Abstract: An electroacoustic transducer includes a first diaphragm, a first voice coil that is coupled to the first diaphragm, a second diaphragm, a second voice coil that is coupled to the second diaphragm, and a single common magnetic circuit that is configured to provide a magnetic field in both a first magnetic circuit gap and a separate second magnetic circuit gap. The first voice coil is located at least in part in the first magnetic circuit gap and the second voice coil is located at least in part in the second magnetic circuit gap.

Abstract: A semiconductor wafer has formed within it a plurality of piston tops of equal area. Each of the piston tops includes a thin flat region from which a majority of the thickness of the original semiconductor wafer may have been removed. A first one of the piston tops has a lower thickness than a second one of the piston tops. The second piston top has at least one hole in it, the volume of the hole corresponding to the difference in thickness between the first and second piston tops, such that the masses of the first and second piston tops differ by less than the variation in thickness between them.

Abstract: Various implementations include miniature loudspeaker drivers. In some aspects, an electro-acoustic driver includes: a cone having a surface area configured to radiate acoustic energy; a suspension coupled to the cone; and a support structure coupled to the suspension and having an outer linear dimension in a plane of the cone of approximately 6.0 millimeters (mm) or less, wherein the surface area of the cone is at least 49% of an overall cross-sectional area of the electro-acoustic driver in the plane of the cone.

Abstract: An active vibration isolation system for isolating a suspended platform from vibration input to the vibration isolation system base includes an exoskeleton, a rotary actuator, and a drive mechanism separate from the exoskeleton for providing force output from the rotary actuator to the suspended plant. The rotary actuator may include inner and outer rotors which rotate relative to each other. The rotary actuator may be free to translate relative to the vibration isolation system base and the suspended platform, and both the inner and outer rotors may be free to rotate relative to the exoskeleton.

Abstract: A semiconductor wafer has formed within it a plurality of piston tops of equal area. Each of the piston tops includes a thin flat region from which a majority of the thickness of the original semiconductor wafer may have been removed. A first one of the piston tops has a lower thickness than a second one of the piston tops. The second piston top has at least one hole in it, the volume of the hole corresponding to the difference in thickness between the first and second piston tops, such that the masses of the first and second piston tops differ by less than the variation in thickness between them.

Abstract: A diaphragm and suspension for an electroacoustic transducer are formed by depositing a layer of compliant material on a first surface of a solid substrate and removing material from a second surface of the solid substrate. The removal leaves a block of substrate material suspended within an inner perimeter of an outer support ring of the substrate material by the compliant material, the block providing the diaphragm.

Abstract: A diaphragm and suspension for an electroacoustic transducer are formed by depositing a layer of compliant material on a first surface of a solid substrate and removing material from a second surface of the solid substrate. The removal leaves a block of substrate material suspended within an inner perimeter of an outer support ring of the substrate material by the compliant material, the block providing the diaphragm.

Abstract: A solid piston having a closed shape is attached to a solid support surrounding the piston and corresponding in shape to the shape of the piston by a layer of compliant material adhered to a top surface of the piston and a top surface of the support. The layer of compliant material includes an open central area exposing the top surface of the piston through the open area. An assembly for an electroacoustic transducer includes a piston, which is an elliptical plate of silicon having a flat top surface and serving as the diaphragm, an elliptical support ring of silicon surrounding the piston and separated from the piston by a gap, and a layer of compliant material adhered to a top surface of the support ring and to the top surface of the piston, suspending the piston in the gap. An elliptical or cylindrical motor is coupled to the piston.

Abstract: An apparatus includes a frame and a surround element that couples a diaphragm to the frame such that the diaphragm is movable in a reciprocating manner relative to the frame. The surround element includes a half-roll element having a concave apparent area and a convex apparent area. The concave and the convex apparent areas are disproportionate. Another apparatus includes a diaphragm, a frame, and a surround element that couples the diaphragm to the frame such that the diaphragm is movable in a reciprocating manner relative to the frame. The surround element includes a half-roll element having a horizontal span and a free-length. A ratio of the horizontal span to the free-length is constant throughout the half-roll element. According to another example, an apparatus includes a landing and a half-roll element adjacent the landing. The half-roll element includes an inner portion, an outer portion having a variable thickness, and a transition portion located between the inner portion and the outer portion.

Abstract: An apparatus includes a frame and a surround element that couples a diaphragm to the frame such that the diaphragm is movable in a reciprocating manner relative to the frame. The surround element includes a half-roll element having a concave apparent area and a convex apparent area. The concave and the convex apparent areas are disproportionate. Another apparatus includes a diaphragm, a frame, and a surround element that couples the diaphragm to the frame such that the diaphragm is movable in a reciprocating manner relative to the frame. The surround element includes a half-roll element having a horizontal span and a free-length. A ratio of the horizontal span to the free-length is constant throughout the half-roll element. According to another example, an apparatus includes a landing and a half-roll element adjacent the landing. The half-roll element includes an inner portion, an outer portion having a variable thickness, and a transition portion located between the inner portion and the outer portion.

Abstract: A moving magnet motor with a stator comprising first and second spaced coil-wound cores that each have a width, the cores separated by an elongated gap, and an elongated magnet located at least in part in the gap and lying generally along a motor depth axis that is in the gap and is generally uniformly offset from the cores, where the magnet has poles. The motor has a width axis that is perpendicular to the depth axis and is generally uniformly offset from the cores. The magnet has a width along the motor width axis and the cores each have a width along the motor width axis. Along the motor depth axis the ratio of the width of the magnet or a pole of the magnet to the width of a core varies.

Abstract: A moving magnet motor with a stator comprising first and second spaced coil-wound cores that each have a width, the cores separated by an elongated gap, and an elongated magnet located at least in part in the gap and lying generally along a motor depth axis that is in the gap and is generally uniformly offset from the cores, where the magnet has poles. The motor has a width axis that is perpendicular to the depth axis and is generally uniformly offset from the cores. The magnet has a width along the motor width axis and the cores each have a width along the motor width axis. Along the motor depth axis the ratio of the width of the magnet or a pole of the magnet to the width of a core varies.

Abstract: An apparatus includes a lamination stack for a motor stator. The lamination stack comprises a plurality of conductive laminates. The laminates are coupled to each other in a stacking direction along a stacking axis. Each laminate comprises a base, a plurality of fins extending from a first side of the base, a plurality of spacings between the fins, a row of teeth extending from a second side of the base opposite the first side, each tooth constructed and arranged to communicate with windings of a conductive coil, and a plurality of spacings between the teeth. The lamination stack also comprises a plurality of first channels formed from the spacings between the fins and a plurality of second channels formed from the spacings between the teeth. The first and second channels extend along the stacking axis.

Abstract: A diaphragm and suspension for an electroacoustic transducer are formed by depositing a layer of compliant material on a first surface of a solid substrate and removing material from a second surface of the solid substrate. The removal leaves a block of substrate material suspended within an inner perimeter of an outer support ring of the substrate material by the compliant material, the block providing the diaphragm.

Abstract: An active vibration isolation system for isolating a suspended platform from vibration input to the vibration isolation system base includes an exoskeleton which supports the suspended platform relative to the base. The exoskeleton includes first and second scissors mechanisms with main links of unequal length. The main links pass through a parallel condition as the suspended platform moves over its intended range of travel relative to the base. The vibration isolation system may include a rotary actuator and a drive mechanism separate from the exoskeleton for providing force output from the rotary actuator to the suspended platform. The rotary actuator may include inner and outer rotors which rotate relative to each other and may be free to rotate relative to the exoskeleton. The rotary actuator may be free to translate relative to the vibration isolation system base and the suspended platform.

Abstract: An apparatus includes a lamination stack for a motor stator. The lamination stack comprises a plurality of conductive laminates. The laminates are coupled to each other in a stacking direction along a stacking axis. Each laminate comprises a base, a plurality of fins extending from a first side of the base, a plurality of spacings between the fins, a row of teeth extending from a second side of the base opposite the first side, each tooth constructed and arranged to communicate with windings of a conductive coil, and a plurality of spacings between the teeth. The lamination stack also comprises a plurality of first channels formed from the spacings between the fins and a plurality of second channels formed from the spacings between the teeth. The first and second channels extend along the stacking axis.

Abstract: An active vibration control device is provided that is configured to control the position of a body relative to a reference frame. The control device includes sensors that provide input signals corresponding to movement of the body in at least one direction, a rotary rotary actuator configured to control the position of the body, and four-bar linkage connecting the rotary rotary actuator to the body. The linkage converts the rotary motion output from the rotary actuator into a linear motion of the body. The controller, based on the input signals from the reference frame sensors, provides control signals to the rotary rotary actuator which acts through the linkage to position the body in the at least one direction relative to the position of the reference frame.

Abstract: An active vibration isolation system for isolating a suspended platform from vibration input to the vibration isolation system base includes an exoskeleton which supports the suspended platform relative to the base. The exoskeleton includes first and second scissors mechanisms with main links of unequal length. The main links pass through a parallel condition as the suspended platform moves over its intended range of travel relative to the base. The vibration isolation system may include a rotary actuator and a drive mechanism separate from the exoskeleton for providing force output from the rotary actuator to the suspended platform. The rotary actuator may include inner and outer rotors which rotate relative to each other and may be free to rotate relative to the exoskeleton. The rotary actuator may be free to translate relative to the vibration isolation system base and the suspended platform.

Abstract: An active vibration isolation system for isolating a suspended platform from vibration input to the vibration isolation system base includes an exoskeleton, a rotary actuator, and a drive mechanism separate from the exoskeleton for providing force output from the rotary actuator to the suspended plant. The rotary actuator may include inner and outer rotors which rotate relative to each other. The rotary actuator may be free to translate relative to the vibration isolation system base and the suspended platform, and both the inner and outer rotors may be free to rotate relative to the exoskeleton.

Abstract: An active vibration control device is provided that is configured to control the position of a body relative to a reference frame. The control device includes sensors that provide input signals corresponding to movement of the body in at least one direction, a rotary rotary actuator configured to control the position of the body, and four-bar linkage connecting the rotary rotary actuator to the body. The linkage converts the rotary motion output from the rotary actuator into a linear motion of the body. The controller, based on the input signals from the reference frame sensors, provides control signals to the rotary rotary actuator which acts through the linkage to position the body in the at least one direction relative to the position of the reference frame.