Patent ID: 8178772

Claim:
A resonance sound adding apparatus for a keyboard instrument, comprising: a resonator group comprising resonators and a first adder, the resonators generating resonance sound data of given resonant frequencies based on sound signal data corresponding to a pitch of a key which is struck, each of the resonators including a delay circuit configured to delay an input based on delay time data indicating a delay time, a second adder configured to add an output from the delay circuit to input sound signal data, and a first low-pass filter configured to receive an output from the second adder and to perform low-pass filtering by a cutoff frequency depending on a filter control signal on the output from the second adder, and an output from the first low-pass filter inputting to the delay circuit, and the first adder adding outputs from the resonators; a third adder configured to add the sound signal data and an output from the resonator group; a storage device configured to store a coefficient table containing delay time data to be provided to each of the resonators; and a delay controller configured to read different items of the delay time data from the coefficient table and supply the different items of the delay time data to the resonators; wherein each of the items of the delay time data corresponds to an intermediate value between pitches of two adjacent keys of the keyboard, and does not match with frequencies corresponding to pitches of keys of the keyboard instrument.