Harmonicas

Diatonic Harmonicas

The standard 10-hole major diatonic harmonicas come in all 12 keys of music and allow you to play a complete 7-note major scale of the key of the harmonica. Many additional notes from outside the major scale can be acquired by "bending" certain draw (inhale) and blow (exhale) notes. Most professional players are predominantly diatonic players. Diatonic harmonicas are typically used in blues, rock, country, and folk, but are found in nearly all styles of music. They are sometimes referred to as a "blues harp", "harp", "short harp", or "standard 10-hole".   

Chromatic Harmonicas

The chromatic harmonica has a button on the side, which when NOT used, allows you to play a normal major scale in the key of the chromatic. With the button depressed, you have all the missing half-step notes in-between the major scale notes. This allows you to play in any key and any type of scale. The chromatic is typically used in jazz and classical music, but is found in all styles of music. Bending doesn't work nearly as well on the chromatic as it does on the diatonic harmonica and when used, is used more for a "bending effect".