Of all of the possible musical intervals, the tritone could easily be the most misunderstood. Banned for most of the last millenium in the churches of Europe due to it's dissonance, the tritone has gradually come to prominence in American blues and jazz, where it has found it's way into many cool lines and is oftentimes commonly referred to as one of the blue notes. Example 1.
| impending doom of the minor 3rd | tritone doom |
Remember this lick? Sound familiar? Maybe slow it down a bit. Does it get anymore cliche? Pure tritone. Can you sing the line?
Maybe the impending "doom" of this last idea is what made the church think twice about using this pitch in their music. Lest we forget that only from the church music that was preserved, can we get a glimpse of what some of the music sounded like from the latter 1st and early 2nd centuries of European civilization. Speaking of Europe, the tritone interval is one used for their emergency signals. Example 2.
So, have a sense of the sound and it's theoretical label? Cool. Is there an easy way to organically derive this pitch from within equal temper? The pitch, formally known as the tritone, is created by splitting the octave perfectly in half. Example 3.
| octave up | tritone | tritone | octave down |
When measured from the root, the tritone interval is usually labeled and named one of three ways. Here are the first two tritone labels, both are "simple" intervals. Example 3a.
| augmented 4th ( # 4th ) | diminished 5th ( b 5 ) |
Expanding either of these intervals by one octave creates what is commonly termed the sharp eleven ( # 11 ), which is usually associated with the harmony. Example 3b.
| expand the # 4/b5 by one octave | C major 9 | C major 9 #11 |
Dig that tonic # 11 chord huh? Just one of the ways to use it's dissonance to work the magic. Is the tritone dissonance softened by the compound interval from the root to #11? Maybe a bit. And does the 9th of the chord D help to soften the color? Yep. Why? Is this softened sound in a sense polytonal. Yep. Hip to the idea of polytonality?
So, we simply split the octave perfectly in half to locate the tritone, then measure the musical distance from the root to find it's common numerical labels or intervals.
So, where do we use this most dissonant of intervals? Well, let's insert two varieties of the tritone color into each of the ancient pentatonic colors and see what happens. Example 4.
| minor pentatonic | + one pitch tritone ( F# ) | major pentatonic | + two pitch tritone ( B / F ) |
Sound familiar? Adding one pitch, the intervalic distance of a tritone from the root, into the minor pentatonic color creates the blues scale. Inserting a two pitch tritone interval into the major pentatonic color creates the major / natural minor scale. Cool n'est pas? Is this adding the tritone an important evolutionary step in music history? Could very well be.
In chords, we use the tritone interval to create the all important dominant 7th chord, the ultimate harmonic "traffic cop" for directing the flow of harmony in many styles of American music. Example 5.
| G major triad | adding the 7th / F | revoiced G 7 | tritone B / F |
By adding the 7th chord degree above the root G, we create the tritone interval between the 3rd of the chord and the 7th, B / F. Is a chord's quality determined by it's 3rd and 7th degrees? This essential dominant chord tension oftentimes resolves in the following manner. Example 2b.
| G 7 | C minor | G 7 | C major |
Nice voice leading huh? Simply moving each voice the smallest interval possible to it's resolution as determined by the next chord in the progression. Is the Five to One chordal motion the most common of the cadential motions throughout the styles of American music? Pretty much. Is the dominant chord like the "traffic cop" in directing the tension and release of harmonic motions?
We can add a second tritone interval to the dominant 7th chord creating the not quite so common dominant 7th / flat 9 color, V 7b9, an potentially essential color for the advancing jazz artist. Example 2c.
G 7 ( tritone interval between the pitches B and F ) |
G 7 b9 ( tritone interval between the pitches D and Ab ) |
Dig the V 7 b9 chord, one home of the fully diminished 7th chord, which just bristles with tritone intervals and leading tones... To whence they go hither ...?
So why is the tritone potentially important to the creative American musician? Well, initially for a couple of reasons. First in that the tritone is an essential blue note within the blues scale, perhaps the true "core group of pitches" of all of the styles of popular American music, both past and present. Second, that the tritone color creates the essential tension within the dominant 7th chord, an important component in the creation of artistic tension and it's resolutions within the major / minor tonalities as created by the equal tempered system. Hungry for more ideas about the tritone? Ever had a tritone sub? Hip to the diminished scale?
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"You're only a half step away from your nearest tritone dissonance." Dave Grippo
