Quality

This is a preview of the educational program A Jazz Improvisation Almanac which is under development for the Outside Shore Music Online School. Feel free to browse this preview and learn what you can from it. For a more completed product, though, check out the original freely browsable jazz textbook, A Jazz Improvisation Primer.

The function of a chord is the most important factor to consider when choosing a scale to use as a basis for improvisation over that chord. There are several components to chord function. These include the quality of the chord and how it relates to the progression. This section discusses how the chord quality affects scale choice.

The quality of a chord is represented by the chord symbol. It specifies whether the basic triad at the root of the chord is major, minor, diminished, or augmented, and it also specifies whether any extensions or alterations are included in the chord. You may review the chapter on Harmony in the unit on Music Theory if you are not clear on how to interpret chord symbols such as G7#11.

The quality of the chord is usually the first factor that improvisors take into account. In fact, it is in many cases the only factor considered. You can select an appropriate scale knowing only the chord symbol, without knowing how it relates to the rest of the progression. In general, a scale is appropriate if it contains all the notes of the chord. For example, consider a C7 chord, which consists of C, E, G, and Bb:

[EXAMPLE]

Any scale that contains these four notes would work over a C7 chord. These scales include C mixolydian, C lydian dominant, C dominant bebop, and C HW diminished:

[EXAMPLE]

The various correspondances between scales and chord types was discussed previously in the chapter on Jazz Scales. In that chapter, I listed chords over which each scale would be appropriate. However, when improvising, one usually has to make the reverse association: given a chord symbol, determine what scale is appropriate. If you list all relationships given in the chapter on Jazz Scales, you get following table:

[EXAMPLE]

Note that the chart often gives several scale possibilities for a given chord. Subsequent sections discuss some of the factors that might lead you to choose one over another. In general, though, the simplest scale suggested by the chart would be the most appropriate one to use. In this context, "simplest" means "most resembling the major or minor scale". For example, while there are several choices for a D7 chord, the D mixolydian is the simplest, and therefore most appropriate. Also, "most appropriate" as used here means "provides the least amount of tension relative to the chord". Sometimes, more tension is what you want, and that is discussed in subsequent sections as well. For now, however, we are concerned with how to select the scale that best reinforces the sound of the chord.

You can use the chart to select scales for each chord in a progression. For example, here is a typical chord progression:

[EXAMPLE]

Here are the scale choices that would be most appropriate for the above composition, according to the chart:

[EXAMPLE]

Here is an example of a melody one might improvise using those scales:

[EXAMPLE]

Note that the improvised melody occassionally uses notes not in the corresponding scales. The scales are only guides. See the chapter on Melody in the unit on Music Theory for more on constructing melodies.

Copyright 2000 Outside Shore Music
Authored by Marc Sabatella

Quality