Harmonica Types

There are two main types of harmonicas

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 semi-tone 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.

The chromatic harmonica is mostly used for jazz, classical, and pop music.

 

Diatonic Harmonica:-

The diatonic harmonica mostly used in blues, rock, country and folk.

The diatonic doesn't have easy access to all the possible notes like the chromatic harmonica but many of the notes that are not naturally found can be acquired by "bending" certain draw (inhale) and blow (exhale) notes.

It is the "bending" sound of the diatonic that attracts most people to it.