Abstract: There is disclosed a method of a dual filter duet-sound generating method, by allowing an electronic musical instrument with duet-note capability to simultaneously output a harmonious chord in an instrument voice different from that of the depressed melody keyboard note, each duet note being respectively output in different instrument's voice. The electronic musical instrument for carrying out the invention includes: a microputer 11 for control, a sound-generator IC 21 for generating a duet-sound, a plurality of instrument voice filters, a plurality of buffers connected between the sound-generator and the instrument voice filters, a plurality of inventers for control, a plurality of switches at the user interface, a musical keyboard, amplifiers, and a speaker to produce musical sounds.