An audio system has an amplifier for driving an audio actuator and includes a switched-mode power supply that draws power from a power source (e.g., battery) to supply power to the amplifier, a capacitor charged by the switched-mode power supply to supply power to the amplifier, and a feed-forward compressor that performs dynamic range compression of an audio input to provide an audio output for amplification by the amplifier. The compressor includes a sidechain frequency-biasing filter that generates a frequency-biased version of the audio input that is attenuated as frequency increases which causes the compressor to decrease the compression as frequency increases. A control block limits current drawn from the battery by the switched-mode power supply independent of audio input frequency, but the frequency-biasing filter enables the amplifier to service audio power transients greater than the current-limited power supply can supply by advantageously concurrently sourcing extra power from the capacitor.

An audio processing device includes a signal processing circuit, a power switch circuit, a power amplifier and a detection circuit. The signal processing circuit is configured to process an audio input to generate an audio signal. The power switch circuit is configured to generate an operating voltage. The power amplifier is coupled with the signal processing circuit and the power switch circuit, and configured to drive a load circuit by the operating voltage according to the audio signal. The detection circuit is coupled with the signal processing circuit and the power switch circuit, configured to obtain a volume value from the audio signal and compare the volume value with a first volume threshold to generate a comparison result, and configured to control, according to the comparison result, the power switch circuit to set the operating voltage to have a corresponding one of multiple voltage levels.

A method of operating a headphone configured to be removed from and placed in close proximity to a user's ear can include generating an input signal by an input signal generating device. The method can also include determining whether an insertion event has occurred based on the generated input signal and causing the headphone to operate in 5 a low power mode responsive to an absence of an insertion event determination after a first period of time. The method can also include causing the headphone to operate in an ultra-low power mode responsive to the absence of an insertion event determination after a second period of time that occurs after the first period of time, the ultra-low power mode having a lower power consumption than the low power mode.

A computing device capable of controlling a networked media playback system receives data identifying a first zone player, a second zone player, and a zone scene including a predefined grouping of zone players including at least the first zone player and the second zone player. The computing device displays a representation of available zone players in the networked media playback system including a first selectable indication of the first zone player, a second selectable indication of the second zone player, and a third selectable indication of the zone scene that, when selected, causes the zone scene to be invoked such that the predefined grouping of zone players becomes configured for synchronous playback of media. While displaying the representation, the computing device receives a user input indicating that the zone scene has been selected to be invoked. Based on the user input, the computing device causes the zone scene to be invoked.

A computing device capable of controlling a networked media playback system receives data identifying a first zone player, a second zone player, and a zone scene including a predefined grouping of zone players including at least the first zone player and the second zone player. The computing device displays a representation of available zone players in the networked media playback system including a first selectable indication of the first zone player, a second selectable indication of the second zone player, and a third selectable indication of the zone scene that, when selected, causes the zone scene to be invoked such that the predefined grouping of zone players becomes configured for synchronous playback of media. While displaying the representation, the computing device receives a user input indicating that the zone scene has been selected to be invoked. Based on the user input, the computing device causes the zone scene to be invoked.

An apparatus for processing an audio signal includes an audio signal analyzer and a filter. The audio signal analyzer is configured to analyze an audio signal to determine a plurality of noise suppression filter values for a plurality of bands of the audio signal, wherein the analyzer is configured to determine a noise suppression filter value so that a noise suppression filter value is greater than or equal to a minimum noise suppression filter value and so that the minimum noise suppression value depends on a characteristic of the audio signal. The filter is configured for filtering the audio signal, wherein the filter is adjusted based on the noise suppression filter values.

In an audio encoder, for audio content received in a source audio format, default gains are generated based on a default dynamic range compression (DRC) curve, and non-default gains are generated for a non-default gain profile. Based on the default gains and non-default gains, differential gains are generated. An audio signal comprising the audio content, the default DRC curve, and differential gains is generated. In an audio decoder, the default DRC curve and the differential gains are identified from the audio signal. Default gains are re-generated based on the default DRC curve. Based on the combination of the re-generated default gains and the differential gains, operations are performed on the audio content extracted from the audio signal.

A sound output device includes: first circuitry, connected to a first audio device, that outputs sound based on sound output data via the first audio device according to first sound volume data; and second circuitry connected to a second audio device, including an amplifier that amplifies sound to be output from the second audio device according to second sound volume data. The second circuitry controls a value of the second sound volume data to be a fixed value, receives, from the first circuitry, the sound output data and the first sound volume data, and outputs sound based on the sound output data that is received, via the second audio device, according to the first sound volume data that is received.

A method for processing an audio signal includes setting target loudness; receiving metadata of an audio signal from a server; and adjusting the loudness of the audio signal by using the received metadata, so that the loudness of the audio signal corresponds to the set target loudness.

The invention relates to a method for adapting the applied volume gain in an amplifier controlling at least one loudspeaker of an enclosure according to the desired volume gain selected by a user on a scale increased by a maximum desired volume gain, including the following steps: determining (204) the effective intensity applied to at least one loudspeaker, calculating (206, 208) a maximum volume gain from: the desired volume gain, the effective intensity applied to the loudspeaker, thermal characteristics of the loudspeaker, the maximum desired volume gain, calculating (210) an increasing monotonic function providing an variable applied volume gain according to the desired volume gain such that the image of the maximum desired volume gain by the monotonic function is equal to the maximum volume gain, applying (212), to the amplifier, as applied volume gain, the minimum of the maximum volume gain and the variable applied volume gain for the desired volume gain.