Thx Ltd.

Slot Speaker Technologies, Inc.

Fincham, Lawrence R.

Lawrence R Fincham

Owen Jones

Andrew John Mason

An amplifier circuit that includes a first amplifier that has a first input that receives an input signal, a second input and an output. The amplifier circuit also includes a second amplifier that has a first input that is coupled to the output of said the amplifier and a second input. The circuit further includes a first impedance network Z, a second impedance network Z, a third impedance network Zand a fourth impedance network Z. The first impedance network Zis coupled to a load and the second input of the second amplifier, the second impedance Zis connected the output of the first amplifier and the second input of the first amplifier, the third impedance Zis connected to the output of the first amplifier and the load, the fourth impedance Zis connected the output of the second amplifier and the second input of said first amplifier.

Amplifier circuit with reduced feedforward current

A power supply that includes a first current generator circuit that is coupled to a first transformer and generates a first waveform and a second current generator circuit that is coupled to a second transformer, and generates a second waveform that is out of phase with the first waveform. The first and second waveforms are rectified and combined into a DC output signal. The power supply includes a first coupling circuit that couples the first current generator circuit to the first transformer and a second coupling circuit that couples the second current generator circuit to the second transformer.

Power conversion techniques

A narrow-profile balanced subwoofer or similar speaker includes a number of drivers placed side by side in the same lateral plane, with a first set of drivers facing one direction and second set of drivers facing the opposite direction. Their orientation is such that the sum of the forces from the first set of drivers is equal and opposite the sum of the forces from the second set of drivers, thus cancelling, and the sum of the moments from all of the drivers about a center or pivot point substantially equals zero. The speaker may include three or more drivers, symmetrically or asymmetrically spaced. The drivers may be of the same or different sizes, and the audio signal amplitudes may be adjusted to help balance the speaker. Each set of drivers may output sound into separate sound ducts, which may output sound from one or more apertures.

Slim profile loudspeaker

A narrow profile speaker unit comprises at least one speaker outputting sound towards an internal surface and through a duct with an output terminus, such as a slot, having a narrow dimension, effectively changing the cross-section of the speaker's audio output wave. A pair of speakers may face one another, outputting sound towards a common output slot. Multiple pairs of speakers may be used to form an inline speaker unit for increased sound output. A slotted speaker unit may include multiple speakers facing the same direction, towards a groundplane or reflecting surface, and having parallel apertures for allowing sound radiation. The speaker units may be integral with or attached to electronic appliances such as desktop computers or flatscreen devices, or may be used in automobiles or other contexts.

Narrow profile speaker configurations and systems

A tracking power supply for one or more amplifiers includes one or more cascaded sets of power boost circuits to temporarily boost the positive and/or negative power supply rail, respectively. Each power boost circuit may include a gain element and an energy source such as a capacitor or battery, and the power boost circuits are linked to provide a greater degree of voltage boost when needed. An optional control circuit monitors amplifier output signal levels, or separately amplified input signal levels, and provides power boost control signals to the power boost circuits, which temporarily raise or lower the positive and/or negative supply voltages above or below the nominal voltage rails in tandem with the highest and lowest output signals, respectively, from the amplifier(s).

Tracking power supply with increased boost capability

A sound reproduction system includes one or more arrays of drive units, coupled with sound processing allowing improved steerability, directional control, width control, and/or beam overlay. A speaker column may comprise two arrays facing one another, the drive units being perpendicular to the speaker unit front, with the acoustic output of each line array being compressed, turned and output from an elongate slot. The drive units may be staggered with respect to those in the opposing array. The arrays may be arc-shaped else straight. Selective delays to simulate an arced pattern. Differential delays applied to the drive units in a sub-array allow beam steering. Additional drive units, such as high frequency drivers, may be added along the length of the elongate slot or elsewhere to increase the dynamic frequency range of the speaker system. A collocated sound processor and amplifier output stage may be integrated with the speaker unit.

Audio and power signal distribution for loudspeakers

A power supply includes two or more input waveforms being shaped or selected so that after being separately level-shifted and rectified, their additive combination results in a DC output waveform with substantially no ripple. The power supply may comprise a waveform generator, a level conversion stage for step up or down conversion, a rectification stage, and a combiner. The waveform generator may generate complementary waveforms, preferably identical but phase offset from each other, such that after the complementary waveforms are level-converted, rectified and additively combined their sum will be constant, thus requiring no or minimal smoothing for generation of a DC output waveform. The level conversion may be carried out using transformers or switched capacitor circuits. Feedback from the DC output waveform may be used to adjust the characteristics of the input waveforms.

Power converter with low ripple output

A low dissipation, low distortion amplifier includes a driver amplifier stage and a main output stage, with a plurality of impedance networks providing, among other things, feedback paths from outputs of the driver and main output stages to the input of the driver stage. The impedance networks also provide coupling paths from the outputs of the driver and main output stages to the load. The impedance networks can all be formed of resistors, capacitors, or network combinations thereof. An additional feedback path can be added from the load to the driver stage to flatten out the frequency response at low frequencies. The driver and main output stages may be operated in Class AB and B modes respectively, and/or in Class G or H modes. An intermediate amplifier driver stage may be added between the driver and main output stages.

Low dissipation amplifier

An earphone device comprises an inner casing enclosing one or more miniature drive units, and a movable cap or outer casing that moves relative to the inner casing. The inner casing has an extension member, such as a hollow post, terminating in an acoustic output port. A compressible foam bulb at least partially surrounds the extension member, and is decompressed and compressed by actuation of an adjustable member. The adjustable member may take the form, for example, of a pivoting lever, a helical cam, or a push-rod mechanism, among other things. A flange may be disposed around the periphery of the movable cap, in order to provide a seal surrounding the ear canal region. The compressible material may be gripped by the hollow extension member, and abut the movable cap or flange. Through actuation of the adjustable member, the compressible material may be decompressed and thus elongated for insertion into the wearer's ear, and may be compressed and thus widened or expanded to form an adequate seal with the wearer's ear canal region.

Earphone device

A dynamic power supply for N amplifiers includes first and second power boost circuits which temporarily boost the positive or negative power supply rail, respectively. A control circuit monitors amplifier output signal levels and provides power boost control signals to the power boost circuits, which temporarily raise the positive supply voltage above the nominal voltage level in tandem with the highest output signal from the N amplifiers and lower the negative supply voltage below the nominal voltage level in tandem with the lowest output signal level from the N amplifiers. The power boost circuits each may be coupled to a reservoir capacitor from which current is drawn to provide the power boost. When inactive, the reservoir capacitors charge up from the respective power supply rails. The dynamic power supply is well suited for audio amplification systems.

Efficient power amplifier

A standalone or integrated electronic unit for selectively modifying audio or video data for use with an output device. The electronic unit has one or more audio or video inputs and one or more audio or video outputs for outputting the modified audio or video source material. The unit may include sensors, selectors, and/or logic for selecting from among a plurality of modification profiles and applies the selected profile to the audio or video source material before conveying it to the output device. The modification profile may be used to adapt an audio or video source for a specific type of audio or video playback or output device. For audio, the modification profile may be used to modify audio quality by altering the transfer function, and for video, the modification profile may be used to modify video quality by altering the visual characteristics of the video source signal.

Electronic adapter unit for selectively modifying audio or video data for use with an output device

A narrow profile speaker unit comprises at least one speaker outputting sound towards an internal surface and through a duct with an output terminus, such as a slot, having a narrow dimension, effectively changing the cross-section of the speaker's audio output wave. A pair of speakers may face one another, outputting sound towards a common output slot. Multiple pairs of speakers may be used to form an inline speaker unit for increased sound output. A slotted speaker unit may include multiple speakers facing the same direction, towards a ground plane or reflecting surface, and having parallel apertures for allowing sound radiation. The speaker units may be integral with or attached to electronic appliances such as desktop computers or flatscreen devices, or may be used in automobiles or other contexts.

Growing community of inventors

Santa Rosa, CA, United States of America

Lawrence R Fincham