Patent ID: 8737642

Claim:
An audio signal processing apparatus comprising: a harmonic overtone adder and an equalizer; the harmonic overtone adder including a high-pass filter, a first filter, an harmonic overtone generator, and a first combining unit; and the equalizer including a second filter, a level detector, a gain controller, and a second combining unit, wherein the high-pass filter is for extracting from an input signal a first frequency component equal to or higher than a first predetermined frequency (f 0 ), and for supplying the first frequency component to the first combining unit, the first filter is for extracting from the input signal a second frequency component equal to or lower than f 0 , and for supplying the second frequency component to the harmonic overtone generator, the harmonic overtone generator is for generating a frequency-doubled harmonic overtone component from the second frequency component, and for supplying the frequency-doubled harmonic overtone component to the first combining unit, the first combining unit is for combining at least the first frequency component and the frequency-doubled harmonic overtone component to produce a first signal, and for supplying the first signal to the equalizer, the second filter is for extracting from the first signal a third frequency component, and for supplying the third frequency component to the gain controller, the level detector is for detecting a level of one of the first signal and the third frequency component, and for supplying a detection signal to the gain controller, the gain controller is for generating a fourth frequency component from the third frequency component, the fourth frequency component and the third frequency component having similar frequency characteristics, dynamically controlling a level of the fourth frequency component based on the detection signal, and supplying the fourth frequency component to the second combining unit, and the second combining unit is for combining the first signal with the fourth frequency component, and for supplying an output signal.