Modal Improvisation

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 term "modal" is somewhat ambiguous. It is used in several different ways by different people, and many musicians have different ideas about what it actually means. In this section, I use a reasonably straightforward definition of "modal": music that uses conventional chords but does not use them in traditional tonal ways. I include music that might otherwise be called "non-tonal" and "pan-tonal" in this discussion. In order to fully understand these terms, you may wish to review the chapter on Harmony from the unit on Music Theory. Basically, though, the implication is that modal music has chords but does use them in dominant/tonic resolutions to establish a sense of key center. For example, the chord progression uses chords in a traditional tonal manner:

[EXAMPLE]

The above examples clearly outlines the key of Eb due to the fact that most of the chords are diatonic to that key, and the presence of the Bb7 resolving to the Eb chord clearly establishes the tonic. This progression is therefore tonal, not modal. Whereas the following chord progression uses similar chords, but they do not obviously relate to any given key center:

[EXAMPLE]

No series of more than two consecutive chords are diatonic to any key, and in particular, there are no dominant/tonic resolutions. This progression is therefore modal.

Note that a chord progression may change keys several times. If each key center is clearly established through tonal means, the whole progression is still considered tonal. For example, the following progression moves through three distinct keys in only eight measures, but it contains a ii-V-I in each key, and is therefore a tonal chord progression:

[EXAMPLE]

A modal chord progression may imply a key center through sheer repetition of a particular chord. For example, the following piece seems to be in F, if only because there are no other chords to argue otherwise:

[EXAMPLE]

To many musicians, this repetition is the definining characteristic of modalism. The progression used previously as an example of modality:

[EXAMPLE]

would be considered something else, such as non-tonal or pan-tonal. However, it does not particularly matter what you call these various types of progressions. The important thing is what you do with them. Once you have identified a progression as modal (or non-tonal, or pan-tonal), what does this mean for improvisation?

In a modal progression, there are rarely two chords in a row that come from the same key. This is true by definition - if this happened often, the music would not be modal, but rather tonal. Because the chords all come from different keys, and they do not resolve in conventional ways, you normally need not even pay much attention to the chords themselves, but you should concentrate instead on the scales the chords imply. This is why the music is called modal - the emphasis is on the scales, not the chords. Some musicians go so far as to say there are no chords in modal music, only scales. When improvising melodic lines over a modal chord progression, you may treat each chord as a scale, and not worry much about the relationship of the notes you choose to the root of the scale. For example, consider the following line:

[EXAMPLE]

It does not rely on thirds and sevenths to outline the harmony, nor is it overly concerned with the concept of "avoid" notes. Rather, a melodic line is constructed over each scale. You should always strive to connect your ideas, however. A modal improvisation should not sound like a series of unrelated statements just because the chords are not related in a conventional way. For example, consider the following two lines played over the same progression:

[EXAMPLE]

Notice how much more naturally the second line flows, because the various phrases within in it relate to each other in a musical way. Whereas the first example might as well have been cut and pasted together from four separate improvisations.

When playing modal music, you can pretty much forget about the substitutions discussed in the previous sections. They are based on the idea of creating different colors while still preserving the original chord function. Since chords in modal music do not function in this sense, these substitutions do not preserve the original intent of the chord at all. For that matter, alterations do not work the same way either. In tonal music, flatting the ninth of a dominant seventh chord creates tensions that is resolved when the chord resolves to the tonic. Altering the dominant seventh chord preserved the intent of reinforcing the resolution:

[EXAMPLE]

In modal music, however, a dominant seventh chord is specified because the mixolydian mode it implies is the desired sound at that particular point in the progression. Flatting the ninth changes the color of the chord for no good reason:

[EXAMPLE]

This is not to say you are never allowed to stray from the notes implied by the scale. On the contrary, you have great freedom. The important thing is to recognize that a chord is chosen because of the sound it represents. You are still free to alter that sound when it suits you. But altering the original chord or performing a substitution based on tonal harmony may not be the most appropriate way to color the sound. If you wish to create tension, you are not limited to the traditional alterations of the fifth and ninth. For example, the following progression calls for a Cmaj7#11 chord:

[EXAMPLE]

The C lydian mode is the expected scale over that chord:

[EXAMPLE]

Any of the notes that are NOT in the C lydian scale might therefore be used to add tension:

[EXAMPLE]

In modal music, you should consider the factors that contribute to the color of a particular chord. For example, G7b9 may be specified because of the dissonance between the G and the Ab. That is probably the most important thing to preserve, and they might well be the most appropriate notes to emphasize melodically, as in the following example:

[EXAMPLE]

Any other chord or scale that contains that essential dissonance might be an appopriate substitute. For example, Abmaj7 might be used to substitute for the G7b9 chord:

[EXAMPLE]

In tonal music, the conventional alterations to the dominant seventh chord are dissonances that are resolved automatically for you when the chord resolves to the tonic:

[EXAMPLE]

In modal music, you must create your own resolutions. A particularly common device is sideslipping, in which the improvisor suerimposes the scale a half step above or below the original:

[EXAMPLE]

Sideslipping is often resolved by returning to the original scale while still on the same chord:

[EXAMPLE]

This is especially appropriate in modal music because it is so common for chords to last for several measures. Sideslipping is a way to create tension and release within those measures.

The longer a chord lasts, the greater the tendency it has to imply a key center. When this happens, you may feel free to exploit this fact. Sideslipping creates tension and release through the use of dissonance. You may instead choose to create interest by creating new chord progressions within the original key. One common device is to alternate the original chord with the V chord in that key. For example, a long series of Dm7 chords can be altered by alternating them with A7 chords:

[EXAMPLE]

This is not completely diatonic, however, as A7 contains C#, whereas the scale implied by Dm7 does not:

[EXAMPLE]

You may instead create motion that is completely diatonic:

[EXAMPLE]

When you are faced with a modal composition that uses only one chord for an entire solo, you will probably be wanting to take advantage of all of these devices, as you can run out of ideas quickly when you are limited to seven notes. Ironically, however, many improvisors deliberately choose pentatonic scales, which contain only five notes, when playing over one-chord vamps. The sound of a pentatonic scale is more ambiguous than that of a conventional scale, as any given pentatonic scale might seem to fit many different chords. The open sound of a pentatonic scale seems to fit the intent of modal music well:

[EXAMPLE]

Copyright 2000 Outside Shore Music
Authored by Marc Sabatella

Modal Improvisation