An electronic signal processor for processing signals includes a complex first filter, one or more gain stages and a second filter. The first filter is characterized by a frequency response curve that includes multiple corner frequencies, with some corner frequencies being user selectable. The first filter also has at least two user-preset gain levels which may be alternately selected by a switch. Lower frequency signals are processed by the first filter with at least 12 db/octave slope, and preferably with 18 db/octave slope to minimize intermodulation distortion products by subsequent amplification in the gain stages. A second filter provides further filtering and amplitude control. The signal processor is particularly suited for processing audio frequency signals.

An electronic signal processor for processing signals includes a complex first filter, one or more gain stages and a second filter. The first filter is characterized by a frequency response curve that includes multiple corner frequencies, with some corner frequencies being user selectable. The first filter also has at least two user-preset gain levels which may be alternately selected by a switch. Lower frequency signals are processed by the first filter with at least 12 db/octave slope, and preferably with 18 db/octave slope to minimize intermodulation distortion products by subsequent amplification in the gain stages. A second filter provides further filtering and amplitude control. The signal processor is particularly suited for processing audio frequency signals.

The invention relates to a method, comprising receiving a first audio signal during an application execution in an apparatus, determining a volume level of a volume control interface for controlling a volume level of the first audio signal, controlling processing the first audio signal by at least one digital signal processing algorithm determined on the basis of the determined volume level of the volume control interface for controlling the volume level of the first audio signal, and outputting the controlled processed first audio signal at the determined volume level of the volume control interface. The invention further relates to an apparatus and a computer program product that perform the method.

The invention relates to a method, comprising receiving a first audio signal during an application execution in an apparatus, determining a volume level of a volume control interface for controlling a volume level of the first audio signal, controlling processing the first audio signal by at least one digital signal processing algorithm determined on the basis of the determined volume level of the volume control interface for controlling the volume level of the first audio signal, and outputting the controlled processed first audio signal at the determined volume level of the volume control interface. The invention further relates to an apparatus and a computer program product that perform the method.

An example playback device includes a first interface for receiving a first audio signal from a first audio source; a second interface for receiving a second audio signal from a second audio source; and a processor configured to: cause the playback device to playback the second audio signal; determine that the first audio signal is present at the first interface; in response to determining that the first audio signal is present at the first interface, (i) cease playback of the second audio signal being played by the playback device and (ii) cause the playback device to playback the first audio signal; receive an instruction to stop the playback device from playing the first audio signal while the first audio signal is still present at the first interface; and arm the playback device such that a subsequent presence of the first audio signal at the first interface causes the playback device to play the first audio signal.

An example playback device includes a first interface for receiving a first audio signal from a first audio source; a second interface for receiving a second audio signal from a second audio source; and a processor configured to: cause the playback device to playback the second audio signal; determine that the first audio signal is present at the first interface; in response to determining that the first audio signal is present at the first interface, (i) cease playback of the second audio signal being played by the playback device and (ii) cause the playback device to playback the first audio signal; receive an instruction to stop the playback device from playing the first audio signal while the first audio signal is still present at the first interface; and arm the playback device such that a subsequent presence of the first audio signal at the first interface causes the playback device to play the first audio signal.

Provided is a preamplifying circuit, including a first amplifier and a second amplifier sequentially connected in series, wherein an output end of the second amplifier is connected to a circuit output end, and an input end of the first amplifier is connected to a circuit input end. The preamplifying circuit further includes a positive feedback branch including a diode group and a third amplifier, wherein one end of the diode group is connected to the input end of the first amplifier. The positive feedback circuit can positively feed part of signals back to the other end of the diode group, so that voltage drops at two ends of the diode group can be reduced, and harmonic distortion caused by nonlinearity of the diode group is reduced. Thus, the sound quality detected by a microphone sensor is improved.

A computer-implemented method to generate an audio output signal is disclosed. The method may include receiving an audio input signal at an automatic gain control (AGC) unit. The method may further include receiving a volume setting indicator signal at the AGC unit. Further, the method may include setting one or more operational parameters for the AGC unit based on the volume setting indicator signal. In addition, the method may include applying a gain to the audio input signal based on the one or more operational parameters to generate an audio output signal at a desired output level.

An electronic signal processor for processing signals includes a complex first filter, one or more gain stages and a second filter. The first filter is characterized by a frequency response curve that includes multiple corner frequencies, with some corner frequencies being user selectable. The first filter also has at least two user-preset gain levels which may be alternately selected by a switch. Lower frequency signals are processed by the first filter with at least 12 db/octave slope, and preferably with 18 db/octave slope to minimize intermodulation distortion products by subsequent amplification in the gain stages. A second filter provides further filtering and amplitude control. The signal processor is particularly suited for processing audio frequency signals.

An electronic signal processor for processing signals includes a complex first filter, one or more gain stages and a second filter. The first filter is characterized by a frequency response curve that includes multiple corner frequencies, with some corner frequencies being user selectable. The first filter also has at least two user-preset gain levels which may be alternately selected by a switch. Lower frequency signals are processed by the first filter with at least 12 db/octave slope, and preferably with 18 db/octave slope to minimize intermodulation distortion products by subsequent amplification in the gain stages. A second filter provides further filtering and amplitude control. The signal processor is particularly suited for processing audio frequency signals.