An electronic musical instrument according to one embodiment includes: a sound source configured to generate a first sound signal and a second sound signal in accordance with an instruction signal for instructing to produce a sound; a first output unit configured to output a third sound signal containing the first sound signal and the second sound signal at a first sound volume ratio; and a second output unit configured to output a fourth sound signal containing the first sound signal and the second sound signal at a second sound volume ratio that is different from the first sound volume ratio.

An electronic musical instrument according to one embodiment includes: a sound source configured to generate a first sound signal and a second sound signal in accordance with an instruction signal for instructing to produce a sound; a first output unit configured to output a third sound signal containing the first sound signal and the second sound signal at a first sound volume ratio; and a second output unit configured to output a fourth sound signal containing the first sound signal and the second sound signal at a second sound volume ratio that is different from the first sound volume ratio.

A modulating keyboard having a relative transposition in an electronic keyboard musical instrument and a method for relative transposition are provided. An instrument includes a keyboard having a plurality of first keys alternating with a plurality of second keys and a modulator system coupled to the keyboard. The modulator system is configured to assign note values to each of the first keys and the second keys such that, for each key signature, notes associated with the key signature are assigned to the plurality of first keys and notes not in the key signature are assigned to the plurality of second keys.

A modulating keyboard having a relative transposition in an electronic keyboard musical instrument and a method for relative transposition are provided. An instrument includes a keyboard having a plurality of first keys alternating with a plurality of second keys and a modulator system coupled to the keyboard. The modulator system is configured to assign note values to each of the first keys and the second keys such that, for each key signature, notes associated with the key signature are assigned to the plurality of first keys and notes not in the key signature are assigned to the plurality of second keys.