Tired of using the same old chords in your cues? Modal interchange (also called borrowed chords) is a great technique to add variety and interest into your chord progressions. It’s an idea borrowed from jazz, but I guarantee you’ve heard it in hundreds of pop songs and film scores as well. You’ve probably even used it yourself without realizing it.
Modal interchange combines two rather simple principles. The first is the harmonized major scale. Simply put, that’s a fancy name for taking the notes of the major scale and building triads or sevenths on top of each one using notes diatonic to the scale. In C major, you end up with CMaj7, Dmin7, Emin7, FMaj7, G7, Amin7, and Bmin7b5.
I’m gonna get all classic rock on y’all again. Expanding on Bobby Owsinski’s analysis of Led Zeppelin’s iconic “Stairway To Heaven” from November, I decided to geek out about the theory behind the tune in a little more detail. I realize it’s a rock song and not a film score, but there are some interesting and educational things to learn from the unusual way it’s crafted. In this post I’m also borrowing from and adapting Spy Tunes excellent piece, “How ‘Stairway To Heaven’ Used Modal Scales to Reach the Top.”
Despite “Stairway’s” eight-minute length, it’s relatively simple under the hood. Most of the melody uses just six notes (and their octave equivalents), and there are only five basic chords in the song. Structurally it has four main sections, two of which are related, and one is nothing more than a brief interlude. The apparent intricacy of the tune comes from its use of slash chords, modal interchange, the melodic, harmonic and rhythmic development throughout the song, and of course the remarkable musicianship of the band.
I recently discovered this wonderful set of ebooks by Montreal composer and professor Alan Belkin. He’s got books on musical form, counterpoint, harmony and orchestration, as well as several other articles and essays. I’ve spent the most time with the orchestration book (since I’m currently orchestrating a symphonic piece for a March performance), and it’s excellent. I found it to be simple, straightforward, and full of great advice. Some of it is fairly common-sense and basic, but I never mind being reminded of the fundamentals, especially for something as complex as orchestration. The other books seem similarly well-written and instructional.
Incidentally, Belkin also authored the annotations to the online version of Rimsky-Korsakov’s Principles of Orchestration, available at NorthernSounds.com.