Audio signal processing method and apparatus device

An audio signal processing method comprising the steps of:

• supplying an audio signal to each of a plurality of digital filters;
• respectively supplying outputs from the plurality of digital filters to a plurality of speakers arranged in a speaker array to form a sound field;
• setting a predetermined delay time in each of the plurality of digital filters so that transmission delay times with which the audio signal arrives at a first point in the sound field via each of the plurality of digital filters and each of the plurality of speakers will coincide with each other;
• and
• adjusting an amplitude characteristic of the plurality of digital filters so that a low-pass filter characteristic will be given to a synthesis response of the audio signal at a second point in the sound field.