Common Progressions, Transposing and the Capo

Most songs you will write sit on one of four chord skeletons. Knowing them by number lets you write faster, hear changes on first listen, and steal shapes from the whole history of the music without stealing a single song. Then a capo lets you play any of them in whatever key the singer needs.

The four skeletons

Every chord below comes from the key tables in lesson 4. I checked each row against the scale it belongs to.

I - IV - V: the three-chord song

The base of old-time, honky-tonk, bluegrass, early rock and roll and a mountain of protest songs. Common orders are 1 4 1 5, 1 1 4 1 / 1 1 5 5, and 1 4 5 1.

I - V - vi - IV: the radio loop

Four chords, one bar each, around and around. It powers a huge share of pop and modern country choruses. It can sound stale if you lean on it, so let the melody do something surprising over it.

I - vi - IV - V: the doo-wop turn

The 1950s ballad loop, still common in country love songs and slow gospel. Starting the vi chord early in a verse adds a sad tinge that the IV and V lift back out of.

The 12-bar blues

Twelve bars, three chords, usually all played as dominant sevenths. Blues, Western swing, rockabilly and plenty of outlaw country sit on this frame. One chord per bar:

| I7  | I7  | I7  | I7  |
| IV7 | IV7 | I7  | I7  |
| V7  | IV7 | I7  | V7  |

The last bar, the V7, is the turnaround: it kicks you back to the top. On the final pass, end on I7 instead. A common variation, the "quick change," moves bar 2 to IV7 and back to I7 in bar 3.

Transposing

To transpose is to move a song to a new key. You will do this every time a singer says "that's too high." Either of these methods works.

By numbers. Convert the chords to Nashville numbers in the old key, then read them back out in the new key. A song in G that goes G, Em, C, D is 1 6- 4 5. In A, 1 6- 4 5 is A, F#m, D, E. This is the safest method, because it keeps the spellings right.

By counting half steps. Move every chord the same number of half steps. G to A is up two half steps, so Em goes up two to F#m, C to D, D to E. Chord quality never changes: a minor stays minor, a 7 stays a 7.

The capo

A capo clamps across all six strings at one fret. It acts like a movable nut: every open string goes up one half step per fret. Your chord shapes stay the same, but everything sounds higher. Play a G shape with the capo on fret 2 and the guitar sounds an A chord.

Back to the singer who wanted F. Use D-shape chords with a capo on fret 3. D, G, A and Bm shapes sound as F, Bb, C and Dm, exactly the chart in the example. Or use E shapes at fret 1 (E, A, B, C#m shapes sound F, Bb, C, Dm), though B and C#m shapes are barre chords too, so the D-shape option is friendlier.

Capo chart: what key you are in

Find the shape you are playing on the left and the capo fret along the top. I computed each cell by counting half steps up from the shape and checked it against the low E string fret ladder in lesson 1.

Reverse chart: I need this key

Capo habits that save grief: put the capo just behind the fret wire, not on top of it or in the middle of the space, or the strings buzz and go sharp. Check tuning after you clamp it, because a capo can pull strings a little sharp. And on a number chart, write the real key at the top, plus the capo note for guitar: "Key Bb (gtr capo 3, G shapes)." The bass player and the piano player need the real key, not your shapes.

Picking the key

The right key is the one where the singer's highest and lowest melody notes both sound good. Sing the lowest note of the verse and the highest note of the chorus. If the top strains, drop the key. If the bottom turns to mumble, raise it. Change one half step at a time and the capo makes each test take ten seconds.