Chromatic harmonica Chromatic harmonica The chromatic harmonica is a type of harmonica that uses a button-activated sliding bar to redirect air from the hole in the mouthpiece to the selected reed-plate desired. When the button is not pressed, an altered diatonic major scale of the key of the harmonica is available, while depressing the button accesses the same scale a semitone higher in each hole. Thus, the instrument is capable of playing the 12 notes of the Western chromatic scale. The chromatic harmonica can thus be contrasted with a standard harmonica, which can play only the notes in a given musical key.
Pentatonic scale \relative c' { </score> Another construction works backward: It omits two pitches from a diatonic scale. If one were to begin with a C major scale, for example, one might omit the fourth and the seventh scale degrees, F and B. The remaining notes then makes up the major pentatonic scale: C, D, E, G, and A. Omitting the third and seventh degrees of the C major scale obtains the notes for another transpositionally equivalent anhemitonic pentatonic scale: F, G, A, C, D. Omitting the first and fourth degrees of the C major scale gives a third anhemitonic pentatonic scale: