In order to get the most out of this solo, we first need to take a look at some basic things about the structure of this song.
The Chords and Groove
The "A section" of this song only has three chords, all of which are simple major triads: E major, F major, and G major. These 3 chords sit next to each other on the keyboard, and he uses these simple major chords to create this infectious groove.
Take a moment to think about these three chords. Can we agree E major feels like our home base?
There isn't a key that has only G#'s in it, but there is a scale that almost fits: E Phrygian Dominant.
Whenever I mention the words "Phrygian Dominant," I can almost see eyes glazing over. But hang on, its not as scary as it sounds... I'll hold your hand through it.
What the heck is a Phrygian Dominant scale?
First, consider the key of A minor. We might think about A minor as being the same as C major, but shifted to start on the A instead.
A natural minor, has these notes: A - B - C - D - E - F - G.
In this case, C major is kind of our "home" but we use this natural minor scale to play solos over an Am chord in that key.
But, what happens when we want to play a song that has its "home" in minor? This natural minor scale doesn't work quite as well in that case, so we use a slightly different scale called A harmonic minor.
A harmonic minor scale changes one note: A - B - C - D - E - F - G#. That last note, G#, is the leading tone that helps the A sound more like home base.
And, here's where phrygian dominant comes in. Take this A harmonic minor scale, but shift it to start the scale on the E instead.
The result is a scale with only a G#, and which is rooted in our 'home base' of E.
... but there's still one note wrong.
Let's look at each of Chick's 3 chords, and consider their notes vs. this scale. They all fit the scale except for one...
- E major: E - G# - B
- F major: F - A - C
- G major: G natural - B - D
This song has BOTH a G sharp and a G natural! What!? It has both a major 3rd and a minor 3rd.... WHAT!?
And so this 8-note scale, E Phrygian Dominant with a G natural added, is the basis of La Fiesta. Crazy sauce.