Someone sent me this PM yesterday:
As you know, the most important chords in classical harmony are the tonic (I), subdominant (IV), and dominant (V).
Here they are in the key of C: C major, F major, G major. You can see they make a satisfying-sounding progression.
In basic harmony, one of the only places a dominant seventh chord is found is in V7. By adding F we turn G-B-D into G-B-D-F, a dominant 7th chord.
The disadvantage of V7 is it has a very "obvious" sound. One could say it is almost obnoxiously dominant. Overusing this plain tonality will make your music sound very conservative.
Instead of V7 we can play V7sus4.
A sus4 chord replaces the third of the chord with a fourth. For example the third of a G7 chord is B: we replace it with C.
You can hear the V7sus has a "smoother" feel.
One of the identifying features of Williams' music is that he uses plain V7 very sparingly, preferring V7sus4.
(When he does play V7, he will often play some cool notes on top based on jazz theory; Williams got his start as a jazz pianist and arranger. However that is beyond our scope for now :sweat: )
Moving on: you know that the C major and C minor scales differ by three notes. The C minor scale has Eb, Ab, and Bb. There are a few chords, therefore, that have different qualities when we play them with those notes.
For example you know that IV is F major. But in the C minor scale we would play iv, or F MINOR.
These different chords are called "borrowed chords" because we can "borrow" them from C minor and play them, even when our piece is in C major. We do this because the borrowed chords are like adding color or spice to our music.
Williams loves borrowed chords (he is not alone among composers in this!) but he has a particular affection for bVI.
If I play bVI then I, you can hear how strong that chord progression is. Especially if I put G in the bass below bVI (which technically turns it into a major seventh).
If you compare bVI-I to the classical V7-I, you can hear that the first chord progression has a more colorful, unpredictable, dynamic and modern sound.
Williams often uses bVI as though it were a dominant chord.
Finally I have to explain Lydian II. Now you may know that the Lydian mode of C, is like the C major scale, with ONE DIFFERENCE, it has an F# instead of an F.
When you play a D major chord over the note C, you get a dreamy sort of sound. This is Lydian II. There is a more technical name for this chord (V7/V) but when Williams uses it, his intention is most often to add a Lydian sound to the music.
Lydian II is yet another of Williams' favorite chords.
Now to prove that I'm not just making stuff up let's look at some tunes from Williams' music.
The first tune we can look at is the theme from E.T. The Extra-Terrestrial.
Some things to note about this: listen how the Lydian II gives a magical sound. Also notice how Williams uses bVI as the "climax" of his chord progression, not V.
Now here is the Force Theme from the Star Wars movies. Notice the V7sus4. And also notice the use of two borrowed chords bIII and bVI.
Now finally here is a tune from Harry Potter. It uses only I, IV, V7sus, and bVI! (Well and one GbM chord).