First Things First: Types of Harmonicas
Harmonicas come in a wide range of varieties, the majority of which have fallen out of common usage. The focus here will be on the ones that you're most likely to run across as you learn to play.
Diatonic Versus Chromatic
The diatonic harmonica is the most popular and the one most commonly used, since it has traditionally been an inexpensive and widely available instrument. It's by far the most often used instrument in blues, rock, country, and traditional folk music.
The diatonic harmonica has ten holes, each of which produces one note when blown and another note when drawn. The instrument has a basic range of nineteen notes, rather than twenty, because the 2-hole draw and the 3-hole blow notes are the same. Beyond that, many other notes can be produced on the harmonica using note-bending techniques. (More on note bending in Chapter 5.) The diatonic harp does not contain every note of the scale — rather it is based on a pentatonic, or five-note, scale utilizing equal temperament tuning.
Equal temperament tuning is a system by which the octave is divided into twelve equal half steps. It was designed to help different types of instruments with different tuning systems be able to play together and sound in tune with each other. Most Western-scaled instruments use equal temperament tuning.
The chromatic harmonica is based on the full twelve-note scale, giving it more reeds and therefore more range. It also has a device for changing key, usually a plunger that blocks certain holes and reeds when depressed. The diatonic harmonica has no such device, so one must purchase different harps to play in different keys.
FIGURE 1-1: Blow notes and draw notes of a diatonic harmonica/chromatic example
Other Types of Harmonicas
There are many other types of harmonicas, including:
Octave harmonicas: These banana-shaped harmonicas have two holes stacked vertically for each note. The notes are tuned an octave apart, which gives the instrument a rich chorus sound similar to a twelve-string guitar.
Bass harmonicas: These bad boys are about a foot and a half long! They have the standard ten holes (just a lot bigger) and take special breathing techniques to play because it takes so much air to move the big reeds. They were popular and used quite a bit in music from several decades ago, but are not in wide use today.
Miniature harmonicas: At the other end of the spectrum are the miniatures. These teensy harps are manufactured to the same standards as their big brothers. They only have four holes and play in the high soprano range, but it's still possible to get good bends and trills on them, and although they're so tiny, their holes are almost as big as on a regular-size harp.
However, the two types that are most commonly used and have become most prominent in modern music are the diatonic and the chromatic harmonica. And the one that this book will concentrate on is the diatonic.