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Jazz Guitar Lessons

Understanding Harmony on the Guitar



In thisJGT lesson,jazz guitarist Leon Rodriguez explains harmony onthe guitar in this music theory lesson specifically for guitarists.

The interval pattern of a whole step, whole step, half step together makes up a tetrachord. Two tetrachords connected by a whole step makes aDiatonic Major Scale. Let’s build the harmony of the C major scale which has akey signatureof noaccidentals(sharps and flats) i.e. the black keys of a keyboard. The key of C major is all-naturalnotes as is our fretboard diagram, i.e. the white keys of the piano.

In the following 2 bars, we layout a major scale on the 2ndstring recognizing a C tetrachord in the first measure and a G tetrachord in the second measure. Together, they make up the first and second halves of a C Major scale; a key to understanding the mechanics of theCycle of 4ths and 5thsyet to come.

Play the next two bars, thinking, saying or singing thesolfeggiosyllables placed above each note. We construct harmony by stackingevery other notein the scale. This will have a Consonant sound.

Our selections have paired ‘Do’ theCand ‘mi’ theEskipping over ‘Re’ theD. This is an interval of a 3rd. There are two types of 3rds, a major third, (4semitonesor frets), anda minor 3rd, (3 semitones or frets). The semitone differences between the 3rdand 4thnotes in the tetrachordswill naturally distancethe 3rds in the harmony.

Now we hit the“aha!” moment when we understand that we can only play one note at a time on a string.Fortunately, we laid out our major scale on thesecondstring. We will place our harmony note on thefirststring. Being guitarists, we’retwo dimensionalwe can expandvertically! I call that green line aunison line.(lot more on that later)

The 3rdnote, theE(green) in the C Major scale is the same note as the open note of the first string. A unison. We advance down the key, pairing notes of the 2 strings. The distance between C and E is a Major 3rd(4 frets) a 1 fret difference than between D and F, a minor 3rd(3 frets).

How the half step intervals from the tetrachords are distributed gives us predictable and therefore functional two-part harmonies. Next, we have paired ‘re’ theDand ‘fa’ theFskipping over the ‘mi’. Continue this pattern advancing up the scale until we complete the ‘pairing’ when ‘do’ and ‘mi’ are finally paired an octave higher.

Once the ‘Pairings” have completed, each note in the scale has a harmony note aninterval of a thirdbetween the notes on the second string and the notes on the first string. An interval is not the notes themselves but the spacebetweenthe notes, like a distance. It takes two notes to have one interval. The natural half steps between the 3rdand 4thnotes in the tetrachords determine if the 3rdwill be a major 3rdor a minor 3rd. The results of this natural ‘distribution’ of half steps gives us an important pattern. Each tetrachord has its first and last harmony be a Major 3rd(4 frets) and its 2ndand 3rdharmony be a minor 3rd(3 frets) We call each note with its harmony adegreeof the scale). We identify them with Roman Numerals, each with a purpose in allegiance to the key.

The major 3rdhas a fret range of 2 frets while the minor 3rdhas a fret range of 3 frets. The pattern that is naturally formed by the half steps in the tetrachords is:Major-minor-minor-MajorCapitol Roman Numerals for Major, small roman numerals for minor.

Eachdegreehas a function; hence it has a name within the key. This set of terms becomes our language.

To be continued…Books and On-Line Private Lessons available at 

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