Harmonica mouth-organ

Diatonic Harmonica

Strictly speaking, "diatonic" denotes any harmonica that is designed for playing in only one key (though the standard "Richter-tuned" diatonic can be played in other keys by forcing its reeds to play tones that are not part of its basic scale). Depending on the region of the world, "diatonic harmonica" may mean either the tremolo harmonica (in East Asia) or blues harp (In Europe and North America). Other diatonic harmonicas include octave harmonica.









Chromatic Harmonica

The chromatic harmonica has a button on the right side which when NOT pressed in, allows you to play a standard major scale the key of the chromatic (typically, the key of "C"), and with the button depressed, gives you all the half-steps or flat notes . This creates a 12-note chromatic scale (all the notes possible in Western Culture music -- like the white and black keys of the piano) and allows you to play any type of scale, in all 12 keys.








Tremolo harmonica


The tremolo harmonica's distinguishing feature is that it has two reeds per note, with one slightly sharp and the other slightly flat. This provides a unique wavering or warbling sound created by the two reeds being slightly out of tune with each other and the difference in their subsequent waveforms interacting with each other (its beat). The Asian version, on which all 12 semitones can be played, is used in many East-Asian musics, from rock to pop music.