The NP-31 can be transposed 6 semitones up or down as follows:
Transposing up:
Press and hold the [DEMO] and [METRONOME ON OFF] buttons, then press any key between middle C (C3)and the F# (F#3) above middle C.
Transposing down:
Press and hold the [DEMO] and [METRONOME ON OFF] buttons, then press any key between middle C (C3)and the F# (F#2) below middle C.
Note: The NP-30 cannot be transposed an octave.
Transposing back to standard pitch:
Press and hold the [SONG] and [GRAND PIANO] buttons, then the middle C (C3) key.
Transposition and tuning can be reset to standard pitch by performing a factory reset:
Hold down the highest white key while turning on the power.
