What do we need to know in order to improvise over a set of chord changes? What is the difference between jazz soloing and rock/pop soloing? What about blues? How do I handle that? These are the questions that are most often asked by music students when first starting to improvise. It can be intimidating for musicians who are used to playing only what they see on the page. Improvising for most people requires knowledge of music theory that is often lacking in the non-improvising musician because realistically it is not a necessary requirement for reproducing notes from the page. Sure, most trained players understand key signatures, scales and basic harmony but mainly in the sense that it benefits their playing through technical development and sight reading. It is another thing entirely to actually create music spontaneously with these ingredients. I believe improvising is the best way to really understand how music works through the practical application of all of its elements.
Let’s examine the first question; what do we need to know to play over a set of chord changes? The first and most important is to know what key you are in so that you can choose the correct scale for improvising. This requires knowing the diatonic chords that are generated in most cases from major and minor scales so that when we look at a progression of chords we can determine the key or scale they are derived from. A quick review of the diatonic triads in C major:
C (I) Dm (ii) Em (iii) F (IV) G (V) Am (vi) Bdim (vii)
So in most simple tunes you will find a set of chords like C G Am F and you would then say: OK, I know these chords are all diatonic to the C major scale so I can use the C major scale for my improvisation since all notes in the chords are within the C scale. This is a basic but important point; the scale that you choose to solo with must contain the notes that make up the chords. The notes that will sound best to your ear as you are soloing are the ones that happen to be contained in the chord that is sounding at that moment. Blues is a notable exception to this rule where it is desirable to play notes that are not in the chord, the so called “blue notes”, which give blues its characteristic sound. Usually it is easiest to start improvising using a method where we group as many chords as possible within a key area and use the one scale that generates these chords.
This leads to the second question; what is the difference between jazz soloing and pop/rock? The main difference is that jazz soloing usually requires changing key numerous times through the course of the tune. We may start with a chord progression in C major but then we suddenly find that the chords no longer fit in C. This usually signals a change of key and will require that we must now use a new scale for our solo. Also jazz harmony is considerably more extended or embellished than the harmony of most pop tunes. This actually works to our advantage since the more notes there are in a chord the less chance there is of playing a bad one. This is not to say that pop/rock is elementary or inferior in any way to jazz; it’s just a different approach. I find that it is sometimes more difficult to come up with an interesting solo over simple chord changes (chords with fewer notes) because the choice of notes is limited. I know many great jazz players that can’t adapt to the style.
Now let’s look at a typical jazz tune and make some decisions about how we should solo over the chord changes. It is always a good idea to start with a tune that doesn’t change key, or if it does, the key it moves into is the relative minor. Since the relative minor uses basically the same pitch set as the major with the exception of the raised seventh (harmonic minor) we will start with a tune that has these key relationships; major/relative minor. This is a very common key relationship and is used quite often in many tunes. We will use the jazz standard “Autumn Leaves” to start.
The chord changes are as follows. I will use C major to keep it as simple as possible.
Dm7 | G7 | CMaj7 | FMaj7 | Bm7b5 | E7 | Am7 | Am7 |
Dm7 | G7 | CMaj7 | FMaj7 | Bm7b5 | E7 | Am7 | Am7 |
Bm7b5 | E7 | Am7 | Am7 | Dm7 | G7 | CMaj7 | CMaj7 |
Bm7b5 | E7 | Am7 D7 | Gm7 C7 | FMaj7 | Bm7b5 E7 | Am7 | Am7 ||
The key signature would indicate C major/A minor or no sharps or flats so we could assume that it is in C Major/A minor and indeed it is. To confirm this we need to analyze the chord progression using the traditional numbering system in which roman numerals (large and small) designate the scale degree that is the root of each chord; upper case for major chords and lower case for minor. A quick review of the diatonic seventh chords in C major and A minor:
CMaj7 (I) Dm7 (ii) Em7 (iii) FMaj7 (IV) G7 (V) Am7 (vi) Bm7b5 (vii)
Am7 (i) Bm7b5 (ii) CMaj7 (III) Dm7 (iv) E7 (V-harmonic minor) FMaj7 (VI) G#dim7 (#vii-harmonic minor)
The letters indicate key areas. The analysis would be as follows:
C: ii | V | I | IV |Am: ii | V | i | i |
C: ii | V | I | IV | Am: ii | V | i | i |
Am: ii | V | i | i | C: ii | V | I | I |
Am: ii | V | F: iii V/ii | ii V | (I) Am: VI | ii V | i | i ||
You can see by the analysis that nearly everything fits nicely into C major and A minor with the exception of that little excursion into F major toward the end. As a reminder; the E7 is the V chord in A minor because we usually use harmonic minor (#7) when spelling the V chord.
You will notice that this tune is based harmonically on a pattern of root movements that descend by fifth. As we noted in earlier discussions this is very common in many jazz compositions and is the basis of the famous ii-V-I chord sequence we all know and love. Make note of the difference between a ii-V-I progression in a major key and a ii-V-i progression in minor. Let’s compare the two:
C Major ii-V-I = Dm7 G7 CMaj7
A minor ii-V-i = Bm7b5 E7 Am7
What is most important to note is the quality of the chords. In major keys the (ii) chord is a minor seventh chord and in minor keys the (ii) chord is a minor seven b5 chord. The (V) chord is the same in both major and minor (because we use the harmonic minor scale for the dominant in minor keys). The tonic chord (I) of course is major in major keys and minor in minor keys. The difference in the quality of the (ii) chord is an important signaling device. It usually tells us we are about to move into a major or minor key. For example if we see Bm7b5 it usually tells us we are about to move into A minor. This minor seven b5 chord is most commonly used in jazz as a (ii) chord in a minor key. It is usually followed by the (V) chord and then the tonic (i) chord. If we see Bm7 we are more than likely moving into A Major as this would be the (ii) chord in A major. This helps us anticipate key changes when soloing through a tune.
Finally let’s take a look at the chord progression in the tune “Blue Bossa”. I like to use this tune as a perfect example of the ii-V-I progression in major and minor keys. This tune is a bit more complex since it involves two keys and consequently we will need two scales for soloing. The chords and analysis is as follows:
Cm7 | Cm7 | Fm7 | Fm7 | Dm7b5 | G7 | Cm7 | Cm7 |
Cm: i iv ii V i
Ebm7 | Ab7 | DbMaj7 | DbMaj7 |
Db: ii V I
Dm7b5 | G7 | Cm7 | Dm7b5 G7 ||
Cm: ii V i ii V
When analyzing a chord progression I find that in most cases it is best to find the dominant seventh chord and assume it is the V chord of the key you are in at the moment. Then work around the V chord to determine how the other chords fit into the key. Remember that this dominant seventh type chord (major triad/minor seventh) occurs most commonly on scale degree V so we can be pretty sure that it is the V chord of the key we are in. Group as many chords as possible into the key, numbering them as you go along until you find a chord that no longer fits. Once this non-fitting chord is found, move ahead until you come across the next dominant seventh chord. This is usually the V chord in the new key. By working backwards you can then figure out how the preceding chords fit into the new key. In “Blue Bossa” we have two dominant seventh chords, G7 and Ab7. These are the V chords in the respective keys of C minor and Db major. We can work around these to determine how the other chords fit in as I have shown above. Now that the key areas have been determined we can improvise over these chords with the corresponding scales. With some experience you will be able to do this on the fly and negotiate complex tunes with multiple key changes.
Of course most tunes are much more complex than my examples and contain harmonies such as secondary dominants, tritone substitutions and borrowed chords (modal mixture) as well as multiple changes of key. Since tunes like these contain so many harmonies that are altered or contain notes outside of our diatonic major and minor scales, it is usually best to improvise over these tunes by treating each chord as an entity unto itself. In other words it would not be possible to group these highly altered chords into any one scale, so we must treat them as separate things where we have a particular scale for each chord type. Better yet is a system of improvisation known as “target tone” improvisation that emphasizes the targeting of chord tones as a way of building lines that flow smoothly through the changes of harmony. This requires knowing chord structure well and arpeggio patterns on your instrument. This will be our next topic for discussion. Again please stay tuned.