In some embodiments, a calibration circuit for an audio amplification system can include a tone generator configured to provide a tone having a frequency to an input path of an audio amplifier, such that an input signal provided to the audio amplifier includes the tone, a a first sampling circuit configured to sample an output signal at an output node of the audio amplifier, and a second sampling circuit configured to sample the input signal at an input node of the audio amplifier. The calibration circuit can further include a gain adjustment circuit configured to generate a correction signal based on the sampled output signal and the sampled input signal to correct for a gain variation of the audio amplifier.

In some embodiments, an audio amplifier can include an input node for receiving a digital signal, and a controller coupled to the input node through a feed-forward path. The controller can be configured to generate a driving signal based on the digital signal. The audio amplifier can further include a driver configured to provide an amplified signal at an output node based on the driving signal, and a feedback circuit that couples the output node of the driver to the controller. The feedback circuit can be configured to provide a feedback signal for comparison with a reference signal representative of the digital signal to generate an error signal, such that the feedback circuit provides a form of the error signal to the controller for adjustment of the digital signal.

A control device includes: a difference calculator that calculates a maximum gain difference between frequency characteristics of an audio signal and desired frequency characteristics in a predetermined frequency band; a center frequency calculator that calculates a center frequency between a first frequency at which the gain difference is 1/√2 times the maximum gain difference and which is closest to a peak frequency corresponding to the maximum gain difference among one or more frequencies lower than the peak frequency and a second frequency at which the gain difference is 1/√2 times the maximum gain difference and which is closest to the peak frequency among one or more frequencies higher than the peak frequency; a determiner that determines parameters of an equalizer based on the maximum gain difference and the center frequency; and an outputter that outputs the parameters to the equalizer.

In some embodiments, a method for performing at least one of enhancement, decoding, or rendering of a multichannel audio signal in response to compression feedback or feedback from a smart amplifier. For example, the compression feedback may be indicative of amount of compression applied to each of multiple frequency bands, of the audio signal or an enhanced audio signal generated in response thereto. The enhancement (e.g., bass enhancement) may include dynamic routing of audio content of the input audio signal between channels of an enhanced audio signal generated in response thereto. The enhancement and compression may be performed on a per speaker class basis. Other aspects are systems (e.g., programmed processors) and devices (e.g., devices having physically-limited bass reproduction capabilities, such as, for example, a notebook or laptop computer, tablet, soundbar, mobile phone, or other device with small speakers) configured to perform any embodiment of the method.

To avoid damage from overheating, playback device operation can be modulated based on input from temperature sensors. An example method includes obtaining, via one or more temperature sensors carried by the playback device, temperature data. Based on the temperature data, a first temperature parameter is detected. In response to detecting the first temperature parameter, a gain of audio playback is decreased by a first amount. After decreasing the gain of audio playback by the first amount, a second temperature parameter is detected. In response to detecting the second temperature parameter, the gain of audio playback is decreased by a second amount different than the first amount.

A data processing apparatus includes one or more processors, and one or more memories including instructions stored thereon that, when executed by the one or more processors, cause the data processing apparatus to function as a copy unit configured to generate second sound data by copying first sound data, and a processing unit configured to apply a first gain to at least one of the first sound data and the second sound data.

Systems and methods for automatically adjusting device volume based on learned volume preferences are disclosed herein. A first device receives a wireless signal from a second device. A signal strength of the wireless signal is determined, and a location of the second device is determined based on the signal strength of the wireless signal. Historical volume level data for the first device is retrieved from memory. A target volume level for the first device is determined based on the location of the second device and the historical volume level data. A volume setting of the first device is automatically adjusted to the target volume level.

Systems and methods are provided herein for responding to a voice command at a volume level based on a volume level of the voice command. For example, a media guidance application may detect, through a first voice-operated user device of a plurality of voice-operated user devices, a voice command spoken by a user. The media guidance application may determine a first volume level of the voice command. Based on the volume level of the voice command, the media guidance application may determine that a second voice-operated user device of the plurality of voice-operated user devices is closer to the user than any of the other voice-operated user devices. The media guidance application may generate an audible response, through the second voice-operated user device, at a second volume level that is set based on the first volume level of the voice command.

A virtual meeting system is discussed herein. An online meeting application can provide a parallel virtual meeting between or among two or more participants of a main virtual meeting. The parallel virtual meeting permits two or more participants of the main virtual meeting to have a “smaller-sized” meeting in parallel with the main virtual speaker or presentation while still participating in the main virtual meeting. Therefore, the participants of the parallel virtual meeting do not have to connect via another device or application and can avoid disrupting the main virtual meeting. The parallel virtual meeting can permit two separate meetings, such as one meeting with all participants and one meeting with a subset of all the participants.

Illustrative embodiments of systems and methods for enhanced vibration and electrical noise performance in magnetostrictive transmitters are disclosed. In one embodiment, a signal conditioning circuit may comprise an instrumentation amplifier configured to receive and amplify an analog measurement signal, an active high pass filter configured to reduce noise in a signal output by the instrumentation amplifier, a variable gain amplifier stage configured to further amplify a signal output by the active high pass filter, a distance detection module configured to process a signal output by the variable gain amplifier stage to determine a distance measurement associated with the analog measurement signal received by the instrumentation amplifier, and a programmable control circuit configured to control a gain level of the variable gain amplifier stage and to receive data concerning the signal output by the variable gain amplifier stage, including the distance measurement, from the distance detection module.