Module 10: Improvisation II – Bebop LanguageLesson 3advanced⏱ 2 hours + three weeks of drills

Lines over altered dominants and the minor ii–V–i

Altered-scale, diminished and tritone-substitution lines over V7alt and V7b9, and the minor ii–V–i in C, G and F minor, with every tension explained and every resolution to the minor chord worked out.

Why the dominant chord is where the colour lives

Bebop lines over major chords are mostly diatonic; the harmony is stable and the lines stay close to it. The dominant chord is different. It exists to create tension that the next chord releases, and the more tension you put on it, the stronger the release sounds. That is why the richest bebop vocabulary lives on the V chord: the b9 you met in the ii–V–I lesson, the #9 and b13 of the altered sound, the symmetrical patterns of the diminished scale, and the tritone substitute that replaces the whole chord with one a tritone away.

In a minor key this is doubled, because the minor ii–V–i is built from tension from the start: the ii chord is half-diminished, the V chord is almost always altered or b9, and the i chord is a minor 6 or minor-major 7. This lesson gives you lines for all of it. It assumes the theory of minor-key harmony and the altered and half-whole diminished scales from the scales and modes module.

The chords and their tones

The chord-tone check in this module treats the available tensions of a chord symbol as chord tones. For the altered and b9 chords that matters: write the chord as G7alt and the b9, #9 and b13 count as chord tones; write it as G7b9 and the b9 counts while the natural 5th stays. The table shows exactly which notes each symbol owns.

Note the one tension that the G7alt symbol does not list: the b5 (Db). It is in the altered scale and in every altered line players use, but the engine's chord symbol treats it as a scale tone rather than a chord tone, so when a line uses it you will see it in the allow list and in the caption.

Two scales cover almost every dominant situation in this lesson:

• The altered scale (the 7th mode of melodic minor: G altered has the notes of Ab melodic minor) contains the root, 3rd and b7 plus every altered tension: b9, #9, b5 and b13. There is no natural 5th and no natural 9th, which is what makes it sound so dark.
• The half-whole diminished scale contains the root, 3rd, 5th and b7 plus b9, #9, #11 and 13. The natural 13th and natural 5th make it brighter than the altered scale; it is the sound of 7b9 and 13b9 chords.

Which to use depends on the chord symbol and on where the chord is going. Resolving to minor, the altered scale is the first choice because its b13 is the b3 of the coming minor chord. Resolving to major, the diminished scale's natural 13th fits the major 3rd of the I chord. Both work both ways; those are tendencies, not rules.

The minor ii–V–i

Line 1: altered scale descending, C minor

Four bars of the long form in C minor in 5th position. The Dm7b5 bar is an arpeggio to the b7 with an enclosure of that b7 at the top. The G7alt bar runs the altered scale straight down from the #9; the downbeats carry the #9, root, b13 and 3rd, so it behaves exactly like a bebop-scale run even though the scale has only seven notes (it works because the run is one bar long). The b13 of G7alt is the b3 of Cm6, and the line lands on the 6th of the minor chord before settling on the root.

\tempo 132
.
\ts 4 4
:8 7.3{ch "Dm7b5"} 6.2 9.2 8.1 10.1 7.1 8.1 9.2 | 6.1{ch "G7alt"} 9.2 8.2 6.2 8.3 6.3 9.4 8.4 | :8 7.4{ch "Cm6"} 5.4 :4 8.3 :2 10.4 |

Bar 1 (Dm7b5): root, b3, b5, b7, root above, chromatic below the b7, b7, b5. Downbeats: root, b5, root, b7. Bar 2 (G7alt): #9, b9, root, b7, b13, b5, 3, #9. Downbeats: #9, root, b13, 3. The run ends on the #9 a 4th below the b13, and that #9 (Bb) sits a half step above the 6th of Cm6 (A), the first note of bar 3. Bar 3 (Cm6): 6th, 5th, b3 for a quarter, root for a half note. Ending on the 6th or the 9th of a tonic minor is the bebop sound; ending on the root is the arrival.

Practise bar 2 alone until the altered scale descends from any of its notes. The fingering sits in one position (frets 6 to 9) with a single stretch to the 10th fret for the top note of bar 1.

Line 2: a diminished line over G7b9

Over a 7b9 chord the half-whole diminished scale gives the classic symmetrical bebop sound. This line descends the scale from the 5th, with the chord tones (5th, 3rd, b9, b7) on the four downbeats and the scale's other notes between them, then resolves to Cm7: the 13th (E) of the dominant falls to the b3 of the minor chord, which is the resolution that defines the sound.

\tempo 132
.
\ts 4 4
:8 10.1{ch "G7b9"} 9.1 7.1 6.1 9.2 8.2 6.2 5.2 | :8 8.3{ch "Cm7"} 10.4 :4 8.2 :2 8.3 |

Because the scale repeats every three frets, this one-bar run can be moved up or down three frets and still fit G7b9: the pattern you have at the 10th fret works at the 7th and the 13th. That is the practical gift of the symmetrical scales and the reason players collect diminished "cells" rather than long lines. Try the run starting on each of the four chord tones of G7b9 and you will find it is the same fingering four times.

Line 3: the tritone substitute

The tritone substitute for G7 is Db7: the two chords share their 3rd and b7 (B and F, spelled Cb and F in Db7), so a line that outlines Db7 fits over G7 and resolves to C by half step from the root, Db to C. Over a rhythm section playing G7 the Db7 arpeggio supplies the b5, b7, b9 and 3rd of G7, which is pure altered colour; over a rhythm section playing Db7 it is simply the chord. The line below writes the symbol as Db7 so that the check reads the notes as chord tones. Play it over both.

\tempo 140
.
\ts 4 4
:8 7.3{ch "Dm7"} 6.2 5.1 8.1 7.1{ch "Db7"} 9.2 6.2 6.3 | :4 5.3{ch "Cmaj7"} :8 7.3 5.2 :2 8.2 |

Heard against G7, the four notes of beats 3 and 4 are the 3rd, b9, b7 and b5 of the dominant, all strong bebop tensions, and the b5-to-root resolution is the same half-step fall as b9 to 5th, one string lower. The tritone substitution lesson in the second harmony module develops the theory; here the point is the line.

Line 4: resolving to minor in G minor

The short form of the minor ii–V–i in G minor, in 3rd position, with no chromatic notes outside the chord symbols at all: everything is a chord tone or a listed tension. The Am7b5 arpeggio rises to the b7, the D7alt line falls through 3rd, b9, b7 and b13, and the b13 (Bb) is the b3 of the coming Gm6, so the resolution lands on the root with the b3 already in the ear. The phrase ends on the 6th of Gm6.

\tempo 140
.
\ts 4 4
:8 7.4{ch "Am7b5"} 5.3 4.2 3.1 7.2{ch "D7alt"} 8.3 5.3 3.3 | :4 5.4{ch "Gm6"} :8 3.3 3.2 :2 5.2 |

This is the resolution to memorise: b13 of the V chord equals b3 of the i chord. Combined with the b9-to-5th and 3rd-to-root resolutions you already have, it gives you a voice-leading route from every altered tone into the minor chord.

Line 5: the altered arpeggio in F minor

The same idea in F minor, in 3rd position, written as an "altered arpeggio": 3rd, b9, b7, b13 of C7alt, falling in 3rds like an ordinary arpeggio but made of the altered tones. The Gm7b5 bar is the plain arpeggio from the root, and the Fm6 bar resolves the b13 (Ab) through the 9th of F minor to the root.

\tempo 140
.
\ts 4 4
:8 5.4{ch "Gm7b5"} 3.3 6.3 6.2 5.2{ch "C7alt"} 6.3 3.3 6.4 | :8 5.4{ch "Fm6"} 3.4 :4 6.4 :2 5.3 |

Play Lines 4 and 5 back to back and you have the two basic shapes of the altered sound over a short minor ii–V–i: descending through the altered tones to the b13, and then onward into the tonic minor. Transpose both to C minor and D minor; the four-key table above gives the chords.

The altered scale in position

To improvise rather than quote, you need the altered scale under the fingers as a shape, not only as a line. Here is G altered in 2nd–3rd position and a two-octave descent through it.

\tempo 120
.
\ts 4 4
:8 3.1{ch "G7alt"} 6.2 4.2 6.3 4.3 3.3 6.4 5.4 | 3.4 6.5 4.5 7.6 6.6 4.6 3.6 1.6 | :1 3.6 |

Map the same scale a 4th higher for C7alt and a 4th higher again for F7alt in the scale finder, and compare the shape with Ab, Db and Gb melodic minor: identical notes, and if you already know the melodic minor fingerings from the scales module you already know the altered fingerings.

Choosing the colour

A rough guide for the V chord, to be overridden by your ear and by what the pianist plays:

The last row is a reminder that the same line can serve several chords. The Db7 arpeggio of Line 3 is an altered line over G7, a plain line over Db7, and a diminished-flavoured line over G7b9; what changes is what the rhythm section plays under it, not what you play.

Exercises

1. Resolution drill. Over every dominant around the cycle of 4ths, play the b9 and resolve it to the 5th of the next chord, then the b13 resolved to the b3 of the next minor chord, then the 3rd resolved to the root. Quarter notes at 72 bpm, saying the degrees.
2. Altered descent from any note. Over a G7alt vamp, start the altered scale on each of its seven notes and descend for one bar, then resolve to a note of Cm6. Which starting notes put chord tones on all four downbeats? (Line 1 shows one answer.)
3. Diminished cell up the neck. Take the bar of Line 2 and play it starting at the 10th, 7th, 4th and 13th frets over G7b9. Then do the same for C7b9 and F7b9.
4. Tritone sub over the rhythm section. Record or loop a plain G7 to Cmaj7 and play Line 3 over it; then loop Db7 to Cmaj7 and play the same line. Hear how the line's meaning changes with the bass note.
5. Three keys. Lines 1, 4 and 5 in C minor, G minor, F minor and D minor. Write the degrees first; rebuild, do not slide.

Quiz