Abstract: A muzzle device is provided comprising a cylindrical body defining a device axis. The body having a rear end with an attachment facility configured to connect to a firearm barrel muzzle and a forward end. The body defines a bore extending along the device axis, and further the body defines a plurality of enclosed voids.

Abstract: An electromagnetic transducer, such as an audio loudspeaker, having an underhung voice coil disposed in a magnetically tapered air gap. The taper provides asymmetry in the magnetic flux field. As the voice coil moves in one direction, the motor becomes stronger and more efficient, and as the voice coil moves in the other direction, the motor becomes weaker and less efficient. This results in an increase in even-order harmonics. The magnetic taper may result from a geometric taper of one or both of the opposing steel pieces which form the gap, or it may result from one or both of them having an at least partially laminated structure. The geometric taper provides a magnetic reluctance gradient along the height of the magnetic air gap. The laminated structure provides a magnetic reluctance gradient through the thickness of the laminated member (e.g. top plate). The magnetic reluctance gradient produces a magnetic flux density gradient along the height of the magnetic air gap.

Abstract: An electromagnetic transducer such as an audio speaker, having three or more voice coils disposed in one or more magnetic air gaps. The voice coils can be combined in any permutation of series/parallel connections, to select any one of a predetermined set of impedance values for the transducer. Optionally, the transducer is equipped with a set of different terminal connector plugs, each of which automatically performs the series/parallel connections for its designated impedance value. All voice coils may be selected as active, allowing for a constant maximum efficiency, regardless of which impedance option is selected.

Abstract: An A/V system in which the user can set up a “virtual television channel” which includes the video from one channel and the audio from another channel. The virtual channel is included in the on-screen programming guide, and is user-selectable for viewing or recording just like the actual channels. The user may use a virtual channel to get the 5.1 surround audio from an HD broadcast with the video from an SD simulcast, or to include one football game's audio content with two football games' video content for an improved pip capability, or to get classical music with a stock ticker video, and so forth.

Abstract: One or two thermally conductive chimney tubes extend through a loudspeaker cabinet that encloses a volume of air heated by a speaker driver. The open ends of each chimney are outside the cabinet. A column of air within each 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. A second chimney can be oriented perpendicular to the first, ensuring that one of them is vertical regardless of cabinet orientation. A single chimney can be oriented diagonally, ensuring some chimney effect regardless of cabinet orientation.

Abstract: A television set, set-top box, or the like, which finds a corresponding HD program when a user selects an SD program for viewing or recording, and which gives the user a visual prompt enabling him to select the HD program instead. The HD channel is inserted into the same on-screen programming guide page as the SD channel, regardless of their channel numbers.

Abstract: An electromagnetic transducer, such as an audio loudspeaker, having an underhung voice coil disposed in a magnetically tapered air gap. The taper provides asymmetry in the magnetic flux field. As the voice coil moves in one direction, the motor becomes stronger and more efficient, and as the voice coil moves in the other direction, the motor becomes weaker and less efficient. This results in an increase in even-order harmonics. The magnetic taper may result from a geometric taper of one or both of the opposing steel pieces which form the gap, or it may result from one or both of them having an at least partially laminated structure. The geometric taper provides a magnetic reluctance gradient along the height of the magnetic air gap. The laminated structure provides a magnetic reluctance gradient through the thickness of the laminated member (e.g. top plate). The magnetic reluctance gradient produces a magnetic flux density gradient along the height of the magnetic air gap.

Abstract: A soundbar of loudspeakers for use with a television or the like. The soundbar includes two, three, or more Bessel Arrays configured to produce sound for a corresponding number of audio channels. To reduce the transducer count and/or the soundbar width, adjacent channels may share a transducer in their respective Bessel Arrays, and/or one or more of the channels may use a Reduced Bessel Array.

Abstract: A dipole loudspeaker in which the oppositely oriented transducers each is a Bessel Array. Optionally, Improved or Super Bessel Arrays are used, and their half-amplitude end position transducers may be shared and aimed in a perpendicular—typically vertical—orientation. The Bessel Dipole is especially useful as a surround channel loudspeaker; for the same effective radiating area and/or sound production, the Bessel Dipole has a narrower cabinet than a conventional two-transducer dipole loudspeaker.

Abstract: An MTM loudspeaker in which the Ms and/or the T is constructed as a Bessel Array. The shapes of the diaphragms, the transducer count, the Bessel type, and/or the acoustic center positioning can be adjusted to achieve desired packing factor, enclosure size, off-axis performance, and so forth.

Abstract: A Bessel Array loudspeaker in which identical transducers are fed full amplitude signals. The half amplitude output at some Bessel positions can be achieved by angling those transducers to the side or up/down. The half amplitude transducers can be coupled to separate cabinets which can be rotated left/right with respect to the full amplitude transducers' cabinet, and the rotation can automatically reconfigure the wiring of the half amplitude transducers. The half amplitude output can alternatively be achieved by driving only half of the voice coil windings of the half amplitude transducers. The other half of their voice coil windings can optionally be driven via a low pass filter, to achieve an Improved Bessel with increased bass output and sensitivity.

Abstract: An e.g. 7-element Bessel Array in which the null or zero positions are occupied with sound producing means producing sound outside the Bessel functional frequency range, such as a higher frequency Bessel Array, a higher frequency MTM, or a port.

Abstract: An optical disc drive including, in a separate sealed chamber, a magnetic disk drive which serves as a cache for the optical disc drive. The optical disc and the magnetic disk are carried on separate spindles which are non-coaxial. Optionally, the optical disc and the magnetic disk overlap.

Abstract: A multi-cylinder four-stroke internal combustion engine enabling a method for on-the-fly switching between two or more firing orders. Switching to the new firing order is done without requiring any tear-down of the engine such as to swap camshafts. Switching can be triggered by the rider, or it can be triggered automatically per conditions such as selected gear, RPM range, track location, velocity, and the like.

Abstract: A loudspeaker in which an electromagnetic transducer drives a chamber-loaded augmented passive radiator (APR). The loudspeaker uses a bandpass enclosure such that the transducer produces sound pressure directly into a listening space, and the APR produces sound pressure into the listening space via an acoustic coupler through a chamber which loads the large diaphragm of the APR. The augmented passive radiator enhances low frequency output, permitting the use of a smaller electromagnetic transducer, which in turn improves high frequency output. This improved loudspeaker system may be used in stand-alone loudspeakers, in-ceiling or in-wall loudspeakers, automotive loudspeakers, pro-audio loudspeakers, and in other applications.

Abstract: A loudspeaker in which a compound driver drives an augmented passive radiator (APR). Either the compound driver and/or the APR may be coupled to the enclosure in a high-pass configuration such that it produces sound pressure directly into a listening space, or in a band-pass configuration such that it produces sound pressure into the listening space via an acoustically coupled loading chamber. The augmented passive radiator enhances low frequency output, permitting the use of a smaller electromagnetic transducer, which in turn improves high frequency output. This improved loudspeaker system may be used in stand-alone loudspeakers, in-ceiling or in-wall loudspeakers, automotive loudspeakers, pro-audio loudspeakers, and in other applications.

Abstract: A disk drive including two or more spindles each carrying one or more media platters. The disk drive may have an industry standard sized chassis. By using reduced diameter platters, two spindles' platters can be fit within the chassis, increasing the capacity and/or performance of the drive. The two spindles' platters may be of the same type, such as magnetic hard disk platters, or they may be different, such as one spindle of hard disk and one spindle of optical disk. Optionally, one spindle's platter may be used as a cache or buffer for the other spindle's platter.

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 improved Bessel array of electromagnetic transducers, in which the Bessel coefficients (phase and/or magnitude) are applied only in the useful high frequency range, where off-axis interference patterns between the outputs of respective transducers cause undesirable acoustic results. One improvement is in using an all-pass filter or the like in lieu of an inverter in the inverting Bessel coefficient path, to provide an in-phase signal in low frequencies and an opposite-phase signal in high frequencies. This achieves the improved off-axis result of a conventional Bessel array, with improved low-frequency maximum sound pressure and efficiency. Another improvement is in using a frequency-dependent voltage divider, such as a shelf circuit, in the half-strength Bessel coefficient paths, to provide full-strength signals in low frequencies and half-strength signals in high frequencies. This achieves even more improved low-frequency maximum sound pressure.

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.