Abstract: Embodiments provide methods, apparatuses, and systems for performing crosstalk cancellation and/or generation of virtual speakers. An audio processor may include a crosstalk cancellation circuit and a linearization circuit. The linearization circuit may offset the frequency response of the crosstalk cancellation circuit to provide an overall frequency response that is flat. A virtual speaker circuit may receive an input signal associated with an output channel and pass the input signal to the output channel unmodified. The virtual speaker circuit generates a virtualization signal based on the input signal and passes the virtualization signal to another physical channel. The virtualization signal may be generated further based on an ipsilateral head-related transfer function (HRTF) and a contralateral HRTF that correspond to a virtual speaker location of a virtual speaker generated by the virtual speaker circuit. Other embodiments may be described and/or claimed.

Abstract: Embodiments provide an audio amplifier circuit with integrated (built-in) filter (e.g., a digital-to-analog converter (DAC) filter). The audio amplifier circuit may have a non-flat (e.g., low-pass) closed loop frequency response. The audio amplifier circuit may include a low pass filter coupled between an input terminal that receives the input analog audio signal and the input of the gain stage of the amplifier. In some embodiments, additional impedance networks may be included to produce a desired low-pass filter response, such as a second order filter, a third order filter, and/or another suitable filter response. Other embodiments may be described and/or claimed.

Abstract: Embodiments provide a power management system for a battery-powered audio device. The system includes bi-directional power conversion and control circuitry to implement a corresponding control scheme. The system may be switchable between a charge mode, during which the power conversion and control circuitry charges the battery of the audio device and the AC/DC adapter provides an amplifier supply voltage to one or more amplifiers of the audio device, and a discharge mode, in which the power conversion and control circuitry may provide a regulated amplifier supply voltage to the one or more amplifiers that is regulated based on one or more operating conditions of the system. The system may provide reduced cost and reduced power consumption and reduced size compared with prior systems.

Abstract: Embodiments provide an audio amplifier circuit with integrated (built-in) filter (e.g., a digital-to-analog converter (DAC) filter). The audio amplifier circuit may have a non-flat (e.g., low-pass) closed loop frequency response. The audio amplifier circuit may include a low pass filter coupled between an input terminal that receives the input analog audio signal and the input of the gain stage of the amplifier. In some embodiments, additional impedance networks may be included to produce a desired low-pass filter response, such as a second order filter, a third order filter, and/or another suitable filter response. Other embodiments may be described and/or claimed.

Abstract: 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 Z1, a second impedance network Z2, a third impedance network Z3 and a fourth impedance network Z4. The first impedance network Z1 is coupled to a load and the second input of the second amplifier, the second impedance Z2 is connected the output of the first amplifier and the second input of the first amplifier, the third impedance Z3 is connected to the output of the first amplifier and the load, the fourth impedance Z4 is connected the output of the second amplifier and the second input of said first amplifier.

Abstract: 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.

Abstract: Embodiments provide a power management system for a battery-powered audio device. The system includes bi-directional power conversion and control circuitry to implement a corresponding control scheme. The system may be switchable between a charge mode, during which the power conversion and control circuitry charges the battery of the audio device and the AC/DC adapter provides an amplifier supply voltage to one or more amplifiers of the audio device, and a discharge mode, in which the power conversion and control circuitry may provide a regulated amplifier supply voltage to the one or more amplifiers that is regulated based on one or more operating conditions of the system. The system may provide reduced cost and reduced power consumption and reduced size compared with prior systems.

Abstract: 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.

Abstract: 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.

Abstract: 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).

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A vehicle sound system encompasses a combination of speaker configuration, speaker placement, and sound processing to improve sound quality. A pair of speakers (or rows of speakers) are placed close together and located in the front of the console or dashboard with their geometric center on or near the vehicle's central axis. A sound processor acts to “spread” the sound image produced by the two closely spaced speakers by employing a cross-cancellation technique in which the cancellation signal is derived from the difference between the left and right channels. The resulting difference signal is scaled, delayed (if necessary), and spectrally modified before being added in opposite polarities to the left and right channels. The pair of speakers may be placed on a common baffle or mounting surface or in a common housing enclosure, with sound being carried through one or more ducts and emanating out of a slot.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A sound reproduction system comprises a left and right speakers located in close proximity, and a sound processor which provides audio signals to the pair of speakers. The sound processor preferably derives a cancellation signal from the difference between the left and right channels. The resulting difference signal is scaled, delayed (if necessary), and spectrally modified before being added to the left channel and, in opposite polarity, to the right channel. The spectral modification to the difference channel preferably takes the form of a low-frequency boost over a specified frequency range, in order to restore the correct timbral balance after the differencing process. Additional phase-compensating all-pass networks may be inserted in the difference channel to correct for any extra phase shift contributed by the spectral modifying circuit. The technique may be used in a surround sound system.