Episode 2 : The tritone substitution.


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This episode shows how it's possible replace a dominant chord with another dominant chord a flat 5th above and shows how you can apply this to the song Georgia On My Mind.

For more scores and other supplementary material to accompany this and the other GuitarBytes episodes visit www.guitarbytes.co.uk

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Episode 2 : The tritone substitution.

  1. 1. The tritone substitution Podcast #2 - Additional notes © Copyright Darren Dutson Bromley 2012
  2. 2. The Tritone Substitution.Last week we saw it was possible to replace a dominant chord with a minor 7th chordwhose root lies a perfect 5th above. For example the note a perfect 5th above G is D, so itis possible to substitute Dm7 for G7. This week we’ll take a look at another very commonsubstitution for a dominant chord often referred to as a tritone substitution.The term tritone is exactly what it says it is, three tones. A tone on the guitar is theequivalent to two frets, a semitone which is the smallest recognised interval in westernmusic is one fret. Starting on the note G, a tone above would give A, a tone above A is Band a tone above B is C#. This is a tritone.Often the note a tritone above is referred to by its enharmonic equivalent of b5th ratherthan #4th.It is possible to replace a dominant chord with another dominant chord whose root lies aflattened 5th above. We could replace a G7 chord with Db7 in a sequence and surprisinglyit doesn’t sound out of place or unusual.For example.Could be played asThere are a number of reasons why this works so well. The active ingredients in a G7chord are the 3rd and the 7th. All chords are built from scale tones, a dominant 7th can bebuilt using the 1st (root) 3rd, 5th and b7th tones of a major scale.
  3. 3. The G major scale consists of the notesG A B C D E F# GThe root note is G, the third note is B, the fifth note is D and the flattened seventh is F.These are the notes from which a G7 chord is constructedG B D FLooking at the function of each of these notes. The role of the root note is to name thechord, the 5th adds a bit of padding (unless it is altered), the 3rd is very important as itdictates the tonality of the chord, whether the chord is major or minor, and the 7th is alsovery important as it prescribes function, whether the chord needs to resolve onto anotherchord or not.All the active information of a dominant 7th is contained within the 3rd and the 7th.Looking at the notes of a Db7 chord, the substitute chord for G7, we have these notesThe Db major scale: Db Eb F Gb Ab Bb C DbDb7 chord:! Db F Ab Cb! ! ! root 3rd 5th b7thThe F and the B (Cb), the two active ingredients of a G7 chord are also present giving theDb7 chord the same qualities as G7.An easier way to find a note a tritone above is one note higher on the next string. Thisworks across all the strings apart from the third string due to the second string being tuneddifferently, here it is two frets higher.
  4. 4. The chords to the classic piece Georgia On My Mind by Hoagy Carmichael look like this.Looking at the G#7 chord it is possible to apply the substitution discussed last week. Thenote a perfect 5th above G# is D#, we could therefore substitute D#m7 for G#7 or use it tocreate more harmonic movement in a bar by including both chords.The note a tritone above G# is D allowing us to substitute the chord D7 for G#7.We could also include the two substitute chords in the bar.It is also possible to include the original chord. This creates much more harmonicmovement in the bar and the chords resolve beautifully on to C#m7 by movingchromatically towards it.Try using these substitutions in different chord progressions; they are an excellent way ofcreating different colours and variations in a sequence.See you next time