Playing a straight harp song in C? No problem. To play in straight harp, you just match the key of your harmonica to the key of the song. To play in C, use a C harmonica.

Cross harp is a little more complicated – the C harmonica doesn’t play blues in C, it plays blues in G. Why? Because your C harmonica has two chords built into it: a blow chord (C) and a draw chord (G). The draw chord is the basis for your cross harp melody playing, so a little mental math is required to choose a harmonica.

The formula for cross harp is “count to four, alphabetically.”

Let’s say you want to play an E blues. Start on E and count up four notes, alphabetically. That’s “E, F, G, A.” So to play an E blues in cross harp, you need an A harmonica. Got it?

There are seven basic keys which are handy to know, and they’re named using natural notes: A, B, C, D, E, F, G.

Blues Key –> Harmonica Key

A –> D
B –> E
C –> F
D –> G
E –> A
F –> B-flat
G –> C

There are twelve keys total, and most experienced harmonica players have one in each key, to cover all the possibilities. That starts to add up, so if you’re not jamming with other players that much yet, don’t worry about getting a full set. The most common blues keys for guitarists are E, A, D, and G, so you could start with harps in A, D, G, and C (respectively).

Remember, the layout is the same on every diatonic 10-hole harmonica, regardless of key, so what you learn on one, you can transfer to the others. If you’re just getting started, stick with C for awhile, learn to get single notes and bend accurately, then branch out with an A or a G harmonica.

If you’re starting to play more with other musicians, make a chart and some flashcards. Learn what harp you need to play the blues in each key. A little music theory goes a long way!

To play clear melodies, you need to learn to isolate one hole at a time. There are a couple of different ways to play single notes on the harmonica, but the most useful one is the pucker technique.

1. Make big “fish lips” and put the harp in your mouth.
2. Your lips will actually be on the top and bottom coverplates.
3. Firm up your pucker and keep stiff cheeks.
4. You might need to press the harp into your mouth slightly.

Blow into the harmonica and listen. Are you getting a clear single note yet? If not, adjust VERY SLIGHTLY left or right while keeping the harp in your mouth. Press the harp in a little bit and keep your pucker and your cheeks firm.

Experiment with this and you’ll get it. Once you have a clear single note, try alternating between blow and draw on the same hole, then doing the same thing on the next hole over. Have fun!

What Harmonica Should I Buy?
For beginners, I recommend getting a Hohner Special 20 in the key of C, because it has a plastic comb and is more airtight than the wooden comb models. The biggest thing, regardless of the brand, is to get something in the $25-35 range. Any cheaper than that, and it won’t sound as good or play as easily. Hohner is the most popular brand worldwide, but Lee Oskar, Suzuki, Herring, and others also make great harmonicas.

Where Can I Buy a Harp?
If you live in the NC Triangle and you want to shop locally in Carrboro, there are two music stores on Main Street between Wendy’s and the PTA thrift store. The Music Loft is the bigger one, and Carrboro Music is on the corner. In Raleigh and Durham there are also music stores, and most of them will carry a Hohner Special 20 in C.

Online, you can get harmonicas at Amazon or Musicians Friend, but I enjoy supporting the more harp-centric HarmonicaStore.com.

Do I Need Other Keys?
Probably not at first, but eventually, yes. Harmonicas are available in all 12 major keys. After C, you’ll probably want G, A, and D, probably in that order.

G is pitched much lower than your C harp, so those high melodies played on holes 7-10 that sounded shrill on the C will sound more mellow on a G.

This is a big relief, since there are lots of melodies you’ll have to play on 7-10 until you learn to bend consistently on holes 2 and 3. Low harps are also good for practicing your blow bends.

A is also a relatively low-pitched harp, and it allows you to play cross-harp blues in the key of E, which is pretty much the most common blues key for guitar players.

The D is actually higher-pitched than your C harp. This takes a bit of getting used to, but on the plus side, you can count on cutting through the mix, which is not always the case on a low harp! On a D, you can play cross-harp blues in the key of A, which is the second most popular blues key for guitarists.