The three most common 7th chords in blues and Jazz music are :

• major 7th (symbol = ) - formed by the 1st, 3rd, 5th and 7th of a major scale
  
  
• dominant 7th - formed by lowering the 7th of a major chord by one semitone
  
  
• minor 7th - formed by lowering the 3rd and 7th of a major chord by one semitone

Audio 12.1

There are many varieties of minor blues. Several examples are included in Jamey Aebersold's Play-a-Long CD and book Volume 2 called Nothin but Blues.

In its simplest form the I7 and IV7 chords are replaced by minor triads or minor 7th chords with the same root.

The V7 chord remains usually dominant in quality but often includes altered notes (most commonly with a b9 and/or #9 added).

Here is the Basic Minor Blues in C minor :

Audio 12.2

Expressed in chord numbers :

Dorian Blues is a basic minor blues in D minor.
The melody consists of notes from the D Dorian and G Dorian modes.

Melody

Play-along in Dm medium tempo - fast (Swing) : sheet music for all instruments.

Play-along in Cm medium tempo - fast (Bossa) : sheet music for all instruments.

Improvise over the minor blues using chord tones only.
Use the extended minor 9th chords for the I and IV chords.
Use a dominant V7 chord with added b9. This is supportive of the minor mood of the song.

Start with practising the routine show below.

Demo

Play-along in Dm medium tempo - fast (Swing) : sheet music for all instruments.

Also practice the same routines for the blues in C minor.
Play-along in Cm medium tempo - fast (Bossa) : sheet music for all instruments.

Improvise over the minor blues using Dorian modes only.
Use the D Dorian mode over Dm7 and the G Dorian mode over Gm7.
Use the G Dorian mode also over the A7 chord. This adds the b9 (Bb) and #9 (C) to the overall sound.
(Using the A Mixolydian mode over the A7 chord is a poor choice for songs in a minor keys as it does not quite fit the minor mood of the song.)

Start with practising the routine shown below.

Demo

(The Bb and C natural in the mode over A7 are resp. heard as b9 and #9 tones,
but you may raise the C to a C#, so that the important 3rd of the A7 chord is included.)

Play-along in Dm medium tempo - fast (Swing) : sheet music for all instruments.

Also practice the same routines for the blues in C minor.
Play-along in Cm medium tempo - fast (Bossa) : sheet music for all instruments.

Scale-tone chords (= chords made up of scale-tones only) of the natural minor scale do not produce an very effective chord progression. To achieve this the 7th note of the natural minor scale was raised by a semitone to form the so-called harmonic minor scale.
This produces a dominant 7th chord on the 5th note of the scale, a strong tension building chords which leads to the tonic chord of the scale.

Audio 14.3

This in turn produces a nice II-V-I chord progression, in Circle of 5ths order, in a distinctly minor mood.

Audio 12.4

The ImM7 chord is not a suitable ending chord for this progression. Therefore either a simple triad chord or a minor 7th chord is used as I chord in this progression. (The notes of the 1m7 chord do not fit into the harmonic minor scale. This therefore produces a short modulation to another scale : the natural minor scale or the Dorian mode).

Also note that the V7 chord in this progression can be extended to a m7^b9 chord. The b9 fits into the harmonic minor scale (Ab in above C harmonic moinor scale).

In general :

• when a dominant 7th chord (V7) is preceded by a minor 7th chord (IIm7) it is part of a major II-V (I) progression.
  In this setting the major scale (and related modes) is appropriate for improvisation.

• when a dominant 7th chord (V7) is preceded by a half diminished chord (IIØ) it is part of a minor II-V (I) progression.
  In this setting the harmonic minor scale (and related modes) is appropriate for improvisation.

chord segment in bars 9 and 10 :

| Im7	| Im7	| Im7	| Im7	|
| IVm7	| IVm7	| Im7	| Im7	|
| IIø(alt)	| V7 (alt)	| Im7	| (V7)	:||

In such cases use the Harmonic minor scale of the I chord for improvisation over IIø - V7.

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BL 12.6 - Blues for Wally

I wrote Blues for Wally, for my first pinao teacher in Adelaide, Walter Lund. He was a much loved character, band leader and arranger for the Channel 9 TV Big Band during the 1970s and an enthusiastic teacher. He continued teaching untill the very day he died. Blues for Wally was performed at a memorial concert after Wally's death.

Melody

Improvise over Blues for Wally using Dorian modes over the Cm7 and Fm7 chords and the C harmonic scale over the G7 chord (G Ab B C D Eb F G).

Swapping 2s and 4s over Blues for Wally (complete improvisation) :

1. Take 1 (10 choruses) - : I play the first 2 bars of each 4-bar phrase, you play the following 2 bars.

2. Take 2 (10 choruses) - : You play the first 2 bars of each 4-bar phrase, I play the following 2 bars.

3. Take 3 (10 choruses) - : I play the first 4-bars, you play the following 4-bars, and so on.
   

4. Take 4 (10 choruses) - : You play the first 4-bars, I play the following 4-bars, and so on.

Use Dorian modes over Cm7 and Fm7 and the C harmonic scale over G7 (G Ab B C D Eb F G).

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BL 12.7 - Quiz

A.
Place the following chords in their correct IIø - V7 - Im order and add the chord qualities (ø, 7, m) :

1. G A D
2. Bb C F
3. A E D
4. F C G
5. B A E

B.
Extend these dominant 7th chords by adding their b9th.

1. F A C Eb
2. A C# E G
3. Bb D F Ab
4. G B D F
5. E G# B D

C.
Having completed question B above : what can you observe when you take each chord root tone away ?

D.
Convert these major scales into harmonic minor scales.

1. D E F# G A B C# D
2. Bb C D Eb F G A Bb
3. F G A Bb C D E F
4. A B C# D E F# G# A
5. G A B C D E F# G

E.
Convert these Dorian modes int harmonic minor scales.

1. C D Eb F G A Bb C
2. A B C D E F# G A
3. Bb C DB Eb F G Ab Bb
4. F G Ab Bb C D Eb F
5. G A Bb C D E F G

F.
Which harmonic minor scales are used over the following Dominant 7^b9 chords.

1. F7^b9
2. A7^b9
3. C7^b9
4. D7^b9
5. E7^b9

Quiz Answers

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BL 12.8 - Exercises

A.
Practise the Dominant 7^b9 chords around the Circle of 5ths as shown below (2 bars for each chord).

Demo


B.
Practise the Harmonic minor scale around the Circle of 5ths in anti-clockwise direction as shown below .

Demo

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BL 12.9 - Lesson Material

Universal Chords Ruler
Harmonic minor scale ruler
Ex.14 - Dominant 7b9 Chords	Demo	2 bars each key
Ex.15 - Harmonic minor scale - p.2	Demo	8 bars each key
Dorian Blues (Dm) - Chords Modes	Melody	Play-a-Long	faster
Dorian Blues (Cm) - Chords Modes		Play-a-Long	faster
Blues for Wally (in Cm)	Melody	PLay-a-long
Swapping 2s on Blues for Wally	Demo	me 1st	you 1st
Swapping 4s on on Blues for Wally		me 1st	you 1st

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Copyright © 2011 Michael Furstner (Jazclass). All rights reserved.