Module 8: Voicings II: drop-2, drop-3 and rootless shapesLesson 4advanced⏱ 90 min + three weeks of daily drills

Voice leading through ii–V–I, turnarounds and the cycle

Learn the minimal-movement principle, the inversion rules that follow from it, and apply them to the ii–V–I, the I–vi–ii–V and iii–VI7–ii–V turnarounds and the cycle of fourths in every key.

Why voice leading is the real skill

Knowing forty shapes does not make a comping player. Listen to a pianist comp a ii–V–I and you hear four or five voices that each move as little as possible; the chords change, but the hand barely does. That is voice leading, and on guitar it is the difference between a chordal accompaniment that sounds like a sequence of unrelated grips and one that sounds like a small horn section breathing together.

You already have the raw material: every inversion of every seventh chord on five string sets from lessons 1 to 3. This lesson gives you one principle and three rules that come from it, then drills them through the progressions that make up most of the standard repertoire. The voice-leading assistant on the chord-dictionary page applies the same principle automatically, and you should use it to check your own choices.

The minimal-movement principle

When one chord changes to the next:

1. A note that belongs to both chords stays where it is (a common tone).
2. Every other note moves to the nearest note of the new chord, by a half step or a whole step if at all possible.
3. The total movement, in semitones, should be as small as the shapes allow.

Here is the same ii–V in two ways. The first uses the root-position shape of both chords; the second uses the nearest inversion. Count the frets each finger travels.

\tempo 92
.
\ts 4 4
:2 (5.5 7.4 5.3 6.2){ch "Dm7"} (10.5 12.4 10.3 12.2){ch "G7"} | (5.5 7.4 5.3 6.2){ch "Dm7"} (5.5 5.4 4.3 6.2){ch "G7"} |

In the second bar, voice by voice from the bottom: D stays (0 semitones), A falls to G (2), C falls to B (1), F stays (0). Three semitones of total movement, against something like twenty in the first bar. Both bars are "correct" chords. Only one of them is music.

Rule 1: roots moving up a 4th

Most chord changes in jazz move the root up a perfect 4th (equivalently, down a 5th): ii to V, V to I, vi to ii, I to IV, and every step of the cycle of fourths. For that motion the two chords always share two notes, and on one string set the nearest inversion is fixed:

Whatever the inversion, the common tones between two chords a 4th apart are always the root and 3rd of the first chord, which become the 5th and 7th of the second. The other two voices (the 5th and 7th of the first chord) each fall by a step to become the next chord's root and 3rd.

Apply it twice and you have the ii–V–I of lesson 1: ii root to V second to I root, ii first to V third to I first, and so on. Apply it twelve times and you have the cycle of fourths, which is the last section of this lesson.

Rule 2: roots moving down a 3rd

I to vi (Cmaj7 to Am7) and iii to I (Em7 to Cmaj7) move the root down a minor 3rd, and the two chords share three notes. Only one voice moves, by a whole step. The rule is: the inversion number goes up by one. Cmaj7 in root position (C–G–B–E) goes to Am7 in first inversion (C–G–A–E); the B falls to A and nothing else moves.

\tempo 84
.
\ts 4 4
:2 (3.5 5.4 4.3 5.2){ch "Cmaj7"} (3.5 5.4 2.3 5.2){ch "Am7"} | (7.5 9.4 5.3 8.2){ch "Cmaj7"} (7.5 7.4 5.3 8.2){ch "Am7"} | (10.5 10.4 9.3 12.2){ch "Cmaj7"} (10.5 10.4 9.3 10.2){ch "Am7"} | (2.5 2.4 0.3 1.2){ch "Cmaj7"} (0.5 2.4 0.3 1.2){ch "Am7"} |

Rule 3: when the rules conflict, follow the bass

A turnaround contains both kinds of motion, so the inversions you arrive at are not your choice: they are decided by where you start. Follow the chain and you will end the turnaround in a different inversion from the one you began with, usually lower on the neck. That is normal. Over several choruses you can let the turnaround walk down the neck, or jump back up to the starting position at the top of the form. The one thing not to do is break the chain in the middle to get back to a favourite shape.

The I–vi–ii–V turnaround

Cmaj7–Am7–Dm7–G7 is the most common two-bar unit in standards: the last two bars of most A sections, the intro to half the songbook, and the "rhythm changes" A section stripped to its bones. Start from the root position I chord and the rules produce this:

\tempo 110
.
\ts 4 4
:2 (3.5 5.4 4.3 5.2){ch "Cmaj7"} (3.5 5.4 2.3 5.2){ch "Am7"} | (3.5 3.4 2.3 3.2){ch "Dm7"} (2.5 3.4 0.3 3.2){ch "G7"} | :1 (2.5 2.4 0.3 1.2){ch "Cmaj7"} | :2 (2.5 2.4 0.3 1.2){ch "Cmaj7"} (0.5 2.4 0.3 1.2){ch "Am7"} | (3.5 3.4 2.3 3.2){ch "Dm7"} (2.5 3.4 0.3 3.2){ch "G7"} | :1 (2.5 2.4 0.3 1.2){ch "Cmaj7"} |

In the second version the Am7 to Dm7 move breaks the "two common tones" pattern: Am7 in root position (A–E–G–C) to Dm7 in third inversion (C–F–A–D) moves every voice, because the first-inversion Dm7 that Rule 1 asks for sits twelve frets higher. When the ideal inversion is out of reach, take the nearest available one and move every voice by step, as here. Smooth step motion in all four voices is the second-best outcome and still sounds good.

The same chain on the other string sets, in two more keys:

\tempo 110
.
\ts 4 4
:2 (5.4 7.3 7.2 7.1){ch "Gmaj7"} (5.4 7.3 5.2 7.1){ch "Em7"} | (5.4 5.3 5.2 5.1){ch "Am7"} (4.4 5.3 3.2 5.1){ch "D7"} | :1 (4.4 4.3 3.2 3.1){ch "Gmaj7"} | :2 (5.5 7.4 3.3 6.2){ch "Bbmaj7"} (5.5 5.4 3.3 6.2){ch "Gm7"} | (3.5 5.4 3.3 4.2){ch "Cm7"} (3.5 3.4 2.3 4.2){ch "F7"} | :1 (1.5 3.4 2.3 3.2){ch "Bbmaj7"} |

The iii–VI7–ii–V turnaround

Replace the I with iii (Em7 for Cmaj7: they share three notes, so the change is nearly invisible) and make the vi a dominant (A7 instead of Am7, so that it pulls towards Dm7), and the turnaround becomes Em7–A7–Dm7–G7. Now every root moves up a 4th, so Rule 1 applies four times in a row and the chain alternates between two inversions: root/second/root/second or first/third/first/third. The hand drifts down the neck by about two frets per bar.

\tempo 110
.
\ts 4 4
:2 (5.5 5.4 4.3 5.2){ch "Em7"} (4.5 5.4 2.3 5.2){ch "A7"} | (3.5 3.4 2.3 3.2){ch "Dm7"} (2.5 3.4 0.3 3.2){ch "G7"} | :1 (2.5 2.4 0.3 1.2){ch "Cmaj7"} | :2 (7.5 9.4 7.3 8.2){ch "Em7"} (7.5 7.4 6.3 8.2){ch "A7"} | (5.5 7.4 5.3 6.2){ch "Dm7"} (5.5 5.4 4.3 6.2){ch "G7"} | :1 (3.5 5.4 4.3 5.2){ch "Cmaj7"} | :2 (10.5 12.4 9.3 12.2){ch "Em7"} (10.5 11.4 9.3 10.2){ch "A7"} | (8.5 10.4 7.3 10.2){ch "Dm7"} (8.5 9.4 7.3 8.2){ch "G7"} | :1 (7.5 9.4 5.3 8.2){ch "Cmaj7"} |

Watch the top voice in the second position: G, G, F, F, E. A descending line in the top voice is what a listener actually hears of your comping, and good voice leading produces one without you having to plan it.

\tempo 110
.
\ts 4 4
:2 (5.5 5.4 3.3 6.2){ch "Gm7"} (3.5 5.4 3.3 5.2){ch "C7"} | (3.5 3.4 1.3 4.2){ch "Fm7"} (1.5 3.4 1.3 3.2){ch "Bb7"} | :1 (1.5 1.4 0.3 3.2){ch "Ebmaj7"} |

The cycle of fourths

Twelve dominant chords whose roots move up a 4th each time will visit every key and come home. With Rule 1 the shapes alternate root position and second inversion, and the hand moves down two frets every two chords. When it reaches the bottom of the neck, switch to the other pair (first and third inversion) and the cycle continues from the open position.

\tempo 100
.
\ts 4 4
:2 (10.5 12.4 10.3 12.2){ch "G7"} (10.5 10.4 9.3 11.2){ch "C7"} | (8.5 10.4 8.3 10.2){ch "F7"} (8.5 8.4 7.3 9.2){ch "Bb7"} | (6.5 8.4 6.3 8.2){ch "Eb7"} (6.5 6.4 5.3 7.2){ch "Ab7"} | (4.5 6.4 4.3 6.2){ch "Db7"} (4.5 4.4 3.3 5.2){ch "Gb7"} | (2.5 4.4 2.3 4.2){ch "B7"} (2.5 2.4 1.3 3.2){ch "E7"} | (4.5 5.4 2.3 5.2){ch "A7"} (3.5 4.4 2.3 3.2){ch "D7"} | :1 (2.5 3.4 0.3 3.2){ch "G7"} |

The cycle also runs as a chain of ii–Vs, each a whole step below the last, which is how it appears in many bridges and in tunes that modulate through several keys. Here the ii–V pairs use the first-to-third inversion pairing.

\tempo 100
.
\ts 4 4
:2 (8.5 10.4 7.3 10.2){ch "Dm7"} (8.5 9.4 7.3 8.2){ch "G7"} | (6.5 8.4 5.3 8.2){ch "Cm7"} (6.5 7.4 5.3 6.2){ch "F7"} | (4.5 6.4 3.3 6.2){ch "Bbm7"} (4.5 5.4 3.3 4.2){ch "Eb7"} | (2.5 4.4 1.3 4.2){ch "Abm7"} (2.5 3.4 1.3 2.2){ch "Db7"} | :1 (4.5 4.4 3.3 6.2){ch "Gbmaj7"} |

Using the voice-leading assistant

The chord dictionary page has a voice-leading assistant: type a progression as chord symbols (bar lines optional), choose drop 2, drop 3, shell or rootless and a string set, and it picks for each chord the library voicing that moves the fewest semitones from the previous one. It also prints the alphaTex for its choices, so you can paste the result into your own notes.

Use it in three ways:

• Check your own solution. Work out a turnaround by the rules first, then compare. If the assistant chose differently, count the semitones in both and decide which you prefer; the assistant does not know about register or about the melody of the tune.
• Learn a tune's changes. Type the whole progression of a standard, set a string set, and play through its suggestion slowly. Then do it again on a different set.
• Find the awkward spots. When a progression has a change where no good voicing exists on one set (like the Gbmaj7 above), the assistant's jump shows you where to switch string sets or go to drop 3.

How to practise this lesson

1. Rule drills. Take one chord quality and play chord-to-chord in 4ths across the neck (Cmaj7 to Fmaj7 to Bbmaj7 ...) on one string set, alternating inversions by Rule 1. Then the 3rd-down drill (Cmaj7 to Am7, Fmaj7 to Dm7 ...) by Rule 2.
2. Turnarounds in all keys. I–vi–ii–V first, then iii–VI7–ii–V, from the progression tables, on strings 5-4-3-2, then the other drop-2 sets, then drop 3. Two beats per chord, metronome on 2 and 4.
3. The cycle, daily. Dominants around the cycle on one string set, then m7 chords, then maj7 chords. Three minutes at 100 bpm.
4. A real tune. Choose a standard you know and comp its whole form in one position by the rules, then in another position. Record yourself and listen for jumps.

Quiz