Abstract: A method and a control circuit for performing synchronization on playback of multiple electronic devices are provided, where the multiple electronic devices include a master device and a slave device. The method includes: utilizing the master device to receive audio data from a far-end device to be master audio data, and transmitting the master audio data to the slave device to be slave audio data, where the slave device generates ultrasound data according to the slave audio data, to make the slave device play the slave audio data and the ultrasound data; utilizing a calibration circuit to estimate a delay value between the ultrasound data received by a microphone of the master device and the master audio data; and utilizing a delay circuit to control a delay of the master audio data according to the delay value, to generate master output audio data for being played by the master device.

Abstract: 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.

Abstract: An audio playback method includes the following steps: receiving an ultrasound signal via a microphone; processing the ultrasound signal to obtain a characteristic value of the ultrasound signal; obtaining time lag information based on the characteristic value; and controlling audio delay according to the time lag information.

Abstract: 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.

Abstract: An audio playback method includes the following steps: receiving an ultrasound signal via a microphone; processing the ultrasound signal to obtain a characteristic value of the ultrasound signal; obtaining time lag information based on the characteristic value; and controlling audio delay according to the time lag information.

Abstract: A method for calculating excursion of a diaphragm of a speaker, which includes: calculating a DC resistance based on a feedback signal of the speaker; calculating an impedance based on the feedback signal and the DC resistance; calculating a transfer function between a signal and a velocity of the diaphragm of the speaker based on the DC resistance, the impedance, and a force factor; and calculating the excursion of the diaphragm of the speaker based on an input signal and the transfer function.

Abstract: An audio enhancement device including an audio-calculating module, a ratio-calculating module, a minimum-tracking module, a weighting-calculating module and a mixing module is provided. The audio-calculating module calculates a mid signal and a side signal according to a sum and a difference of an input first channel signal and an input second channel signal. The ratio-calculating module calculates a side-mid ratio of the side signal relative to the mid signal. The minimum-tracking module tracks a side-mid ratio minimum. The weighting-generating module determines a first and a second weighting values according to the side-mid ratio minimum. The mixing module weights the mid signal and the side signal based on the first and the second weighting values respectively and adjusts the input first channel signal and the input second channel signal accordingly to generate an enhanced first channel signal and an enhanced second channel signal.

Abstract: An audio enhancement device including an audio-calculating module, a ratio-calculating module, a minimum-tracking module, a weighting-calculating module and a mixing module is provided. The audio-calculating module calculates a mid signal and a side signal according to a sum and a difference of an input first channel signal and an input second channel signal. The ratio-calculating module calculates a side-mid ratio of the side signal relative to the mid signal. The minimum-tracking module tracks a side-mid ratio minimum. The weighting-generating module determines a first and a second weighting values according to the side-mid ratio minimum. The mixing module weights the mid signal and the side signal based on the first and the second weighting values respectively and adjusts the input first channel signal and the input second channel signal accordingly to generate an enhanced first channel signal and an enhanced second channel signal.

Abstract: A method for calculating excursion of a diaphragm of a loudspeaker is provided. The loudspeaker includes a diaphragm and is driven by a voltage signal. The method includes: a) low-pass filtering the voltage signal and a current signal inputted to the loudspeaker to generate a low-pass filtered voltage signal and a low-pass filtered current signal, respectively; b) calculating a direct-current (DC) resistance of the loudspeaker according to the low-pass filtered voltage signal and the low-pass filtered current signal; c) calculating a vibration velocity of the diaphragm according to the voltage signal, the current signal and the DC resistance; and d) calculating the excursion of the diaphragm according to the vibration velocity. Step (a) to step (d) involve real-number calculations.

Abstract: An apparatus for processing an audio input signal is provided and includes an audio processing circuit and an audio compressing circuit. The audio processing circuit receives the audio input signal, and enhances a first frequency part of the audio input signal to output a bass-enhancement signal. The audio compressing circuit is coupled to the audio processing circuit, and reduces a gain of a second frequency part of the bass-enhancement signal to output an audio output signal.

Abstract: A harmonic generating apparatus and the method are provided, which are used to enhance the quality of the bass audio signals. The method includes the steps of: providing a frequency signal having a present level and a preceding level; comparing the present level with the preceding level to generate a compared result; and generating the plurality of harmonics based on the compared result.

Abstract: A harmonic generating apparatus and the method are provided, which are used to enhance the quality of the bass audio signals. The method includes the steps of: providing a frequency signal having a present level and a preceding level; comparing the present level with the preceding level to generate a compared result; and generating the plurality of harmonics based on the compared result.

Abstract: An apparatus for processing an audio input signal is provided and includes an audio processing circuit and an audio compressing circuit. The audio processing circuit receives the audio input signal, and enhances a first frequency part of the audio input signal to output a bass-enhancement signal. The audio compressing circuit is coupled to the audio processing circuit, and reduces a gain of a second frequency part of the bass-enhancement signal to output an audio output signal.