When it comes to easy playability, affordability and portability, it’s hard to beat a harmonica. Despite their modest size and cost, harmonicas are capable of producing an amazing array of tones, and this versatility is reflected in the music genres in which the mighty little mouth harp plays a part. From the more obvious categories such as blues, country, and rock to more surprising musical territory such as jazz and classical music, the harmonica with its often human-like voice easily fits in.

In this guide, we’ll look at the many types of harmonicas that are available and pinpoint those that make sense for beginners as well as harp players and other musicians looking to expand their repertoires.

Types of harmonicas

Though there are a number of specialty harmonicas, the three most common varieties fall into one of three categories based on how they are tuned: diatonic, chromatic, and tremolo harmonica. We’ll focus mainly on these while touching on a few of the less common harmonica types.

If you want to dive right in, you can browse the huge Musician’s Friend selection of all types of harmonicas here.

Diatonic harmonicas

The most common type of harmonica you’ll encounter in pop, blues and folk music—diatonic harmonicas are designed to play in a specific key. That said, overblowing and note-bending techniques plus playing in alternate “positions” makes it possible to play a diatonic in keys and modes other than its “official” key. A couple of players, Howard Levy and Carlos Del Junco, have developed an overblowing technique with which they play chromatically using a humble 10-hole diatonic harp.

Blues harp players usually perform in what’s called “cross harp” or “second position.” This involves playing a harmonica that’s tuned to a perfect fourth below the key the music’s written in. If a song is in the key of C, an F harmonica will be used. Most blues use the notes of a pentatonic scale, and playing a G-tuned harp gives you access to notes that complement the pentatonic C scale, especially on draw notes—those on which you inhale to produce those wailing “bent” notes that are a cornerstone of blues harp technique.

There are a number of other positions that skilled harp players use to mesh with other instruments and create various effects. Cupping your hands around the harp and using your tongue to block and unblock holes are some of the ways to create rhythmic chordal effects and tones. You’ll find numerous online resources as well as harmonica books and tutorials that explain these techniques in detail. We’ll make several recommendations on excellent harp tutorials below.

A diatonic harmonica’s simplicity makes it a great choice for the beginner. Most harmonica teachers recommend starting out with a 10-hole diatonic harmonica tuned to the key of C.

As you shop the huge selection of harmonicas at Musician's Friend, you’ll come across many variations on the basic diatonic harmonica.Take for example the Lee Oskar line of harmonicas. Designed by the harp player who gave the band War its distinctive sound, some Lee Oskar models are tuned to minor and other non-standard scales. Many harp players like their bright, penetrating sound and the fact the company sells replacement reed plates so you can refurbish an older harp rather than buying a new one.

Most harp players end up with a collection of diatonic harmonicas from various makers in a range of keys. Since their cost is far more modest than say, guitars, building a collection of harps to suit various styles of music and situations is easy to do. We recommend you try a number of different models to discover which instruments suit your playing style and the sound you’re going for.

Chromatic harmonicas

Most chromatic harmonicas have a button-activated lever that directs air to two separate reed plates that include all the notes in the 12-tone western scale. With sufficient skill, you can play just about any scale or mode using the chromatic’s “gear shift.”

The larger reeds in the chromatic are somewhat harder to bend and overblow than their diatonic counterparts. But thanks to their heft, the chromatic is capable of producing some very rich-sounding chords and effects. Many blues harp players such as Little Walter, Rod Piazza and George “Harmonica” Smith have used chromatics to generate fat tones that have led to the blues fan term “Mississippi saxophone.”

In the hands of a virtuoso like Toots Thielman, a chromatic harmonica can be used to play complex jazz scales with lightning-fast melodic runs that you’d more likely associate with a saxophone. Stevie Wonder is another master of the chromatic harmonica. His harp solos on “Isn’t She Lovely” offer a master class in overblowing techniques.

Chromatic harmonicas are more difficult to play than diatonics. Therefore, we recommend beginning with a diatonic and stepping up when you’re ready to take on a more challenging instrument. Learning to first play in all positions on a diatonic will allow you to graduate more easily to a chromatic. Even though chromatics are nominally tuned to the key of C or G, in actuality, if you learn all the appropriate scales and positions, you can play virtually any music that uses the standard 12-tone scale.

Tremolo harmonicas

Tremolo harmonicas, also sometimes referred to as “echo” harmonicas, produce their distinctive warbling sound through the use of two reeds per note, one tuned slightly sharp, the other slightly flat. The difference between the waveforms created by the paired reeds causes the beating effect that’s somewhat akin to the shimmering sound of a 12-string guitar that has paired strings tuned an octave apart.

Chromatic tremolo harmonicas are popular in Asian rock and pop music. Diatonic tremolo harps are sometimes used in folk and pop music, and produce a rustic tone that’s ideal for playing cowboy songs like “Red River Valley” around the campfire.

Specialty harmonicas

Though far less common than the types we’ve already discussed, specialty children's harmonicas are popular for use in harmonica ensembles and orchestral settings. Here’s a brief overview:

Chord harmonicas

These are usually large instruments that can produce up to 48 different chords and are typically laid out in blocks of four-note clusters. Each note usually has two reeds tuned an octave apart. Chord harmonicas provide rhythmic and melodic support in harmonica ensembles.