1. Maj 7 chords are made of 1, 3, 5, 7 of the major scale.
It is often desirable to add color to chords using chord extensions that may or may not be indicated in the chord symbol. On major seventh chords, the typically available extensions are the 9, 13 and sharp 11.
Knowing how a chord is functioning in a key often reveals which of the color extensions will sound most logical. This is where harmonic analysis and knowing modes will come in handy.
For instance: If C maj 7 is functioning in the key of C as I (one) maj 7 its corresponding scale will be the IONIAN MODE. the 9 and 13 will more than sound fine as extensions most of the time but the #11 will sound out of place unless it is accomplished artfully.
If C maj 7 is functioning as the IV maj 7 chord (in the key of G) or flat II maj 7 (in the key of B), flat III maj 7 (key of A) or flat VI major 7 (key of E), the function of the chord will be of a LYDIAN nature and the #11 will sound more logical because the relationship between the sharp 11 of each of the IVmaj 7, bIImaj 7, bIIImaj7, and bVI maj7 chords are already in the key.
2. Minor 7 chords are made of 1, flat 3, 5, flat 7
(C-7, Cmi7, Cm7)
Color extensions available for minor 7th chords are most typically the natural 9, 11 and sometimes the 13.
To add color extensions to minor 7th chords, harmonic analysis is again helpful: If C-7 is
functioning in a key as the II-7, meaning that the key is Bb or it is functioning as part of a
"II-7 V7 I" sequence), the DORIAN MODE will be a scale of notes that will be most common. In this case, the most logical sounding chord extensions will be 9 and 11 as long as they do not clash with the melody. The 13 (sixth degree) can often be a very expressive extension but must be handled artfully or it will sound incorrect.
If the minor 7th chord is functioning in a key as III minor (PHRYGIAN MODE), the 11 will be the first logical choice for color extension and the 9 is not recommended because in the phrygian mode, the second degree of the scale is a half step from the root and the sound of a flat nine on a minor 7th chord is not desirable in most cases. The sixth degree is also flatted and that too is usually not desirable on a minor chord.
If a minor 7th chord is functioning in a key as VI minor 7th, it is of the AEOLIAN MODE.
The aeolian mode has a natural second degree and fourth degree of the scale and both of those will make logical choices for chord extensions most of the time as long as they do not clash with the melody.
3. Unless otherwise indicated, Dominant 7th chords are 1, 3, 5, flat 7
Dominant 7th chords can often have a flat 5 or sharp 5 but it will usually be indicated in the chord symbol if the 5th is flatted.
Dominant 7th chords have many possibilities for chord extensions to add color and richness. The most common possibilities are: natural nine, sharp 11, 13, flat 9, sharp 9 and flat 13.
A dominant chord leading into a minor chord will most often lean toward altered nines (flat nine or sharp nine). A dominant chord resolving to a major chord will usually sound most logical with a natural nine and natural 13.
- The term "logical sounding" will most often be determined by the commonalties and differences between the chords and the melody. The more common tonalities you maintain between one chord to the next, the more logical and smooth the progression through the chord changes will be. However, this is a very good opportunity for an advanced improviser to use the opposite for his/her expression. In either case, the listener's ear will usually make a comparison of that which IS played with that which is most "logical sounding" and that factor is a useful tool to the improviser or composer in his/her harmonic expressions.
The melody of a piece of music will often reveal which extension will be most appropriate to use for added color and richness.
If a flat nine is used in the melody or chord symbol, the sharp nine is also usually a member of that chord scale. If a sharp nine is indicated in the melody or chord symbol, the flat nine is also usually a member of that chord scale.
If a dominant 7th chord is resolving to I major, the most common choice of chord scale will be MIXOLYDIAN. If it is resolving to any major chord other than the I (one) chord the most common choice will probably be that of a LYDIAN FLAT 7 chord scale (major scale with a sharp 4 and flatted 7th degree).
4. Mi 7 flat 5 chords are 1, flat 3, flat 5, flat 7
(C-7b5, Cmi7 b5) or (C half diminished - circle with a line through it)
The most common color tone extension on minor 7 flat 5 chords is the 11. The 9 can sometimes be artfully made into a natural 9 to replace the flat 9.
5. diminished 7 chords are 1, flat 3, flat 5, double flat 7
(C small circle 7)
6. augmented 7th chords (dominant) are 1, 3, #5, and flat 7
The most common color tone for extensions on an augmented dominant chord is the 9 and sharp 11.
7. minor-major 7th chords are 1, flat 3, 5, and major 7
The most common color tone for extensions on a minor-major 7th chord is the 9 and 11.
8. (sus) 4 chords are 1, 4, 5 and flat 7.
(sus is an abbreviation for suspended)
The most common color tone extension on a sus4 chord is the 9.
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About John Mark Piper
John Mark Piper is a professional vibraphonist/drummer/composer and teacher residing in the Dallas, Texas area. Piper served as artist, clinician, endorsee and consultant for Musser/Ludwig percussion instruments from 1996 to 2002 and is the designer and creator of the Musser/Piper vibraphone.