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THEORY 204: Extended Use of the Tritone

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# of guaranteed works reviewed: 5, up until December 10th, 2019.
Special Writing Requirement: Use two of the the three techniques highlighted.
Post LINKS to desired reviewed works from the appropriate forum space in the comments, not the works themselves.

Extended Use of the Tritone
Three things will be covered in this masterclass:
1. Tritone substitutions and their use in jazz
2. An extension of this theory that I personally investigated: difunctional implied tritone shift or (DITS)
3. Tritone key-center relations and common through common tones.

Screen Shot 2019-11-27 at 3.39.14 PM.png

1. Tritone Substitutions:
In the above example, the first section details a deconstruction of what a tritone substitution is and what it can be used for. For any dominant seventh chord in close root position, the tritone within can be extracted. Inverting this tritone and giving it a new root that similarly forms a dominant seventh chord creates a new chord, coincidentally a tritone away from the substituted chord. In the example, the E natural becomes an F-flat in order to work correctly in tonal space. 

In the middle section, a simple chord progression is given: a standard I - IV - V - I, embedded phrase model, or EPM. The final section substitutes the third chord (V) for its tritone, using the same chords from the first section of the example. Notice that in classical terms, this looks very much like a German augmented sixth chord, that resolves to the TONIC instead of the DOMINANT. Despite being related by bII to the tonic, it does not quite have this function either, as an N6 chord has implications in going to another dominant; on the contrary, it has become the dominant. Screen Shot 2019-11-27 at 3.39.23 PM.pngScreen Shot 2019-11-27 at 3.39.28 PM.pngScreen Shot 2019-11-27 at 3.39.36 PM.png

The three examples above show different versions of a relatively identical melody (these are heard in the attached audio file "tritone examples". These examples are more jazz-sounding than the previous example, as this is where the function is primarily used:
I. Standard, normal chord progression with a normal perfect inauthentic cadence (V7-I). 
II. The V chord is substituted for its tritone sub, bII, since in G7, the tritone is B and F. Inverting this, the tritone is F and B (or C-flat), and the proper dominant seventh chord formed with this tritone is D-flat dominant 7th, but the example adds more extensions and actually omits the b7 in favor of the voice leading.
III. Not just the V can be substituted! Passing chord can be created by substituting a normally secondary-related chord. In this case, F7 (tritone E-Bb) is substituted for Gb7 (tritone Bb-Fb), which with the melody creates a brief spicy X7(#9) chord, which is chromatic stepwise in the bass.

2. Difunctional implied tritone shift (DITS):
This is mainly an analytical application of the tritone, but it is related to the tritone substitution, but without the inverting of the tritone in any given chord.

Screen Shot 2019-11-22 at 4.23.28 PM.png

In the example, a reduction from "Shy One", an art song by Rebecca Clarke, the Eb major chord is a bVII relation away from the tonic of F major. If you use the principle of the tritone substitution by adding the seventh to this chord, and instead of inverting it, simply shift it down so that the lowest pitch class becomes the root, an Xm7(b5) tonality will be heard instead. In this case, Gm7(b5) (tritone G-Db) from E-flat7 (tritone G-Db, Db implied), would be the resulting chord, which is bVII related to the following chord, A major. In other words, this is a way to explain the relation between F major and A major, with the given passing chord.

3. Tritone-related formal key centersScreen Shot 2019-11-27 at 3.39.52 PM.png

In the above reduction, the second chord shares a common tone with the first chord (G or F double-sharp), and the second-to-last chord shares a common with the final chord (C#). Using these common tones, it forms an extended common tone modulation, where the beginning of the modulation and the end of it have different common tones. The common tone at the beginning obscures the fact that it sets up a preliminary modulation to the tritone related key of C# minor (could have also been major). The common tone-related chord after that establishes an altered dominant-related chord from G major, though this is not necessary; the main attraction of this method is to use common tones to hide the fact a tritone is the new target of a harmonic progression. In addition, the fact that the final chord in the example is altered gives an overall EPM of all altered chord, where the C#m chord can be interpreted as an altered subdominant function to the altered dominant of V. 



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Hi, this is the first masterclass I participate too. Basically I write a piece using what I learnt in your post and you will review it - correct? Seems like a great idea!

Sorry if it's a dumb question, but what does EPM mean?

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Embedded phrase model (EPM) is the presence of a full Tonic - Subdominant - Dominant - Tonic (i.e. I - IV - V - I, I - ii6 - V - I, i - N6 - V - I) within a larger harmonic structure. This often serves to prolong the tonic despite the changing chords.

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