Abstract: 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.