An example playback device includes programming to perform functions including storing an active volume state variable in memory, where the active volume state variable corresponds to a current playback volume. The functions also include storing a volume limit state variable in memory, where the volume limit state variable corresponds to a playback volume limit of the playback device. The functions also include receiving, from a control device, a command to begin playback of media, and determining whether the control device is located in a second zone of the media playback system different from the first zone. Based on whether the control device is located in the second zone of the media playback system different from the first zone, the functions include selecting a startup playback volume to be one of the current playback volume or the playback volume limit, and then playing back media at the startup playback volume.

An example playback device may store an active volume state variable in memory, where the active volume state variable corresponds to a current playback volume. The playback device may also store a volume limit state variable in memory, where the volume limit state variable corresponds to a playback volume limit of the playback device. The playback device may detect a command to begin playback of media from a given source and then select a startup playback volume to be one of the current playback volume and the playback volume limit based on the given source of the command to begin playback. The playback device may then play back media at the startup playback volume.

Radio Frequency (RF) amplifiers with voltage limiting using non-linear feedback are presented herein. According to one aspect, an RF amplifier comprises an amplifier circuit having an input terminal and an output terminal and a non-linear feedback circuit having an input terminal and an output terminal. The input terminal of the non-linear feedback circuit is connected to the output terminal of the amplifier circuit and the output terminal of the non-linear feedback circuit is connected to the amplifier circuit to reduce the gain of the amplifier circuit when an RF voltage swing present at the input terminal of the non-linear feedback circuit exceeds a predefined threshold. In one embodiment, the output terminal of the non-linear feedback circuit is connected to the input terminal of the amplifier circuit. In another embodiment, the output terminal of the non-linear feedback circuit is connected to a bias circuit of the amplifier circuit.

An example playback device may store an active volume state variable in memory, where the active volume state variable corresponds to a current playback volume. The playback device may also store a volume limit state variable in memory, where the volume limit state variable corresponds to a playback volume limit of the playback device. The playback device may detect a command to begin playback of media from a given source and then select a startup playback volume to be one of the current playback volume and the playback volume limit based on the given source of the command to begin playback. The playback device may then play back media at the startup playback volume.

An example playback device may store an active volume state variable in memory, where the active volume state variable corresponds to a current playback volume. The playback device may also store a volume limit state variable in memory, where the volume limit state variable corresponds to a playback volume limit of the playback device. The playback device may detect a command to begin playback of media from a given source and then select a startup playback volume to be one of the current playback volume and the playback volume limit based on the given source of the command to begin playback. The playback device may then play back media at the startup playback volume.

An example playback device may store an active volume state variable in memory, where the active volume state variable corresponds to a current playback volume. The playback device may also store a volume limit state variable in memory, where the volume limit state variable corresponds to a playback volume limit of the playback device. The playback device may detect a command to begin playback of media from a given source and then select a startup playback volume to be one of the current playback volume and the playback volume limit based on the given source of the command to begin playback. The playback device may then play back media at the startup playback volume.

An example playback device may store an active volume state variable in memory, where the active volume state variable corresponds to a current playback volume. The playback device may also store a volume limit state variable in memory, where the volume limit state variable corresponds to a playback volume limit of the playback device. The playback device may detect a command to begin playback of media from a given source and then select a startup playback volume to be one of the current playback volume and the playback volume limit based on the given source of the command to begin playback. The playback device may then play back media at the startup playback volume.

An example first playback device includes programming to perform functions including: (1) storing an active volume state variable in memory, wherein the active volume state variable corresponds to a current playback volume; (2) storing a volume limit state variable in memory, wherein the volume limit state variable corresponds to a playback volume limit of the first playback device; (3) detecting a command to begin playback of media at a proposed playback volume different from the current playback volume; (4) based on comparing (i) the playback volume limit and (ii) the proposed playback volume, selecting a startup playback volume; (5) playing back media at the startup playback volume; and (6) causing at least a second playback.

An audio interface system is disclosed that receives an audio signal from an audio line and outputs a normalised audio signal. An audio interface device of the audio interface system comprises a signal conditioning module, a gain module to apply a gain to the audio signal and an attenuation module to apply an attenuation to the audio signal to output the normalised audio signal. The audio interface device further comprises an interface configured to communicate the normalised signal to an external device. In response to determining that an amplitude of the audio signal does not meet a minimum amplitude requirement or exceed a maximum amplitude requirement, the signal conditioning module is to adjust the amplitude of the audio signal by applying the gain and/or attenuation to meet the requirement.

An audio device is provided. The audio device comprises a controller and an acoustic transducer. The controller is configured to receive an input audio signal. The controller is further configured to generate, via a loudness detector, a loudness level of a first portion of the input audio signal. The controller is further configured to identify a compression curve of a plurality of compression curves corresponding to a user volume setting. The controller is further configured to adjust, via an audio compressor, a second portion of the input audio signal based on the loudness level and the compression curve to generate an output audio signal. The loudness level is determined according to LUFS model.