Abstract: A loudspeaker enclosure having a folded duct formed by an adjoining pair of the enclosure's panels and a pair of diagonally mounted internal panels. For example, at a lower left corner of the enclosure, a triangular first portion of the folded duct extends inward from a triangular hole in the front panel toward the back panel and is formed by the left panel, the bottom panel, and a first internal duct panel; and a trapezoidal second portion of the folded duct extends in the opposite direction and is formed by the left panel, the bottom panel, the first internal duct panel, and a second internal duct panel. The first internal duct panel is coupled to the front panel but ends short of the back panel to form the fold connecting the first and second portions of the folded duct, and the second internal duct panel is coupled to the back panel but ends short of the front panel to connect the folded duct with the enclosed air volume of the enclosure.

Abstract: An audio speaker driver having a voice coil with graduated windings such that different sections of the voice coil have different electrical resistances and/or lengths per unit of height of the voice coil. A center portion of the voice coil gives a greater BL, while outer portions give lower overall electrical resistance, such that the audio speaker driver is highly efficient and linear during low excursion operation, with a smoother transition from the linear region to the grossly non-linear region. The wire of the graduated voice coil can have varying cross-sectional area over its length, can be wound on varying on-center spacing, can be wound in different numbers of layers in the various sections, and/or it can fork into interlaced, parallel windings.

Abstract: An electromagnetic transducer such as an audio speaker, having a multi-gap geometry in which there are two or more magnetic air gaps over which magnetic flux flows in a same radial orientation. The magnetic flux is provided by one or more radially-charged magnets.

Abstract: An electromagnetic transducer such as an audio speaker having at least one of the soft magnetic components of its motor assembly constructed as a laminated structure of electrically insulated magnetically conductive sections. Eddy currents, which would have been induced in a monolithic component in response to an electrical signal applied to the voice coil, are prevented or significantly reduced by the electrical insulation material between the sections of the laminated component. The transducer produces less heat, is less susceptible to flux modulation, and has increased power handling and reduced distortion.

Abstract: A loudspeaker in which the voice coil diameter is so large that the voice coil is axially beneath the suspension roll of the surround. The surround has an overlapping suspension roll such that the inner portion of the surround is coupled to the diaphragm well inward of the bobbin. Such a transducer having greatly extended low frequency abilities by virtue of its wider, softer suspension roll enabling a much lower resonant frequency, and by virtue of its maximum sized magnet and voice coil yielding increased motor strength and power handling. Additionally, the dome diaphragm can now be vented through the portion of the dome that is beneath the surround roll, releasing the trapped back pressure below the diaphragm, thereby further lowering the resonant frequency.

Abstract: A loudspeaker cabinet with a laminated internal brace which has a first rigid layer coupled to a first exterior panel of the cabinet, a second rigid layer coupled to an a second exterior panel of the cabinet, and a damping layer affixed between the rigid layers where they overlap. Vibration, flexure, and expansion/contraction of the cabinet are damped by shearing forces applied to the damping layer as the rigid layers move in opposite, parallel directions.

Abstract: An electromagnetic transducer such as an audio speaker which includes an asymmetric diaphragm to deliver smooth frequency response with reduced distortion by reduction of common modes in the diaphragm. Other benefits such as asymmetric directivity patterns can be realized. The asymmetric cone has a perimeter OD at which a surround may be coupled, and an ID at which a bobbin or spacer may be coupled. The center of the ID is not coincident with the center of the OD. The transducer further includes a stabilization mechanism for reducing rocking of the diaphragm assembly. The stabilization mechanism may include mass balancing of the diaphragm and/or adjustments to the location or symmetry of the suspension components.

Abstract: An electromagnetic transducer such as an audio speaker, having a motor structure in which a shorting ring that sinks eddy currents also serves as a permanent fixture to provide coaxial alignment of two or more components within the transducer. These components could include various combinations of the yoke, the top plate, the magnet, and/or other parts. Ideally, the shorting ring extends axially as close as possible to the voice coil, to a position immediately adjacent the magnetic air gap.

Abstract: A thermally conductive chimney tube extends through a loudspeaker cabinet that encloses a volume of air heated by a speaker driver. The open ends of the chimney are outside the cabinet. A column of air within the chimney is in contact with the external ambient air, but sealed off from the enclosed volume of air. As the speaker driver heats the enclosed volume of air, the material of the chimney transfers the heat to the column of air, which rises and carries the heat away into the external ambient air, cooling the inside of the loudspeaker cabinet and thus cooling the speaker driver.

Abstract: An electromagnetic transducer such as an audio speaker which includes an asymmetric diaphragm to deliver smooth frequency response with reduced distortion by reduction of common modes in the diaphragm. Other benefits such as asymmetric directivity patterns can be realized. The asymmetric cone has a perimeter OD at which a surround may be coupled, and an ID at which a bobbin or spacer may be coupled. The center of the ID is not coincident with the center of the OD. The transducer further includes a stabilization mechanism for reducing rocking of the diaphragm assembly. The stabilization mechanism may include mass balancing of the diaphragm and/or adjustments to the location or symmetry of the suspension components.

Abstract: An electromagnetic transducer, such as an audio speaker, includes a return path member which is a pole piece for external magnet geometries or a cup for internal magnet geometries. The magnetic flux return path for the primary drive magnet is through a first portion of the return path member. A first section of a low reluctance magnetic flux return path for a secondary drive magnet is through a second portion of the return path member. A magnetically conductive plate provides a second section of the low reluctance return path from the second portion of the return path member to the secondary drive magnet.

Abstract: An acoustical transducer such as an audio loudspeaker or a microphone, having a suspension component whose outermost edge extends axially rather than radially and couples with an axial mounting surface in the transducer's frame rather than with a radial flat surface of the frame. The suspension component may be a surround or a spider. Eliminating the radial portions of the suspension component and the frame enables the use of a larger diaphragm within a transducer of unchanged outer dimensions, increasing the amount of air moved by or moving the diaphragm. It also enables closer on-center packing of multiple transducers onto the same baffle such as the front baffle of a speaker enclosure, or, put another way, it enables a higher percentage of the mounting baffle's front surface area to be covered with moving diaphragm area. Radial mounting flanges and their mounting holes are limited to portions of the frame which will not increase the gap space between adjacent transducers or other boundaries.

Abstract: An electromagnetic transducer such as an audio speaker, having an improved geometry in the positioning of its voice coils relative to its magnetic air gaps, facilitating a greater linear travel. The transducer has a push-pull geometry with at least two voice coils. At all positions throughout the linear travel region, less than 100% of the total voice coil windings are active, and less than 100% of the total available magnetic air gap height is active. As the voice coil assembly moves in one direction, the percentage of active windings or magnetic air gap is seamlessly handed off from the upper voice coil or magnetic air gap to the lower voice coil or magnetic air gap, and vice versa in the opposite direction. Some of the available voice coil windings and some of the available magnetic air gap height are left unused throughout the linear travel region, but, in exchange, the distance of the linear travel is dramatically increased.

Abstract: An electromagnetic transducer such as an audio speaker, having a push-push geometry in which there are two or more air gaps and the magnetic flux across the air gaps is in the same orientation. If there are more than one voice coil, the voice coils may thus be generating the same electromagnetic polarity by being wound in the same direction about the bobbin, or by being wound in opposite directions and having separate, opposite polarity electrical connections. The transducer exhibits high linearity over a long travel.

Abstract: An electromagnetic transducer, such as an audio speaker, includes a return path member which is a pole piece for external magnet geometries or a cup for internal magnet geometries. The magnetic flux return path for the primary drive magnet is through a first portion of the return path member. A first section of a low reluctance magnetic flux return path for a secondary drive magnet is through a second portion of the return path member. A magnetically conductive plate provides a second section of the low reluctance return path from the second portion of the return path member to the secondary drive magnet.

Abstract: An electromagnetic transducer such as an audio speaker exhibiting highly linear performance over a greatly extended excursion. The motor structure includes a stack of two or more magnet and plate pairs, with the magnets polarized in the same orientation such that the magnetic flux flows in the same direction over all of the magnetic air gaps. The voice coil is handed off from gap to gap with a configuration providing a substantially constant BL over an end-to-end distance at least as large as the thickness of one plate plus twice the thickness of one magnet.

Abstract: An acoustical transducer such as an audio loudspeaker or a microphone, having a suspension component whose outermost edge extends axially rather than radially and couples with an axial mounting surface in the transducer's frame rather than with a radial flat surface of the frame. The suspension component may be a surround or a spider. Eliminating the radial portions of the suspension component and the frame enables the use of a larger diaphragm within a transducer of unchanged outer dimensions, increasing the amount of air moved by or moving the diaphragm. It also enables closer on-center packing of multiple transducers onto the same baffle such as the front baffle of a speaker enclosure, or, put another way, it enables a higher percentage of the mounting baffle's front surface area to be covered with moving diaphragm area. Radial mounting flanges and their mounting holes are limited to portions of the frame which will not increase the gap space between adjacent transducers or other boundaries.

Abstract: An electromagnetic transducer such as an audio speaker, having a tube geometry motor which is not axisymmetric. The tube geometry motor includes a tubular yoke of soft magnetic material. The tube includes an air gap hole through a wall of the tube. A pole piece extends through the air gap hole to define the magnetic air gap between the tube wall and the pole piece. A hard magnet is coupled to the tube. In some embodiments, the pole piece is coupled to a back plate inside the tube, which in turn is coupled to the hard magnet. A diaphragm assembly is coupled to the outer side of the tube. The axis of movement of the diaphragm assembly and the extruded axis of the tube motor are perpendicular. Different models of the transducer motor can be fashioned by increasing the magnetic flux over the magnetic air gap, without having to make the motor wider or deeper, and without requiring new tooling for the tube, simply by making the motor longer and longer along the extruded axis.

Abstract: An electromagnetic transducer such as an audio speaker having at least one of the soft magnetic components of its motor assembly constructed as a laminated structure of electrically insulated magnetically conductive sections. Eddy currents, which would have been induced in a monolithic component in response to an electrical signal applied to the voice coil, are prevented or significantly reduced by the electrical insulation material between the sections of the laminated component. The transducer produces less heat, is less susceptible to flux modulation, and has increased power handling and reduced distortion.

Abstract: An electromagnetic transducer such as an audio speaker, having an improved geometry in the positioning of its voice coils relative to its magnetic air gaps, facilitating a greater linear travel. The transducer has a push-pull geometry with at least two voice coils. At all positions throughout the linear travel region, less than 100% of the total voice coil windings are active, and less than 100% of the total available magnetic air gap height is active. As the voice coil assembly moves in one direction, the percentage of active windings or magnetic air gap is seamlessly handed off from the upper voice coil or magnetic air gap to the lower voice coil or magnetic air gap, and vice versa in the opposite direction. Some of the available voice coil windings and some of the available magnetic air gap height are left unused throughout the linear travel region, but, in exchange, the distance of the linear travel is dramatically increased.