Acoustic processing device and acoustic processing method

An acoustic processing device, comprising:

• an input reception unit configured to receive an input of a value of a parameter defining a phase difference to be provided between a pair of audio signals;
• a filter coefficient calculation unit configured to calculate a filter coefficient group corresponding to each of the pair of audio signals based on the input value received by the input reception unit;
• and
• a filter processing unit configured to provide a phase difference defined by the input value between the pair of audio signals by performing filter processing on each of the pair of audio signals based on the filter coefficient group calculated by the filter coefficient calculation unit;
• wherein the parameter includes a center frequency of the phase difference provided between the pair of audio signals, a quality factor, and a phase difference at the center frequency;
• wherein the filter coefficient calculation unit is configured to:
• calculate a frequency of a first control target with respect to one of the pair of audio signals based on the input value and calculate a frequency of a second control target with respect to the other of the pair of audio signals based on the input value;
• calculate a bandwidth of a filter based on the frequency of the first control target and the frequency of the second control target;
• calculate a first filter coefficient group corresponding to the one audio signal based on the frequency and the bandwidth of the first control target;
• and
• calculate a second filter coefficient group corresponding to the other audio signal based on the frequency and the bandwidth of the second control target and the bandwidth.

An acoustic processing method for execution in a computer, the method comprising the steps of:

• receiving an input of a value of a parameter defining a phase difference to be provided between a pair of audio signals, the pair of audio signals being left and right channel audio signals respectively corresponding to a pair of left and right speakers;
• calculating a filter coefficient group corresponding to each of the pair of audio signals based on the received input value;
• and
• providing the phase difference by an all-pass filter, the phase difference being defined by the input value between the pair of audio signals by performing filter processing on each of the pair of audio signals based on the calculated filter coefficient group;
• wherein the parameter includes a center frequency of the phase difference provided between the pair of audio signals, a quality factor, and a phase difference at the center frequency.