# US 12,003,941 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 12,003,941 B2 - Document ID: US12003941B2 - Status: Granted - Kind: B2 - Application number: 18/112,074 - Filed: 2023-02-21 - Published: 2023-06-29 - 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/US12003941B2 ## 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 is a radially polarized armature magnet, (v) the second magnetic negative spring portion comprises a first radially polarized ring magnet having a first polarity and a second radially polarized ring magnet having a second polarity, wherein the first radially polarized ring magnet and the second radially polarized ring magnet are oppositely polarized, and (vi) the first radially polarized ring magnet and the second radially polarized ring magnet are connected to a ferromagnetic element. ### 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 radially polarized ring magnet comprises an inner first radially polarized ring magnet and an outer first radially polarized ring magnet, wherein the inner first radially polarized ring magnet has a smaller radius than the outer first radially polarized ring magnet. ### Claim 14 (depends on 1) The loudspeaker of claim 1, wherein the second radially polarized ring magnet comprises an inner second radially polarized ring magnet and an outer second radially polarized ring magnet, wherein the inner second radially polarized ring magnet has a smaller radius than the outer second radially polarized ring magnet. ### Claim 15 (depends on 1) The loudspeaker of claim 1, wherein the armature permanent magnet comprises an array of arc-shaped elements. ### Claim 16 (depends on 1) The loudspeaker of claim 1, wherein the armature permanent magnet comprises a first armature permanent magnet and a second armature permanent magnet, wherein the first armature permanent magnet and the second armature permanent magnet are oppositely polarized. ### Claim 17 (depends on 16) The loudspeaker of claim 16, wherein (a) the first armature permanent magnet is repelled by the first radially polarized ring magnet and attracted to the second radially polarized ring magnet, (b) and the second armature permanent magnet is attracted to the first radially polarized ring magnet and repelled by the second radially polarized ring magnet. ### Claim 18 (depends on 1) The loudspeaker of claim 1 wherein the first radially polarized ring magnet, the second radially polarized ring magnet, and the ferromagnetic element form a closed magnetic circuit. ### Claim 19 (depends on 1) The loudspeaker of claim 1, wherein (a) the first radially polarized ring magnet comprises an inner first radially polarized ring magnet and an outer first radially polarized ring magnet, wherein the inner first radially polarized ring magnet has a smaller radius than the outer first radially polarized ring, (ii) the second radially polarized ring magnet comprises an inner second radially polarized ring magnet and an outer second radially polarized ring magnet, wherein the inner second radially polarized ring magnet has a smaller radius than the outer second radially polarized ring magnet; (iii) the ferromagnetic element comprises an outer ferromagnetic element and an inner ferromagnetic element, wherein (i) the outer ferromagnetic element connects the outer first radially polarized ring magnet and the outer second radially polarized ring magnet, and (ii) the inner ferromagnetic element connects the inner first radially polarized ring magnet and the inner second radially polarized ring magnet. ### Claim 20 (depends on 19) The loudspeaker of claim 19 wherein the inner first radially polarized ring magnet, the inner second radially polarized ring magnet, the inner ferromagnetic element, the outer first radially polarized ring magnet, the outer second radially polarized ring magnet and the outer ferromagnetic element form a closed magnetic circuit. ### Claim 21 (depends on 1) The loudspeaker of claim 1 wherein the magnetic negative spring produces a peak force of over 50 Newtons. ### Claim 22 (depends on 1) The loudspeaker of claim 1 wherein the magnetic negative spring produces a peak force of over 100 Newtons. ### Claim 23 (depends on 1) The loudspeaker of claim 1 wherein the magnetic negative spring produces a peak force of over 200 Newtons.