Blues Harmonica Chord Conversion Chart
Many new players have a hard time figuring out which harmonica to use on different songs. Lets take the C harp as an example because it is the most common one. Since songs are played in a variety of keys, and your C harmonica is limited to this scale, it means you can only play on certain songs with your C harmonica. To play the blues with the C harmonica you need to play the song in the key of G.
The solution is to buy more harmonicas in different keys so that you are prepared for any situation. Serious players will even have harmonica vests allowing you to holster your weapon and grab the next one as needed.
I should point out that we are talking about BLUES HARMONICA and blues-style songs (including rock, pop, and even ska, etc.) that follow simple and similar chord progressions. COUNTRY music and country style harmonica playing can follow a completely different chord chart (like any Neil Young or Bob Dylan song). Country style harmonica playing (in my opinion) is harder to master and has a different style and set of rules for playing that require you to be far more careful and selective with your notes and breathing patterns. Blues harmonica playing is more raw and visceral and allows you play with fewer restrictions and generally produces better results for beginners.
So playing the blues (once you´ve got a bit of technique going) is easier than it looks (or sounds). As long as you have the right harmonica for the key of the song, you can pretty much play whatever you want and make it sound good. It comes down more to the expression and feelings that you can transmit through the instrument. Of course there are many players that go FAR beyond this idea and develop incredible technique and individual note control like John Popper from Blues Traveler…this guy may be the greatest harmonica player on the planet. It is sometimes hard to believe that the sounds and scales he makes can come from a harmonica. There also are a lot of websites out there that will give you every last detail of technical information and theory on harmonica playing. I´m sure some know-it-alls out there might want to criticize my take on the simplicity of blues harmonica, but I still maintain that anybody can easily learn to play a bit of blues.
Cracking the Keycode.
As you can see, the chord chart above shows you the harmonicas you need for the different song keys.
So if the song is played in G, then the harmonica you need to play the blues is C. If the song is played in D, you need a G harmonica, and so on. This works especially great when played over songs with a standard 3-chord blues structure.
A standard blues song in G is played with the chord progression G, C, D. If the blues song is in A, it has a chord structure of A, D, E and you would therefore need the D harmonica. If your blues song is in E, it would have a chord structure of E, A, D and require an A harmonica, and so on. Notice that the harmonica you need is usually the middle chord in the standard blues song progression. If you have a little musical knowledge, it is easy to see the pattern here. But if you´re not sure, ask your guitar player or another musician friend what the middle chord is in the song (blues song), and that will be the key you need for your harmonica.
When building your arsenal of harmonicas, in most cases you will only need to get major harmonica keys (A,B,C,D,E,F,G) but sometimes it is useful to have an F# or a Bb. It really depends on the songs you are going to play. I own 8 harmonicas because I need them all and I bought them as I encountered new songs that needed specific keys
Here is an example from one of my own songs of some blues harmonica playing adapted on a country-folk-rock song called DRAINPIPE. This song is not really a standard blues progression, BUT, it is played in the key of B, and so according the harmonica chord chart, my harmonica is E.