Patent ID: 8901408

Claim:
An electronic keyboard musical instrument comprising: a keyboard having a plurality of keys, and outputting tone information corresponding to depression of the keys; a casing having a planar region defined by a surrounding wall, expanding in a direction from a front side to a back side and from a right side to a left side with respect to the keyboard as viewed from a performer depressing the keys; at least three speakers that are disposed in the planar region of the casing, and output tones corresponding to tone signals based on depression of the keys by the performer, wherein the at least three speakers include at least two first speakers disposed on the left and right sides of the front side of the electronic keyboard musical instrument as viewed from the performer, and at least one second speaker disposed on the back side as viewed from the performer separated from the first speakers; a tone signal generation device that generates stereophonic tone signals according to tone information outputted from the keyboard; and a signal processing device that processes the stereophonic tone signals generated by the tone signal generation device according to the arrangement of each of the at least three speakers, respectively, and outputs the processed signals to corresponding ones of the speakers, wherein the signal processing device includes a first localized sound processing section and a second localized sound processing section, wherein each of the first and second localized sound processing sections render processing on left channel signals and right channel signals composing the stereophonic tone signals, wherein the rendered processing comprises a combination of at least one of a delay, a volume level and a phase processing on the left and right channel signals to generate signals, wherein the first localized sound processing section and the second localized sound processing section process the left and right channel signals independent of the processing by the second localized sound processing section and the first localized sound processing section, respectively, to produce different signals outputted to each of the at least three speakers, so as to form sound images outside a region surrounded by the at least three speakers, without depending on listening positions.