Diatonic harmony is based on 3rds, and that’s how most of us define the chords we play when we’re reading or analyzing music. When we begin the study of music theory, usually one of the first things we look at is how different varieties of triads are created by playing the root, third and fifth up a major or minor scale:

Ex. 02

Listen to audio of Ex.02

Of course, when the notes of the scale change, so do the qualities of the triads:

Ex. 03

Listen to audio of Ex.03

Now if we add one more third to each chord, we have the 7th chord:

Ex. 04

Listen to audio of Ex.04

As a point of interest, we really get a lot of extra harmonic color when we flesh out the 7th chords of the Harmonic Minor scale:

Ex. 05

Listen to audio of Ex.05

In fact, I really believe the whole reason the Harmonic and Melodic Minor scales came about was the desire for more harmonic strength and melodic variety while still adhering to the confines of post-renaissance-era diatonic harmony.

Now; nobody strictly sticks to the notes defined by the key signature they’re in with any regularity. Scales, key signatures and the chords they naturally create should not be thought of so much as a formula for writing than as a guideline. The fact is that composers have always altered scale notes or chords in their work to create the colors and strength of purpose that they need to make a composition interesting.

Let’s examine this short example of a popular Lennon McCartney song:

Ex. 06

Listen to audio of Ex.06

Making the decision to use a C major chord in the key of E major gives the composition a strength and brightness that you would never get if you used C# minor- the nearest available chord that adheres strictly to the key of E major. Changing that chord alters several scale notes and opens up the opportunity for melodic invention simply not available by sticking to strict key signature notes and chords. Which is why everybody deviates from the formula- they would go crazy if they didn’t. (Note that the C# minor chord was used earlier on as part of a descending bass-line motif). If you always followed the guidelines of the key signature at hand, music would be phenomenally dull and would never change keys, but at least you wouldn’t have to put in those pesky accidentals.

Which brings us to jazz- early jazz. Harmony and melody really got a kick in the pants with the onset of jazz in the early 20th century. Now musicians and composers were liberally substituting Dominant 7th chords for major (and minor!) chords, adding major 6ths to minor chords, and plopping diminished and diminished 7th chords on passing note roots like the augmented 4th – opening up vast amounts of harmonic color and melodic variety that was not accessible by utilizing the standards and practices of classical European or American folk song writing.

Augmented chords were also liberally employed- the augmented 5th of a V chord, for example, often being the leading tone to the third of the I chord:

Ex. 07

Listen to audio of Ex.07

Harmonically speaking, when you stick to the notes of a C major scale, this is what you get with a (common) I, VI, II, V chord progression:

Ex. 08

Listen to audio of Ex.08

Ok for doo-wop, but here’s what happens with some chordal alterations:

Ex. 09

Listen to audio of Ex.09

There is definitely more tang to this progression and you have a bunch of altered scale notes to get creative with, and which practically demand a bit more chromaticism (mainly as passing tones):

Ex. 10

Listen to audio of Ex.10

The diminished 7th and half-diminished chords began to appear largely to address, I think, the added chromaticism and passing tones in the melody. In this example the diminished 5th of the D half-diminished chord becomes the leading tone to the root of the V chord (G7), which is a common tone with the 5th of the I chord (C6):

Ex. 11

Listen to audio of Ex.11

Their presence adds additional opportunities for melodic excursions, often by using diminished scales in the melody:

Ex. 12

Listen to audio of Ex.12

Why have I spent so much time thinking about this early jazz stuff, especially since I was raised on the Beatles, Frank Zappa and Gentle Giant? Because I had to. A year or so ago I was asked to compose the music for "The Princess And The Frog", a video game released concurrently with the animated movie of the same name, and I had to steep myself in the New Orleans tradition and compose music that was largely in the style of Dixieland-era jazz. I also got to write some zydeco music and other styles appropriate to the theme of both the game and the movie, but more contemporary jazz, anything approaching later-era big band or bebop styles were mostly off limits. The occasional 9th, or 11th chord would be ok, but mainly we are talking about early 20th century jazz, with its roots in American popular music - Stephen Foster- barbershop quartets. Major, minor, diminished, augmented triads and diminished 7th, half-diminished 7th, and augmented 7th chords were to be the staples of this Dixieland diet.

And counterpoint! Because improvisation was really looming to the forefront of the jazz performance, it was inevitable that counterpoint would become a weightier component in the fabric and performance of this music. Many of the arrangements were often a heavily collaborative effort between the performing musicians and the composer. This is, in fact, where I think the term “head arrangement” must have found its origin. Musicians would often “blow” solos over the verse or chorus of the song, sometimes all of them at once. That’s some heavy polyphony there!

This is what I had in mind when I wrote the "Diner" piece for "The Princess And The Frog" game. Since I didn’t have a lot of time to rehearse with musicians, and some of them had limited experience improvising to early jazz styles, I decided to write a piece that was basically a Dixieland counterpoint piece. As if the musicians were improvising over a chord progression, but (almost) every note was accounted for in the score.

Below is an excerpt from that piece (the tuba is mainly playing the bass part and the banjo and piano are working off the chord symbols, creating their own “head arrangement” for the piece):

Click to view / download:

• Diner_Edit_Score_pg1.pdf
• Diner_Edit_Score_pg2.pdf

Listen to audio of "Diner (Edit)" by Steve Kirk

I’ve only begun to explore how the use of the “blue” note (the augmented 4th), the blues scale, and many other scalic possibilities are so warmly invited by these chordal alterations. It could take up at least one or two more articles! Maybe a better idea would be to try writing out a couple of chord progressions yourself- perhaps following the triad or 7th chord formula of a major or minor scale and just start changing the quality of the chords- from minor to dominant 7th, from major to minor, from using the root of the major 6th interval to create your chord to using the root of the minor sixth interval (like example 6) and see what happens.

Composer, guitarist and arranger Steve Kirk's music has been featured in film, video games and TV. This includes music for the Disney game version of "The Princess And The Frog", Microsoft Games "Voodoo Vince" , the FarmVille Theme for Zynga Games, and to be released in Spring 2011, Cantina music composed for the Star Wars MMOL game The Other Republic.

Steve teaches guitar, music theory and composition privately in Oakland, California, as well as Blue Bear School Of Music and Community Music Center- both located in San Francisco, California. He is also the guitarist for Club Foot Orchestra and Orchestra Nostalgico.