Module 10: Improvisation II – Bebop LanguageLesson 1advanced⏱ 90 min + two weeks of drills

Bebop scales and chromatic passing tones

The four bebop scales, why one added chromatic note puts every chord tone on a downbeat, and how to run descending bebop lines through dominant, major, minor and ii–V–I situations.

Why an eight-note scale

Play a seven-note scale in straight eighth notes and something awkward happens: because the bar holds eight eighths and the scale holds seven notes, the scale drifts against the beat. Start on the root on beat 1 and by the next bar the root lands on an upbeat; the 3rd, 5th and 7th land wherever they fall. The result is the "running the scale" sound that every teacher warns about, and the reason is purely arithmetic.

Bebop players solved this by adding one chromatic note in the right place. With eight notes, a scale played in eighths repeats every bar, and if the extra note sits between two chord tones, the four chord tones of the seventh chord land on the four downbeats while the tensions and passing tones land on the upbeats. The ear hears the harmony on the strong beats and the chromatic colour on the weak ones. This is the core of the bebop sound, and the four scales in this lesson are its scale-level expression. The lines in the rest of the module use these scales freely, so get them under the fingers now.

The vocabulary you need is from earlier in the course: seventh-chord arpeggios in position from the arpeggio lesson, chord tones on strong beats from chord-tone soloing, and the chromatic approach notes from approach notes and enclosures.

The four bebop scales

Each bebop scale is a familiar seven-note scale plus one chromatic passing tone. The table shows all four from C, next to the scale each one comes from.

• Bebop dominant = Mixolydian + major 7th. The added note sits between the b7 and the root. Use it over dominant 7th chords. This is the most important of the four and most of this lesson is about it.
• Bebop major = major + #5. The added note sits between the 5th and the 6th. Use it over major 7th and major 6th chords; it treats the 6th as a chord tone, which is why it works best when you think of the chord as a 6 chord.
• Bebop Dorian = Dorian + major 3rd. The added note sits between the b3 and the 4th. Use it over the ii chord of a ii–V, where it is really the bebop dominant scale of the V in disguise (more on that below).
• Bebop melodic minor = melodic minor + #5. Use it over the tonic minor chord of a minor key, the m6 or mMaj7 sound.

Say the formula of each scale aloud as degrees before you play it; the lesson on minor scales and the scales and modes module give the parent scales if any of them is rusty.

Bebop dominant: the model

Here is G bebop dominant on the neck in the position you will use for the first exercises. Notice the two adjacent notes a half step apart between the b7 and the root; that pair is the signature of the scale.

Play it descending across two octaves. Descending is the natural direction for this scale; the chromatic step from root to major 7th to b7 falls under the fingers and is what you will hear in recorded solos most often.

\tempo 120
.
\ts 4 4
:8 3.1{ch "G7"} 2.1 6.2 5.2 3.2 5.3 4.3 2.3 | 5.4 4.4 3.4 2.4 5.5 3.5 2.5 5.6 | :2 3.6 r |

Why the added note matters

Now the experiment that explains everything. The first bar below runs G Mixolydian down from the root, seven notes plus a repeat of the root. The second bar runs G bebop dominant down from the same note. Both land on the 5th of Cmaj7 in bar 3. Count the downbeats.

\tempo 120
.
\ts 4 4
:8 3.1{ch "G7" txt "R"} 6.2 5.2{txt "13"} 3.2 5.3{txt "11"} 4.3 2.3{txt "9"} 5.4 | 3.1{ch "G7" txt "R"} 2.1 6.2{txt "b7"} 5.2 3.2{txt "5"} 5.3 4.3{txt "3"} 2.3 | :1 5.4{ch "Cmaj7"} |

In bar 1 three of the four downbeats are tensions: the 13th, the 11th and the 9th are all legal notes over G7, but when they sit on the beat the line sounds like a scale exercise. In bar 2 the inserted major 7th (the F# played on the second eighth) pushes everything after it back by one eighth, so the b7, 5th and 3rd arrive exactly on beats 2, 3 and 4. The tensions and the chromatic note are still there, now on the upbeats where they connect rather than announce. That is the whole trick: one passing tone, placed between the b7 and the root, lines the scale up with the beat.

Two rules follow from it:

1. Start on a chord tone on a downbeat, and the scale will keep placing chord tones on downbeats for as long as you run it. It does not matter which chord tone you start on.
2. If you start on a tension or on an upbeat, something has to give. Either add a second passing tone, repeat a note, or leave a rest, so that the next chord tone lands on a beat. Experienced players do this instinctively; for now, do it consciously.

Start on any chord tone

The scale can start on the root, 3rd, 5th or b7 and still land chord tones on the beats, ascending or descending. The exercise alternates directions through the position: up from the root, down from the root, up from the 3rd, down from the 3rd, up from the 5th. Check the downbeats of each bar against the G7 chord tones.

\tempo 132
.
\ts 4 4
:8 5.4{ch "G7"} 7.4 4.3 5.3 3.2 5.2 6.2 7.2 | 8.2 7.2 6.2 5.2 3.2 5.3 4.3 7.4 | 4.3 5.3 3.2 5.2 6.2 7.2 8.2 5.1 | 7.1 5.1 3.1 7.2 6.2 5.2 3.2 5.3 | 3.2 5.2 6.2 7.2 8.2 5.1 7.1 8.1 | :4 7.1 8.2.2{d} |

Practise this on every dominant chord in the keys you use most: G7, C7, F7, Bb7 and D7 cover most of the standards repertoire and all of rhythm changes. Use the scale finder to map the scale in other positions.

Bebop major over the I chord

Bebop major adds a chromatic note between the 5th and the 6th. Descend from the root in eighths and the downbeats carry the root, 6th, 5th and 3rd, which is a 6 chord. That is why this scale is paired with the major 6 sound: on a Cmaj7 chord the major 7th appears only as an upbeat passing note, on a C6 chord the line sits exactly on the chord. Both are correct; the 6 chord simply describes the sound better.

\tempo 120
.
\ts 4 4
:8 8.1{ch "C6"} 7.1 5.1 4.1 3.1 6.2 5.2 3.2 | 5.3 4.3 7.4 6.4 5.4 3.4 7.5 5.5 | :1 3.5 |

Listen to the #5. Out of context it is a wrong note against a major chord; inside this line it is gone before the ear can object, and the 5th that follows it on the downbeat is strengthened by the chromatic approach. That is the sound of a chromatic passing tone, and the same logic protects every other "wrong" note in this module.

Bebop Dorian over the ii chord

The bebop Dorian scale adds a major 3rd between the b3 and the 4th. Look at the table below and compare the two rows: D bebop Dorian and G bebop dominant are the same eight notes.

That identity is the practical point of the scale. A ii–V is one harmonic unit, and bebop players treat the ii chord as the first half of the V: over Dm7 to G7 you can think "G bebop dominant for two bars" and the ii chord takes care of itself. The added major 3rd (the F# of D bebop Dorian) is the passing tone between the root and b7 of G7, exactly the note you added in the first section.

Over the ii chord itself, be careful. The chord tones of Dm7 do not fall neatly on alternate notes of the eight-note scale, so running the scale blindly on the ii chord will put the 4th or the 6th on downbeats. Treat the minor chord with its arpeggio and tensions on the way up, and switch to the descending bebop dominant run as the V chord arrives. The line below does exactly that: an arpeggio with the 13th and 11th as upbeat passing tones over Dm7, the major 3rd of the Dorian scale as the chromatic link into the G7 bar, and a full descending run over G7 that resolves to the 5th of C.

\tempo 132
.
\ts 4 4
:8 3.2{ch "Dm7"} 6.2 5.1 8.1 7.1 5.1 3.1 7.2 | 6.2{ch "G7"} 5.2 3.2 5.3 4.3 7.4 5.4 4.4 | :4 5.4{ch "Cmaj7"} 7.5 :2 8.6 |

Count the G7 bar: b7 on 1, 5th on 2, 3rd on 3, root on 4. The run started on the b7 on a downbeat and the scale did the rest.

Bebop melodic minor over the tonic minor

The fourth scale serves minor keys. Melodic minor with a #5 added between the 5th and 6th gives, descending from the root, downbeats of root, 6th, 5th and b3: the notes of a minor 6 chord. This is the sound of the tonic minor at the end of a minor tune, where the chord is written m6 or mMaj7.

\tempo 120
.
\ts 4 4
:8 8.1{ch "Cm6"} 7.1 5.1 4.1 3.1 6.2 4.2 3.2 | 5.3 4.3 7.4 6.4 5.4 3.4 6.5 5.5 | :1 3.5 |

Play the C bebop major and C bebop melodic minor runs back to back. One fret, one note, and the whole colour changes while the rhythm and the logic stay identical. That is a useful way to hear why the bebop scales are a system rather than four unrelated patterns.

Putting the scales through a ii–V–I

Here is a four-bar line in F that uses all three major-key bebop scales in turn: the arpeggio of the ii chord with its 9th, the bebop dominant of C7 descending from the 3rd, and the bebop major of F over the I chord written as Fmaj7 and then as F6. Every non-chord tone is on an upbeat, and each is listed in the caption.

\tempo 132
.
\ts 4 4
:8 3.3{ch "Gm7"} 3.2 6.2 5.1 6.1 5.1 3.1 6.2 | 5.2{ch "C7"} 3.2 5.3 4.3 3.3 7.4 5.4 7.5 | 7.4{ch "Fmaj7"} 5.3 5.2 3.1 6.2 5.2 3.2 6.3 | 5.3{ch "F6"} 3.3 7.4 5.4 :2 3.4 |

Analyse it bar by bar, because this is the method you will apply to every line in the module:

• Bar 1 (Gm7). Arpeggio from the b3 up to the 9th, then a step back down to the root through the 9th again. Downbeats: b3, b7, b3, root. The 9th is the only non-chord tone and it is on upbeats both times.
• Bar 2 (C7). C bebop dominant descending from the 3rd. Downbeats: 3rd, root, b7, 5th. The 9th, the chromatic major 7th and the 13th are the upbeats, and the run ends on the 3rd again, a 4th below where it began.
• Bar 3 (Fmaj7). Arpeggio from the 3rd up to the 9th, then F bebop major descending: root, major 7th, 6th, #5. The 9th, 13th and #5 are upbeats; the 6th arrives on beat 4 as a chord tone of the 6 chord the next bar names.
• Bar 4 (F6). The run continues through the 5th, 11th, 3rd and 9th to the root. The 11th and 9th are the upbeats.

Transpose this line to C, Bb and Eb; the ii–V–I vocabulary lesson that follows gives you a system for doing so. For now use the position shapes: the whole line sits between the 3rd and 8th frets and moves to another key by sliding the same fingering.

Chromatic passing tones beyond the scales

The bebop scales are a formalisation of something more general: a chromatic note placed on an upbeat between two notes a whole step apart sounds right in a bebop line, as long as the notes around it are chord tones on the beat. Once you hear that, you can insert passing tones anywhere a whole step occurs in a line, not only between b7 and root or 5 and 6. The next two lessons use this freedom constantly. The three safe places to begin are:

1. Between the root and the b7 of a dominant chord (the bebop dominant note), descending.
2. Between the 5th and 6th of a major or minor 6 chord (the bebop major and bebop melodic minor note), descending.
3. Between the 3rd and the 9th of any chord, descending, which the ii–V–I line above used in bar 2 (the 3rd, then the 9th on the upbeat, then the root).

When you insert a passing tone and the line no longer lines up with the beat, fix it the way bebop players did: add a second chromatic note somewhere else, or drop one scale tone, or start the phrase an eighth later. The rhythm of the chord tones is what the listener follows; everything else is decoration.

Exercises

1. Downbeat check. Play each of the four two-octave runs in this lesson at 80 bpm, tapping your foot on 1 and 3 and saying "chord tone" on every foot tap. If a tap lands on a non-chord tone, you started in the wrong place.
2. Four starting notes. Over G7, start the bebop dominant scale on each chord tone, ascending and descending, as in the exercise above. Then do the same for C7 and F7 in the same position.
3. Change of direction. Play G bebop dominant descending for four notes, then ascending for four, then descending again, and keep the downbeats on chord tones. Each change of direction needs a chord tone on the next beat; find out which notes you have to repeat or skip to make that work.
4. Major to minor. Alternate the C bebop major and C bebop melodic minor runs over a loop of C6 (two bars) and Cm6 (two bars). Record a simple two-chord backing or use the chord dictionary voicings to hear the chords.
5. ii–V–I in four keys. Play the F line above, then move the fingering to C (up a 5th or down a 4th), Bb and Eb. Say the chord symbols as you go.

Quiz