Improvising Over Chord Changes
When beginning to improvise on the guitar, students almost invariably learn what is called a “key-centered” approach. This entails determining the key of a song or chord progression, then using its corresponding scale as a pallete with which to improvise. This is a useful and entirely valid approach that guitarists at all levels use throughout their musical careers depending on the harmonic structure or style of the song over which they are improvising.
An equally valid and more challenging approach known as “playing over the changes” derives its improvisational palette from the “chord of the moment.” Each chord in a progression is made up of a set of pitches and adroit improvisers can “target” the pitches specfic to each chord to guide their phrases. This approach yields a solo in which the improvised melody sounds more interwoven with harmony than a key-centered approach. Improvisers use both approaches, often within the same solo.
In this article, we will discuss the four simplest and most common methods of playing over the changes. Each creates its own unique sound. Some create smooth lines, others lines that leap. Some create lines that perfectly fit each chord, others inject more color tones. Competent improvisers learn to use each method to imbue their solos with whatever feeling they wish, making choices intuitively. You can play each example below to get a feel for how each sounds.
Improvisers can draw from the parent triad of any chord as it passes during a progression. In the following example, the melody shifts from an A minor triad to a D major triad and finally to a G major triad over a IIm-V7-Imaj7 progression. As all the pitches within a triad are at least a third apart, improvising with triads produces an “angular” melody, composed of a series of leaps. This approach also creates the most consonant lines, as every pitch perfectly fits the underlying triad. Notice how the melody shifts at the bar line to the nearest note in the next triad while maintaining the same direction, as opposed to leaping to the new triad’s lowest note. This is an integral approach in all methods when improvising over chord changes.
2. 7th arpeggios (and extended arpeggios)
Some chords have added 7th notes or extensions (the 9th, 11th or 13th degrees of a chord) that can be exploited for improvisation. But even simple diatonic triads have 7ths and extensions that can be played over them. In this example, the melody progresses from an A minor 7 arpeggio to a D7 arpeggio before finally arriving at a G major 7 triad. As 7th arpeggios have one more note than triads, the melodies they create are a little less angular and a little more smooth.
3. Pentatonic Scales
A convenient fact about pentatonic scales is that since they include a triad, they fit over a great deal of chords. As they have five notes (more than triads and 7ths) and more tensions (non-chord tones) they create even smoother lines with more color. They also have the added benefit of allowing the improviser to utilize their blues licks over any chord progression. In the following example, we shift from an A minor pentatonic scale to a D major pentatonic scale before ending on a G major pentatonic scale.
Each diatonic chord has an associated scale, known as a “mode,” which can be used for improvisation. In the example below, we shift from the A dorian mode to D mixolydian mode to the G Ionian mode. Incisive students may notice that these are all notes from the G major scale, so the improviser is really just playing up and down a G major scale; this is true. However, as chord progressions become more complicated, non-diatonic chords will require modes from outside the major scale. Additionally, modes that are not diatonic but still fit a chord’s tones can be “superimposed” over the chord. This opens up a large improvisational palette.
Learning to improvise over changes take time. Often the sticking point is not the shapes themselves, but being able to make the shifts in time with the chord progression. This takes a good ear, musical awareness and the ability to think ahead. We will develop this technique gradually, learning each shape by itself and incorporating it over simple progressions. These progressions will get incrementally more complex. Eventually, you will be able to mix these approaches over any chord progression to intuitively create solos with a great deal of complexity.