The present invention provides methods and systems for digital processing of an input audio signal. Specifically, the present invention includes a high pass filter configured to filter the input audio signal to create a high pass signal. A first filter module then filters the high pass signal to create a first filtered signal. A first compressor modulates the first filtered signal to create a modulated signal. A second filter module then filters the modulated signal to create a second filtered signal. The second filtered signal is processed by a first processing module. A band splitter splits the processed signal into low band, mid band, and high band signals. The low band and high band signals are modulated by respective compressors. A second processing module further processes the modulated low band, mid band, and modulated high band signals to create an output signal.

Apparatus and methods for generating an encoded audio bitstream, including by including program loudness metadata and audio data in the bitstream, and optionally also program boundary metadata in at least one segment (e.g., frame) of the bitstream. Other aspects are apparatus and methods for decoding such a bitstream, e.g., including by performing adaptive loudness processing of the audio data of an audio program indicated by the bitstream, or authentication and/or validation of metadata and/or audio data of such an audio program. Another aspect is an audio processing unit (e.g., an encoder, decoder, or post-processor) configured (e.g., programmed) to perform any embodiment of the method or which includes a buffer memory which stores at least one frame of an audio bitstream generated in accordance with any embodiment of the method.

Systems and methods to provide distortion sensing, prevention, and/or distortion-aware bass enhancement in audio systems can be implemented in a variety of applications. Sensing circuitry can generate statistics based on an input signal received for which an acoustic output is generated. In various embodiments, the statistics can be used such that a multi-notch filter can be used to provide input to a speaker to generate the acoustic output. In various embodiments, the statistics from the sensing circuitry can be provided to a bass parameter controller coupled to bass enhancement circuitry to operatively provide parameters to the bass enhancement circuitry. The bass enhancement circuitry can provide a bass enhanced signal for generation of the acoustic output, based on the parameters. Various combinations of a multi-notch filter and bass enhancement circuitry using statistics from sensing circuitry can be implemented to provide an enhanced acoustic output. Additional apparatus, systems, and methods are disclosed.

An electronic device according to various embodiments may include a processor, wherein the processor may be configured to designate a maximum amplitude of an audio signal as a designated range, wherein designating the maximum amplitude of the audio signal as the designated range comprises processing the audio signal with the designated range according to a designated gain, to determine, based at least on hearing recognition characteristics of a human per frequency band of the processed audio signal, whether to tolerate distortion in the processed audio signal, to reduce, based at least on determining not to tolerate the distortion in the processed audio signal, a gain of the processed audio signal, and to adjust, based at least on determining to tolerate the distortion in the processed audio signal, the gain of the processed audio signal based on the hearing recognition characteristics.

A dry audio signal may be received. An envelope of the dry audio signal may be compared to a threshold of the playback device to determine a dry excess. A filter may be applied to the dry audio signal to generate a wet audio signal. An envelope of the wet audio signal may be compared to the threshold to determine a wet excess. Based on the dry and wet excess, a dry gain may be determined for the dry audio signal and a wet gain may be determined for the wet audio signal. The wet audio signal and the dry audio signals may be mixed in proportion to respective gains. The mixed audio signal may avoid exceeding an operational limit associated with audio playback on the playback device.

A system capable of self-adjusting both sound level and spectral content to improve audibility and intelligibility of electronic device audible cues. Audible cues are stored as sound files. Ambient noise is detected, and the output of the audible cues is altered based on the ambient noise. Various embodiments include processed sound files that are more robust in noisy environments.

A system capable of self-adjusting both sound level and spectral content to improve audibility and intelligibility of electronic device audible cues. Audible cues are stored as sound files. Ambient noise is detected, and the output of the audible cues is altered based on the ambient noise. Various embodiments include processed sound files that are more robust in noisy environments.

A signal channel expanding system based on PAD is provided, including a motherboard disposed on an array tester and a plurality of array test pads disposed on a periphery of the motherboard and configured to control the motherboard; each of the array test pads includes a plurality of pins, each of the pins corresponds to a signal channel, the array test pads include at least two left driving array test pads and at least two right driving array test pads. Compared with the related art, in the signal channel expanding system based on PAD in the disclosure, by using at least two left driving array test pads and at least two right driving array test pads on the periphery of the motherboard, the number of the pins on the periphery of the motherboard can be multiplied and the pin size can remain unchanged without lengthening the test jig.

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.

An audio equalizer circuit for controlling and modifying an audio signal includes a signal divider positioned to receive an audio signal from an audio source. The divided audio signal is then passed through multiple bandpass filters situated in parallel with one another. One or more of the bandpass filters includes a compressor in order to limit the dynamic range of the audio source. After the compressor, the audio circuit may include two summation circuits with the second compressor interposed between the two.