Please watch this wonderfully-made video on modal interchange – another name for mode mixture – created by Myles Yang for his Native Construct YouTube channel. In it, he demonstrates possible mode mixture beyond parallel major and minor modes. If you are not familiar with modes beyond major and minor (Ionian and Aeolian), please review Unit 2. You can also quiz yourself on modes at musictheoryfundamentals.com.
This video does a great job of explaining the concept of mode mixture, but as he mentioned near the end of the video, he is only “scratching the surface”. Having watched the video, you probably feel that you understand the extended concept of mode mixture, but if you were asked to compose a progression and melody using this advanced language of mode mixture, do you feel that you would be able to implement it? Where would you start? Why did he choose these particular chords? How did he know where they would sound convincing? In short, this video explains the question of “what is this?”, but it does not approach the questions of “why this works?” or “how can I use this?”.
To begin exploring this, use the score below to try voicing one of the progressions taken from the video. Take risks, and break the “rules” as you try this. You must use the chord progression below, but you may alter the bass and soprano lines if you would like. You may also add as many or as few of the pitches as you need. Are you able to make this progression sound as pleasing as it does in the video? If not, what are the factors making this difficult? From a technical viewpoint, is it lack of knowledge or is it the medium (MIDI keyboard)? From a musical viewpoint, what aspects make the biggest improvement when you alter them?
Even though this is an entirely new style of progression, you can focus on the fundamentals of voice-leading to guide you. For example:
If you do these things, it is fairly easy to write smooth soprano and bass lines and then work your way backward through the progression to create something such as this:
As you have hopefully come to realize, all tonal harmony–even the chromatic alterations–rely on voice-leading to create a sense of natural progression, and each harmony can be viewed through the lens of how it functions. From this, we derive primary harmonic functions such as tonic, dominant, and pre-dominant as well as embellishing functions such as passing, pedal, and cadential. Even the exceptions to these can be viewed as functional substitutions (e.g. deceptive progressions).
At its core, mode mixture borrows altered tones from parallel modes, thus altering chord qualities, but retains standard chord function. If a diatonic chord would have a pre-dominant function, altering an individual tone by a half-step will not alter the function. It creates color and often strengthens the voice-leading by changing whole-step resolutions into half-step resolutions. Moreover, if a chord functions as an embellishing chord such as a passing or pedal chord, then it will retain that function even if one or two pitches are borrowed from a parallel mode.
Even seemingly inexplicable choices can be explained, such as the iiø7 from the chord progression above, if you look at the voice-leading and compare it to standard diatonic function.
With this in mind, let’s return one more time to the reduction of the excerpt from Mahler’s Symphony No. 2. Does this provide further context as to why we can consider the bII as a dominant function?
In this case, the bII is acting as a functional substitution for a dominant function (or possibly a plagal cadential function). It shares many common tones with a viio7 chord, and these tendency tones follow the voice-leading resolutions that you would expect of a viio7. When it is used to resolve to a I chord, the voice-leading issues are difficult to overcome, so you must be thoughtful in your approach and resolution.
Please note: While the Neapolitan is a commonly used chord, it is far more common to use it as a predominant function rather than as a functional substitution for dominant. Remember that if you ignore the standard tonic/dominant relationship too often, the listener will begin to lose the sense of diatonic progression. This can be good or bad depending on your desired outcome.
As always, if you study a chord’s voice-leading, you can use this to deduce its function.
Analyze the following two chord progressions. What factors help you decide how to label each chord? Which tones are chromatic passing tones, and which create new harmonies?
Chromatic passing tones often create harmonies that could be considered borrowed chords, but the determining factor should always be its function. If the resulting borrowed chord does not sound as a defined function (e.g. tonic, dominant, pedal, etc.), then the pitch should be classified as a passing tone. If the chord operates as a functional substitution (tonic, dominant, pre-dominant), then it is better to label it as a borrowed chord. If each member of the chord functions solely for smooth voice-leading purposes, then it should be labeled as a borrowed chord with an alternate function such as a passing or pedal chord.
In the example above, most will hear the first iteration as a I-IV-iv-I progression. The chromatic tone of the iv chord on beat 3 is present for the entirety of the beat and fits the harmonic rhythm of one chord per quarter note. Considering beats 2 and 3 as one chord would allow you to label the A-flat as a chromatic passing tone, but the A-flat is present long enough to make this difficult to hear as such. Conversely, the A-flat in the second measure is only present for an eighth note and occurs in a weak position. In this case, the A-flat is a clear chromatic passing tone and would not be labeled as a borrowed iv chord.