Plural pieces of music data (performance data) each corresponding to each
of plural music pieces are stored in a rewritable external storage device
25. Further, tone range restriction data indicating a sound generable
range of a tone is stored in the external storage device 25 as associated
with each piece of performance data or each piece of tone color data for
controlling a tone color of a tone. A CPU 21 transposes the music piece
corresponding to the selected performance data by the inputted
transposition amount by the program process. In case where a part of the
pitch of the transposed music piece is outside the sound generable range
indicated by tone range restriction data corresponding to the selected
performance data or to the selected tone color data, the transposition
amount of all of or a part of the music piece including at least a note
corresponding to the aforesaid part of the pitch is changed. Accordingly,
a sound generable range is changed depending upon a music piece or
according to a taste of a user even if a tone is generated with a same
tone color.