# US 12,003,942 B2 · Electroacoustic drivers and loudspeakers containing same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,003,942 B2 - Document ID: US12003942B2 - Status: Granted - Kind: B2 - Application number: 18/112,181 - Filed: 2023-02-21 - Published: 2023-06-22 - Granted: 2024-06-04 - Earliest claimed: 2020-01-21 - Assignees: Brane Audio, LLC - Applicants: Clean Energy Labs, LLC - Inventors: Joseph F. Pinkerton; David A. Badger; James A. Andrews; William Martin Lackowski; William Neil Everett - Web page: https://patentgrep.com/patent/US12003942B2 ## CPC - H04R 9/06: Loudspeakers - H04R 1/025: {Arrangements for fixing loudspeaker transducers, e.g. in a box, furniture} - H04R 1/2803: {for loudspeaker transducers} - H04R 3/00: Circuits for transducers (arrangements for producing a reverberation or echo sound G10K15/08; amplifiers H03F) - H04R 9/025: {Magnetic circuit} - H04R 9/041: {Centering} - H04R 9/046: {Construction} - H04R 11/02: Loudspeakers - H04R 17/00: Piezoelectric transducers; Electrostrictive transducers (piezoelectric or electrostrictive elements in general H10N30/00; details of piezoelectric or electrostrictive motors, generators or positioners {H10N30/00}) - H04R 29/001: {for loudspeakers (H04R29/007 takes precedence)} - H04R 29/003: {of the moving-coil type} - H04R 2400/07: Suspension between moving magnetic core and housing - 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 Electroacoustic drivers that can be utilized in loudspeaker systems that utilize drivers having a magnetic negative spring (MNS) (such as reluctance assist drivers (RAD) and permanent magnet crown (PMC) drivers). The electroacoustic drivers can be used at all audio frequencies, including subwoofer frequencies. The magnetic negative springs of the electroacoustic drivers can cancel, or partially cancel, the large pressure forces on a sound panel (of an audio speaker) so that substantial subwoofer notes can be efficiently and cost effectively produced in small/portable speakers. The electroacoustic drivers can include a stabilizing/centering mechanism to overcome the destabilizing forces of a MNS that are too large for a voice coil alone to produce. ## Claims ### Claim 1 A loudspeaker comprising: (a) an enclosure; (b) a sound panel mechanically connected to the enclosure; (c) a moveable armature mechanically connected to the sound panel comprising an actuator operable to convert electrical energy into mechanical energy, wherein the moveable armature is operable for moving the sound panel toward the enclosure to create a first air pressure force and away from the enclosure to create a second air pressure force; (d) a magnetic negative spring (MNS) that has a first magnetic negative spring portion that is mechanically connected to the moveable armature and a second magnetic negative spring portion that is stationary relative to the enclosure, wherein (i) the MNS is operable to provide a first magnetic negative spring force when the sound panel is moving toward the enclosure and a second magnetic negative spring force when the sound panel is moving away from the enclosure, (ii) the first magnetic negative spring force is oppositely directed to the first air pressure force, (iii) the second magnetic negative spring force is oppositely directed to the second air pressure force, (iv) the first magnetic negative spring portion comprises a first armature magnet and a second armature magnet, wherein the first armature magnet and the second armature magnet are oppositely polarized, (v) the second magnetic negative spring portion comprises a first ring magnet having a first polarity and a second ring magnet having a second polarity, wherein the first ring magnet and the second ring magnet are oppositely polarized; (vi) the first armature magnet is repelled by the first ring magnet and the second armature magnet is repelled by the second ring magnet when the sound panel is in a centered position. ### Claim 2 (depends on 1) The loudspeaker of claim 1, wherein the actuator is a voice coil. ### Claim 3 (depends on 2) The loudspeaker of claim 2, wherein the voice coil and the MNS share a same magnetic circuit. ### Claim 4 (depends on 1) The loudspeaker of claim 1, wherein the actuator is an electromagnet. ### Claim 5 (depends on 1) The loudspeaker of claim 1 further comprising a position sensor that senses the position of the sound panel. ### Claim 6 (depends on 5) The loudspeaker of claim 5, wherein the position sensor is an infrared position sensor. ### Claim 7 (depends on 1) The loudspeaker of claim 1 further comprising an armature centering mechanism. ### Claim 8 (depends on 7) The loudspeaker of claim 7, wherein the armature centering mechanism comprises a motor. ### Claim 9 (depends on 7) The loudspeaker of claim 7, wherein the armature centering mechanism comprises a gear motor. ### Claim 10 (depends on 7) The loudspeaker of claim 7, wherein the armature centering mechanism comprises an air pump. ### Claim 11 (depends on 1) The loudspeaker of claim 1 further comprising a flexible mechanical armature support. ### Claim 12 (depends on 7) The loudspeaker of claim 7, wherein the centering mechanism comprises a gear motor and an air pump. ### Claim 13 (depends on 1) The loudspeaker of claim 1, wherein the first ring magnet comprises an inner first ring magnet and an outer first ring magnet, wherein the inner first ring magnet has a smaller radius than the outer first ring magnet. ### Claim 14 (depends on 13) The loudspeaker of claim 13, wherein the second ring magnet comprises an inner second ring magnet and an outer second ring magnet, wherein the inner second ring magnet has a smaller radius than the outer second ring magnet. ### Claim 15 (depends on 14) The loudspeaker of claim 14, wherein the inner first ring magnet and inner second ring magnet are connected to a ferromagnetic element. ### Claim 16 (depends on 14) The loudspeaker of claim 14, wherein the outer first ring magnet and outer second ring magnet are connected to a ferromagnetic element. ### Claim 17 (depends on 1) The loudspeaker of claim 1, wherein (a) the first armature permanent magnet comprises a first array of arc-shaped elements, and (b) the second armature permanent magnet comprises a second array of arc-shaped elements. ### Claim 18 (depends on 1) The loudspeaker of claim 1 further comprises a ring of ferromagnetic material, wherein the first ring magnet and the second ring magnet are mechanically attached to the ring of ferromagnetic material. ### Claim 19 (depends on 1) The loudspeaker of claim 1 wherein the magnetic negative spring produces a peak force of over 50 Newtons. ### Claim 20 (depends on 1) The loudspeaker of claim 1 wherein the magnetic negative spring produces a peak force of over 100 Newtons. ### Claim 21 (depends on 1) The loudspeaker of claim 1 wherein the magnetic negative spring produces a peak force of over 200 Newtons. ### Claim 22 (depends on 1) The loudspeaker of claim 1, wherein (a) the moveable armature is operable for moving the sound panel toward the enclosure in a negative z-direction and away from the enclosure in a positive z-direction, and (b) when the sound panel is moved by the movable armature to a full negative z-direction, (i) the first armature magnet is repelled by the first ring magnet, (ii) the second armature magnet is repelled by the second ring magnet, and (iii) the second armature magnet is attracted by the first ring magnet. ### Claim 23 (depends on 1) The loudspeaker of claim 1, wherein (a) the moveable armature is operable for moving the sound panel toward the enclosure in a negative z-direction and away from the enclosure in a positive z-direction, and (b) when the sound panel is moved by the movable armature to a partial negative z-direction, (i) the first armature magnet is repelled by the first ring magnet, (ii) the second armature magnet is repelled by the second ring magnet, and (iii) the second armature magnet is attracted by the first ring magnet. ### Claim 24 (depends on 1) The loudspeaker of claim 1, wherein (a) the moveable armature is operable for moving the sound panel toward the enclosure in a negative z-direction and away from the enclosure in a positive z-direction, and (b) when the sound panel is moved by the movable armature to a partial positive z-direction, (i) the second armature magnet is repelled by the second ring magnet, (ii) the first armature magnet is repelled by the first ring magnet, and (iii) the first armature magnet is attracted by the second ring magnet. ### Claim 25 (depends on 1) The loudspeaker of claim 1, wherein (a) the moveable armature is operable for moving the sound panel toward the enclosure in a negative z-direction and away from the enclosure in a positive z-direction, and (b) when the sound panel is moved by the movable armature to a full positive z-direction, (i) the second armature magnet is repelled by the second ring magnet, (ii) the first armature magnet is repelled by the first ring magnet, and (iii) the first armature magnet is attracted by the second ring magnet. ### Claim 26 (depends on 1) The loudspeaker of claim 1, wherein (a) the moveable armature is operable for moving the sound panel toward the enclosure in a negative z-direction and away from the enclosure in a positive z-direction, and (b) the armature is radially stable in a full negative z-direction, a partial negative z-direction, a centered position, a partial positive z-direction, and a full positive z-direction. ### Claim 27 (depends on 1) The loudspeaker of claim 1, wherein average distance between the first armature magnet and second armature magnet is less than average distance between the first ring magnet and the second ring magnet.