An audio signal processing circuit includes a filter, a gain control circuit, and a bass boost circuit. The filter filters an audio signal and produces a filtered signal accordingly. The gain control circuit divides the filtered signal in the time domain into a first segment and a second segment that are substantially equal in length, measures a first amplitude of the first segment and a second amplitude of the second segment, and generates a gain based on the first amplitude which is greater than the second amplitude. The bass boost circuit adjusts the amplitudes of the first segment and the second segment according to the gain.

A system that performs automatic gain control (AGC) using different decay rates. The system may select a slow decay rate to track a loudness level within speech (e.g., within an utterance), improving audio quality and maintaining dynamic range for an individual voice, while selecting a fast decay rate to track the loudness level after a gap of silence (e.g., no voice activity detected for a duration of time) or during large level changes (e.g., actual speech loudness is lower than estimated speech loudness for a duration of time). This improves an accuracy of the loudness estimate and therefore a responsiveness of the automatic gain control, resulting in an improved user experience.

Methods and systems are provided for independent audio volume control. An audio system may include a circuit for controlling one or both of generation and output of combined audio, with the circuit being configured to determine, based on user input, a mix setting applicable in the audio system to mixing of a first audio and a second audio when generating the combined audio, wherein the combined audio comprises at least a portion of each of the first audio and the second audio; determine a corresponding volume setting applicable at an audio output element of the audio system during outputting of the combined audio; determine a corresponding delay applicable to one or both of the mix setting and the volume setting; and apply one or both of the mix setting and the volume setting based on at least the delay.

In some embodiments, a method for processing an audio signal in an audio processing apparatus is disclosed. The method includes receiving an audio signal and a parameter, the parameter indicating a location of an auditory event boundary. An audio portion between consecutive auditory event boundaries constitutes an auditory event. The method further includes applying a modification to the audio signal based in part on an occurrence of the auditory event. The parameter may be generated by monitoring a characteristic of the audio signal and identifying a change in the characteristic.

Example techniques may provide volume enhancements to a media playback system. An example implementation involves a first playback device in a first playback configuration playing audio at a first volume level and storing the first volume level in association with the first playback configuration. The first playback device receives instructions to change to a second playback configuration. Based on receiving the instructions, the first playback device joins a synchrony group with a second zone and adjusts the first playback device to play audio at a second volume level which is based on a volume level of a second playback device in the second zone. While in the second playback configuration, the first playback device receives instructions to change to the first playback configuration and, based on the instructions, leaves the synchrony group and adjusts the first playback device to play audio content at the stored first volume level.

An amplification system which includes a source of electrical audio signals, a first amplifier, a second amplifier, a plurality of loudspeakers, and a first phase of the first amplifier and a second phase of the second amplifier reproduced in parallel having a time delay between first and second phase amplification for out of phase correction. The time delay is configured to correct poor sound signals while amplifying weaker harmonics and sound signals of different frequencies, thereby adjusting sound output of the amplification system and acoustical characteristics of a room. The amplification system is useful for providing improved sound quality and increased audio efficiencies.

A sound pickup method includes splitting a sound pickup signal of a microphone of which sound pickup in a predetermined range is blocked by an acoustic obstacle, into a plurality of sound pickup signals and subjecting at least one sound pickup signal among the plurality of sound pickup signals to band limitation processing, and comparing characteristic amounts of the plurality of sound pickup signals including the sound pickup signal after being subjected to the band limitation processing and controlling a gain of the microphone in accordance with a result of comparing the characteristic amounts.

In one aspect, an example method includes (i) determining, by a playback device, a first loudness level of a first portion of first media content from a first source while the playback device presents the first media content, with the first portion having a first length; (ii) switching, by the playback device, from presenting the first media content from the first source to presenting second media content from a second source; (iii) based on the switching, determining, by the playback device, second loudness levels of second portions of the first media content while the playback device presents the second media content, with the second portions having a second length that is shorter than the first length; and (iv) while the playback device presents the second media content, adjusting, by the playback device, a volume of the playback device based on one or more of the second loudness levels.

Methods and apparatus to perform an automated gain control protocol with an amplifier based on historical data corresponding to contextual data are disclosed. An example apparatus includes a controller to select an automatic gain control (AGC) parameter for an AGC protocol based on historical data corresponding to contextual data, the contextual data including at least one of a time during which the AGC protocol is performed, a panelist identified by a meter, demographics of an audience identified by the meter, a location of the meter, a station identified by the meter, a media type identified by the meter, or a sound pressure level identified by the meter; and a processor to perform the AGC protocol based on the selected AGC parameter.

The present application discloses playback devices and networks, software for operating playback devices and playback device networks, and methods of operating playback devices and networks, where an individual network device is configured to switch between operating various operating modes comprising a non-paired mode and a paired mode, where the playback device is configured to output various channels of audio content within various audio frequency ranges while operating in the various operating modes.