# US 10,484,774 B2 · Acoustic transducer > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,484,774 B2 - Document ID: US10484774B2 - Status: Granted - Kind: B2 - Application number: 16/135,223 - Filed: 2018-09-19 - Published: 2019-01-17 - Granted: 2019-11-19 - Earliest claimed: 2016-12-11 - Assignees: Bose Corporation - Applicants: Bose Corporation - Inventors: Jason Silver; Roman Litovsky - Web page: https://patentgrep.com/patent/US10484774B2 ## CPC - H04R 1/1008: {Earpieces of the supra-aural or circum-aural type} - H04R 1/1075: {Mountings of transducers in earphones or headphones} - H04R 1/1091: {Details not provided for in groups H04R1/1008 - H04R1/1083} - H04R 1/2834: {for loudspeaker transducers} - H04R 1/2857: {for loudspeaker transducers} - H04R 1/347: {for obtaining a phase-shift between the front and back acoustic wave} - H04R 1/2888: {for loudspeaker transducers} - H04R 1/38: in which sound waves act upon both sides of a diaphragm and incorporating acoustic phase-shifting means, e.g. pressure-gradient microphone - 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 An acoustic transducer with an acoustic element that emits or receives front-side acoustic radiation from its front side, and emits or receives rear-side acoustic radiation from its rear side. A housing directs the front-side acoustic radiation and the rear-side acoustic radiation. A plurality of sound-conducting vents in the housing allow sound to enter the housing or allow sound to leave the housing. A distance between vents defines an effective length of an acoustic dipole. The housing and its vents are constructed and arranged such that the effective dipole length is frequency dependent. ## Claims ### Claim 1 A loudspeaker, comprising: first and second acoustic drivers that each emit front-side acoustic radiation from a front side of the driver and rear-side acoustic radiation from a rear side of the driver; a housing that comprises a rear acoustic volume that receives the rear-side acoustic radiation of both drivers and a front acoustic volume that receives the front-side acoustic radiation of a driver; a plurality of sound-emitting openings in the housing, wherein a distance between sound-emitting openings defines an effective length of a loudspeaker dipole, and wherein the housing and its sound-emitting openings are constructed and arranged such that the effective dipole length is frequency dependent wherein the effective dipole length is larger at lower frequencies than it is at higher frequencies; wherein first and second rear sound-emitting openings are acoustically coupled to the rear acoustic volume and wherein first and second front sound-emitting openings are acoustically coupled to the front acoustic volume, wherein the first rear sound-emitting opening is closer to the first front sound-emitting opening than is the second rear sound-emitting opening; a resistive screen covering the first rear sound-emitting opening; and an acoustic transmission line that is acoustically coupled to the rear acoustic volume and comprises the second rear sound-emitting opening. ### Claim 2 (depends on 1) The loudspeaker of claim 1, further comprising a structure for wearing the loudspeaker on a user's head, wherein the drivers are held near but not covering an ear of the user when the loudspeaker is worn on the user's head. ### Claim 3 A loudspeaker, comprising: a housing with an interior; first and second acoustic drivers in the housing interior, wherein the first and second acoustic drivers each emit front-side acoustic radiation from a front side of the driver into a front volume of the housing, and rear-side acoustic radiation from a rear side of the driver into a rear volume of the housing; a plurality of sound-emitting openings in the housing, the openings comprising a first front opening that is configured to emit front-side sound, a first rear opening that is configured to emit rear-side sound, and a second rear opening that is configured to emit rear-side sound; wherein a first loudspeaker dipole is defined by the first front opening and the first rear opening, and a second loudspeaker dipole is defined by the first front opening and the second rear opening; wherein the first rear opening is closer to the first front opening than is the second rear opening, so that the first loudspeaker dipole has a shorter effective length than does the second loudspeaker dipole; and a structure that carries the housing, wherein the structure is configured to be worn by a user such that the housing is not on or in the user's ear, and with the first front opening closer to the ear canal opening than the first and second rear openings, and the first rear opening closer to the ear canal opening than the second rear opening. ### Claim 4 (depends on 3) The loudspeaker of claim 3, wherein the effective dipole length is larger at lower frequencies than it is at higher frequencies. ### Claim 5 (depends on 3) The loudspeaker of claim 3, further comprising a resistive screen covering a sound-emitting opening. ### Claim 6 (depends on 3) The loudspeaker of claim 3, wherein a sound-emitting opening comprises a port opening. ### Claim 7 (depends on 3) The loudspeaker of claim 3, wherein the housing comprises a rear acoustic volume that receives the rear-side acoustic radiation of both drivers. ### Claim 8 (depends on 7) The loudspeaker of claim 7, wherein first and second rear sound-emitting openings are acoustically coupled to the rear acoustic volume. ### Claim 9 (depends on 8) The loudspeaker of claim 8, further comprising a resistive screen covering the first rear sound-emitting opening. ### Claim 10 (depends on 8) The loudspeaker of claim 8, further comprising an acoustic transmission line that is acoustically coupled to the rear acoustic volume and comprises the second rear sound-emitting opening. ### Claim 11 (depends on 10) The loudspeaker of claim 10, wherein a front sound-emitting opening receives front-side acoustic radiation, and wherein the first rear sound-emitting opening is closer to the front sound-emitting opening than is the second rear sound-emitting opening. ### Claim 12 (depends on 7) The loudspeaker of claim 7, further comprising an acoustic transmission line that is acoustically coupled to the rear acoustic volume and comprises the second rear sound-emitting opening. ### Claim 13 (depends on 3) The loudspeaker of claim 3, wherein the housing comprises a front acoustic volume that receives the front-side acoustic radiation of a driver. ### Claim 14 (depends on 13) The loudspeaker of claim 13, wherein first and second front sound-emitting openings are acoustically coupled to the front acoustic volume. ### Claim 15 (depends on 14) The loudspeaker of claim 14, further comprising a resistive screen covering one of the first and second front sound-emitting openings. ### Claim 16 (depends on 3) The loudspeaker of claim 3, further comprising wherein the structure that carries the housing is configured to be worn on a user's head, wherein the drivers are held near but not covering an ear of the user when the loudspeaker is worn on the user's head.