Methods and systems are provided for volume interactions for connected playback devices. In an example implementation, a first playback device applies a state variable update associated with a group of playback devices comprising the first playback device and one or more second playback devices. The state variable update indicates a limited volume range associated with the first playback device. The first playback device renders audio content in synchrony with the one or more second playback devices. Rendering the audio content involves a subwoofer speaker of the first playback device rendering a bass frequency component of the audio content. The first playback device receives input data indicating a group volume adjustment for the group of playback devices and adjusting a playback volume of the first playback device based on the group volume adjustment and the limited volume range.

Methods and systems are provided for volume interactions for connected playback devices. In an example implementation, a first playback device applies a state variable update associated with a group of playback devices comprising the first playback device and one or more second playback devices. The state variable update indicates a limited volume range associated with the first playback device. The first playback device renders audio content in synchrony with the one or more second playback devices. Rendering the audio content involves a subwoofer speaker of the first playback device rendering a bass frequency component of the audio content. The first playback device receives input data indicating a group volume adjustment for the group of playback devices and adjusting a playback volume of the first playback device based on the group volume adjustment and the limited volume range.

A cloud-based equalizer system for a plurality of smart speakers. Each speaker has a wireless range extender connecting to a wireless access point to directly send and receive data, including audio packet transmissions, to and from the cloud. Equalizer settings associated with the audio packet transmissions are retrieved from a cloud-based search and are communicated to and implemented by at least one of the speakers in the plurality of smart speakers. A wireless communication protocol prioritizes audio packet transmissions over other data that may be transmitted to and from each speaker.

A radiofrequency (RF) amplifier includes an input terminal, an output terminal, and a power supply and biasing stage having an output coupled to the input terminal. An amplification stage of the RF amplifier includes a first transistor having a control terminal coupled to the input terminal and a first conduction terminal coupled to the output terminal. The power supply and biasing stage is configured to generate a bias voltage at the control terminal of the first transistor to simultaneously regulate a power supply voltage of the amplification stage to a first voltage and a bias current of the amplification stage to a first current.

Disclosed are drive-by-wire headphones, comprising a USB plug, a headphone cable, a left-ear receiver, a right-ear receiver, and a volume regulator. The USB plug is provided with a power-supply pin, a ground pin, and two signal pins. The headphone cable is provided with a power-supply wire, a ground wire, and two receiver wires corresponding to the pins of the USB plug. The right-ear receiver is connected between the right-ear receiver and the ground wire. The volume regulator is supplied with power by means of the power-supply wire. The volume regulator comprises: a regulation triggering unit used for outputting a volume regulating signal; a processing unit used for determining a voltage regulation value according to the volume regulating signal and outputting the digital voltage regulation value; and a digital-to-analog conversion unit used for converting the digital voltage regulation value to an analog voltage regulation value and applying the analog voltage regulation value to the two receiver wires. Headphones in the present disclosure can regulate the volume and thus would not occupy resources of a processor of an electronic device, thereby improving the response speed of the electronic device to other functions.

Current microphone designs are still using concepts developed in the early 20th century. A transducer followed by a simple buffer with high impedance, low power, and low gain. Even when tubes were replaced by solid state devices the same practice continued, with the low gain triode being replaced by an even smaller power, lower current FET buffer. The invention offers a microphone system intended for professional audio applications that dispenses with these, low power concepts and incorporates elements of a microphone, microphone pre amplifier, and high power mixing console/pre amp line drivers into a single housing. By combining transducer, high fidelity pre amp circuit, and high power line driving stage with a high voltage, high current external power supply, the capabilities of microphones can be greatly increased in many ways. Our approach can be implemented in a variety of circuit topologies including discrete transistors, tubes and integrated circuits, our concept allows microphones to connect directly to analog or digital recording devices without the need for external mixers or pre amplifiers. The design not only allows for unprecedented simplicity in the work flow of the modern recording studio, which combines the use of stand-alone analog records, standalone digital recorder, and computer workstation based recording options, but also eliminates redundant circuits that are present in microphones, microphone pre amps, and mixing consoles, while offering the customer increased value.

Current microphone designs are still using concepts developed in the early 20th century. A transducer followed by a simple buffer with high impedance, low power, and low gain. Even when tubes were replaced by solid state devices the same practice continued, with the low gain triode being replaced by an even smaller power, lower current FET buffer. The invention offers a microphone system intended for professional audio applications that dispenses with these, low power concepts and incorporates elements of a microphone, microphone pre amplifier, and high power mixing console/pre amp line drivers into a single housing. By combining transducer, high fidelity pre amp circuit, and high power line driving stage with a high voltage, high current external power supply, the capabilities of microphones can be greatly increased in many ways. Our approach can be implemented in a variety of circuit topologies including discrete transistors, tubes and integrated circuits, our concept allows microphones to connect directly to analog or digital recording devices without the need for external mixers or pre amplifiers. The design not only allows for unprecedented simplicity in the work flow of the modern recording studio, which combines the use of stand-alone analog records, standalone digital recorder, and computer workstation based recording options, but also eliminates redundant circuits that are present in microphones, microphone pre amps, and mixing consoles, while offering the customer increased value.

Processes and systems for producing glass fibers having regions devoid of glass using submerged combustion melters, including feeding a vitrifiable feed material into a feed inlet of a melting zone of a melter vessel, and heating the vitrifiable material with at least one burner directing combustion products of an oxidant and a first fuel into the melting zone under a level of the molten material in the zone. One or more of the burners is configured to impart heat and turbulence to the molten material, producing a turbulent molten material comprising a plurality of bubbles suspended in the molten material, the bubbles comprising at least some of the combustion products, and optionally other gas species introduced by the burners. The molten material and bubbles are drawn through a bushing fluidly connected to a forehearth to produce a glass fiber comprising a plurality of interior regions substantially devoid of glass.

Disclosed is a power control method for a radio frequency power amplifier, comprising the following steps: S1. reading a power source voltage signal and a power control signal and generating an amplified signal having a linear relationship with the power control signal; S2. according to the amplified signal and saturation information, generating one or more controlled currents, merging each controlled current, and converting the merged total current into voltage; S3. Conducting linear voltage regulation on the converted voltage and generating a base control voltage of the radio frequency power amplifier. The present invention dynamically monitors the saturation information of a pass element to change the base voltage of the radio frequency power amplifier, thus improving additional power efficiency of the radio frequency power amplifier at multiple power level and over a large power source voltage range, and improving the properties of the radio frequency switch thereof.

An electrosurgical generator includes an RF output stage, a current sensor, a voltage sensor, first and second log amplifiers, and a controller. The RF output stage is configured to supply electrosurgical energy to tissue. The current sensor is configured to sense a current of the electrosurgical energy and generate a current signal corresponding to the current of the electrosurgical energy. The first log amplifier is configured to amplify and compress the current signal. The voltage sensor is configured to sense a voltage of the electrosurgical energy and generate a voltage signal in response thereto. The second log amplifier is configured to amplify and compress the voltage signal. The controller is configured to receive the amplified voltage signal and the amplified current signal and operatively control the generation of the electrosurgical energy as a function of the amplified voltage signal and the amplified current signal.