A method is provided for designing an acoustic correction filter applicable
to a stringed instrument, which is composed of a string member operable to
undergo a vibration, a support member for supporting the string member, a
body member responsive to the vibration transmitted through the support
member for generating a natural sound and a mute attachment for muting the
natural sound. The acoustic correction filter is operable when the natural
sound is muted by the mute attachment for filtering a signal derived from
the vibration so as to create an artificial sound instead of the muted
natural sound. The method is carried out by the steps of acquiring a first
sample signal from the vibration under a mute state, acquiring a second
sample signal from the vibration under a free state, extracting a
difference between the acquired first sample signal and the acquired
second sample signal, and determining a correction characteristic of the
acoustic correction filter based on the extracted difference such that the
acoustic correction filter can filter the signal in accordance with the
determined correction characteristic so as to create the artificial sound
comparable to the natural sound.
