Rhythm changes y el ciclo de séptimas dominantes

Rhythm Changes

We're now going to turn our attention to rhythm changes. This is short for the chord changes of "I Got Rhythm", a Gershwin standard that has been the template for a whole bunch of tunes mainly written by jazz musicians over the same chords, like "Take the A Train".

Structure

• Format: AABA sequence, 32 bars long
• Key: Usually played in B flat
• Tempo: Often played quite fast

This is quite a challenging tune or chord sequence to play over. I've simplified it somewhat and just made the A sections with one chord, but you'll hear the bass line actually implies a lot of other chords. For the time being, we're not going to be bothering with them.

Key Features

One of the key things about rhythm changes is that the bridge (the B section) features a little chunk of the dominant seventh cycle. Now, we're going to be exploring some bass lines for that, two bars on each chord.

D7 Bass Line

Here's the D7 bass line:

• It goes up to the sixth or rather triad
• Then the sixth
• Followed by a scale down from the root (or a run down)

This takes us straight to G, the next chord. And for G, we're going to do a scale pattern:

1. Scale down
2. Repeat pattern: Root, 3, 5, 6 on C
3. Scale down
4. Scale pattern on F

Next, it's going to go back to the bass line for the A sections in the left hand.

The Bridge

In the bridge, the dominant seventh cycle, you could play tritones like we did in the previous tune. Remember, they're going to go down in semitones.

This is a pretty easy and hip way to play the left-hand chords if you're improvising, exactly like we did in "Dominant Seventh Workout."

Practice Approach

However, the first time around, we're going to practice just playing the bass line and chords. This way, we can integrate that bass line into practice. Then, we'll return to the last eight bars.

This is what you could play while someone else maybe takes an improvised solo over that bridge.

Improvisation Insight

One of the things about rhythm changes is that, while there may be a melody written for the A sections, the bridge (or the middle section around the dominant seventh cycle) is often a little mini solo. Usually, the band leader will take that.

We're going to look at the theme by Miles Davis, which was used as a signature tune for many years with one of his great quintets. The bridge could be taken by various people.

But of course, when we actually go back and take a solo around the whole form, it's going to be 32 bars every time, and the whole thing will be improvised.