Abstract: A method of coupling diatonic harmonicas that increases the musical range of the diatonic harmonicas being coupled. Diatonic harmonicas are stacked and secured together by a clamping mechanism in order to form an instrumental assembly that is more versatile than a single diatonic harmonica. An ideal key is first determined according to a selected musical piece. The ideal key provides a foundation from which an initial harmonica and a subsequent harmonica are selected from a plurality of harmonicas. Each of the plurality of harmonicas is tuned in a musical key that is either major or minor. The musical key of the initial harmonica is determined according to the ideal key, while the musical key of the subsequent harmonica is determined from the chromatic scale. Once the initial harmonica and the subsequent harmonica are selected, they are coupled together by the clamping mechanism.