Chromatic Harmonicas

These models incorporate the full chromatic scale and allow the player to play in any key using one harmonica. Chromatic models provide the complete 12 note octave with all sharps and flats. Each hole contains four reeds: two are for natural notes and two for chromatic notes. The reeds for chromatic notes are brought into operation by pushing a slide button on the side of the harmonica. This closes off the air flow from one set or reeds and permits the other set to vibrate freely. The preferred instrument for Jazz and Classical, chromatic harmonicas are also used for Blues and Popular Music.

Diatonic Single Reed Models

These models include some of the most popular harmonicas and are used in Blues, Folk, Country, and Rock. All feature reeds which are tuned to produce the natural notes of the scale without any additional sharps and flats. Most are ten hole instruments with the four middle holes comprising a complete eight note octave, and the holes an either side extending the scale and permitting chord playing. These models are capable of producing the expressive effects of bending and overblowing.

Tremolo harmonicas

Tremolo harmonicas are Diatronic models constructed with double holes, each containing two reeds tuned to the same note, one tuned slightly higher than the other. Since both reeds are either blow or draw, when played both will sound together - the slight difference in tuning creating a beautiful vibrating or tremolo effect. Tremolo models are popular for ballads and gospel music, as well as for Latin, Asian, European and other international folk styles.

Some Octave harmonicas

Octave harmonicas are similar to tremolo models in reed layout and musical range. Instead of having reeds tuned to the same note, however, each double hole has one reed tuned an octave apart from the other.
The resulting sound is stronger and full bodied, but without the tremolo effect.
This is the harmonica equivalent of a twelve-string guitar and is ideal for regional and international styles like Cajun, Old-Time and Irish music.