m); V represents a velocity of sound in air. ### Claim 4 (depends on 2) The car stereo audio expanding method according to claim 2, characterized by setting the delay time T21 of the first delay timer for the second loudspeaker as 0. ### Claim 5 (depends on 3) The car stereo audio expanding method according to claim 3, characterized by setting the delay time T21 of the first delay timer for the second loudspeaker as 0. ### Claim 6 (depends on 1) The car stereo audio expanding method according to claim 1, characterized in that in the step S20, the performing second delay processing on a first sound channel signal and a second sound channel signal includes setting delay timer of a second delay timer for the first loudspeaker and the second loudspeaker, respectively. ### Claim 7 (depends on 6) The car stereo audio expanding method according to claim 6, characterized in that the delay time of the second delay timer for the first loudspeaker is calculated by using the following formula: T12=(Lr1+Lr2−Ld)/V; wherein T12 represents the delay time of the second delay timer for the first loudspeaker, and the unit is second (s); Lr1 represents a first path of a reflection sound of the first sound channel signal; Lr2 represents a second path of a reflection sound of the first sound channel signal; Ld represents a direct sound path of the first sound channel signal; V represents a velocity of sound in air. ### Claim 8 (depends on 6) The car stereo audio expanding method according to claim 6, characterized in that the delay time of the second delay timer for the second loudspeaker is calculated by using the following formula: T22=(Rr1+Rr2−Rd)/V; wherein T22 represents the delay time of the second delay timer for the second loudspeaker, the unit is second (s); Rr1 represents a first path of a reflection sound of the second sound channel signal; Rr2 represents a second path of a reflection sound of the second sound channel signal; Rd represents a direct sound path of the second sound channel signal; V represents a velocity of sound in air. ### Claim 9 (depends on 1) The car stereo audio expanding method according to claim 1, characterized in that in the step S20, before performing second delay processing on a first sound channel signal and a second sound channel signal, filtering processing should be performed, respectively. ### Claim 10 (depends on 9) The car stereo audio expanding method according to claim 9, characterized in that the filtering processing includes using a filter to filter a low frequency signal that is not obvious in direction and a high frequency signal that are not sensitive to phase. ### Claim 11 (depends on 1) The car stereo audio expanding method according to claim 1, characterized in that the first loudspeaker is a left loudspeaker and the second loudspeaker is a right loudspeaker.