The Structure of the Harmonica
Layout of the tones
The layout of the tones follows a simple rule
The layout of the tones of a harmonica differs slightly depending on the model of the instrument. In some models, the notes are arranged in order: C, D, E, F, G, A, B, C. However, this is not the case for many models. These layouts follow a simple rule.
Usually, the principle is that C, E, and G are blow notes, and D, F, A, and B are draw notes. First, the positions of C, E, and G are determined, and then D, F, A, and B-the draw notes-are added between them. If the draw notes are added between the blow notes, then the order is C, D, E, F, G, A, C, B, meaning that only the C and B notes at the end have switched.
With this as the basis, when D, F, A, and B are inserted on the left, among the low notes, and on the right, among the high notes, the order becomes mixed up. Consider, however, the way in which the instrument is played. Alternating blow and draw notes are easier to play, and, with practice, such a layout will not seem strange.
Basically, blow-note C, E, and G and draw-note D, F, A, and B alternate with one another, but the layout depends on the make and model. Resultantly, harmonicas have various sound ranges.