In this article, I'll explain the difference between diatonic chords and chromatic chords, and explore some cool, ear-bending harmonic choices that we can use in our own music. You may have stumbled across interesting sounding chord combinations already and been unaware of exactly why they worked well together, and some music theory can help better understand and use these chord combinations. If you haven't already then check out my previous article on chord progressions.
What are chromatic chords anyway? There are 12 possible note choices when composing, seven of those belong to the major scale (they are diatonic) and the 5 notes not in the scale are the chromatic, out-of-key notes. Here they are in the key of C:
Diatonic chords are built from notes of the major scale, so with these seven notes, we can build seven chords (C major, D minor, E minor, etc...). Most pop music is built from this approach to diatonic harmony, and that works fine. However, we can spice our chords up a little by borrowing some of the chromatic notes to make chromatic chords. For example, if we're composing in the key of C major, we can use an E major chord built from the notes E, G# and B. The G# is from outside the key of C, and so is chromatic.
Popular Chromatic Chords
Here are a couple of tried-and-tested chromatic chords that appear in pop music a lot.
Turn the fourth chord of the major scale, which is usually major, into a minor chord, and you'll get very a melancholy effect. In the key of C major, this would be an F minor chord. You can hear it in Blackbird by The Beatles and Creep by Radiohead. Bonus points if you turn it into a minor 6 chord.
The seventh chord of a major scale ends up being a diminished chord, which isn't that useful for writing. Borrow the flat seventh from outside of the scale and you get a bVII chord great for rock and roll.
Major III Chord
Turn the third chord of the scale from a minor to a major chord and we get a Major III chord. This is sometimes used to resolve to the minor chord a fifth down from it, creating a cadence. For example in the key of C, an E major chord resolving to the A minor chord. This also makes an appearance in Creep by Radiohead (G | B | C | Cm)
Let's check out some real-life examples from song's I've previously covered in my synth tutorials!
Sober by Childish Gambino has a Fmaj7 | Dm7 | Ebmaj7 chord progression. The first two chords sit firmly within the key of F, however, the Ebmaj7 is a bVII chord in the key of F! The major seventh voicings really make it an ear-catching groove.
Paranoid by Kanye West has the most obvious use of major/minor swapping, as it swaps the major root chord with a minor chord to create a tonally ambiguous effect, neither major nor minor. The song is in F# major and switches from F# major 9 to F# minor 9, before returning back to chords within the key of F# major.
Nangs by Tame Impala, which I covered in my first Tame Impala article, features some ear-bending chord movements. In the key of C major, there is an Eb - Abmaj7 turnaround to lead into the repeat. Both chords are borrowed from the parallel key of C minor, so it feels almost like a key change.
Another One by Mac DeMarco has a lot of unusual chromatic moves, for example, the verse is E | D#m | D | D#m B, creating chromatic bass movement. The key switches between E and B, and the D chord works as it's the bVII chord in the key of E, which the verse starts in.
The Whaler by Thrice is fantastic song, for a start it's in 5/4 time signature, it also has some really interesting chord choices. Within the key of Eb major (C minor is the relative minor), there are two chromatic chords. The first is the Dbmaj9 in the verses, which is a bVII of Eb major. Second is the G major chord in the pre-chorus, which is the major III chord of Eb.
Thanks for reading! Confused? Got any questions? Feel free to ask away in the comments section!