Guitar Theory From First Principles, Part 2

In part 1 I made the case for learning 'Theory in Practice' and set you the task of embracing the fretboard in a variety of ways. This article takes us into the realm of the Major Scale, the source of all Western music theory. We will dispel some serious jargon and discover the key.

Take a deep breath, grab your guitar and look at your fretboard. Play the C note at 5A-3. Now play up the 5A to fret 15 string hitting DEFG ABC. This eight-note (or one octave) pattern is called the C Major Scale.


Now play this scale in all directions, ascending and descending, until your entire board is alight with CDEFGABC like the one below. I have allocated each note with a color of the rainbow.


If you look at the gaps (or intervals) between the scale notes as it ascends from C, you will discover it follows this formula: TTstTTTst; where T=tone =2 frets and st=semi-tone=1 fret. In some cases (like describing the height of string-bends) the tone= a full step and the semi-tone = half step. If you follow TTstTTTst from any note, the same pattern of frets will emerge but the note names will change e.g. try it from 6E-3 (G) and you get: GABCDEF#. Try the formulae from F and you get: FGABbCDEF.

When you describe (or spell) a major scale each letter from A to G has to be represented e.g. when you built the F major scale using TTstTTTst you might have written FGAA#CDEF as you followed the formula. This is incorrect because there is no letter B in the scale therefore A# needs to become a Bb.

Each scale has its own unique number of sharps or flats (its signature). Scale notes are sometimes referred to as the: Tonic, Super-tonic, Mediant, Sub-dominant, Dominant, Sub-mediant and Sub-tonic. Play through your C scale and recite their names in case you come across this nomenclature. The plot thickens...

Play your C scale from 5A-3 but double it up to 5A-15 and count the notes. There are two sets of eight (or octaves) therefore C=1 or 8 and F for example, would be 4 or 11. Now scatter the intervals onto other strings in all directions and play them as two-note chords (or dyads) in this order: CD, CE, CF, CG, CA, CB and CC. Listen to the way each interval blends (or harmonizes) and memorize the shapes.

In article 1 we discovered that the C chord was made of notes three notes CEG (known as the C major triad). Notice these are the first (or root), third and fifth notes of the scale and that they are three notes apart. There are other triads lurking within the major scale if you know where to look i.e. 246, 357, 468, 579, 6810 and 7911. The gaps between CEG can be described in terms of tones and semi-tones i.e. CE=4 frets=T+T and EG=3 frets=T+st. Gaps of a T+T are also known as a major 3rd interval (or 3rd). The T+st gap is a minor 3rd (or b3rd).

Now look at the FAC (4 6 8) and GBD (5 7 9) triads and you will see that their interval structures= 3rd + b3rd therefore like C, the F and G triads are also major. Now cast your gaze upon DFA (246), EGB (357) and ACE (6810). Notice the intervals=b3rd+ 3rd. This combination gives you minor triads. BDF (7911) on the other hand=b3rd + b3rd which is known as a diminished triad. In each case a triad is a stack of thirds. Play all these triads in any order all over the board. Listen to the harmonies and memorize their shapes.

Here is a summary of what we have extracted from the C scale.

Roman Greek Scale notes numbers Note names Interval structure Triad name
I tonic 135 CEG 3rd, b3rd C major
ii super-tonic 246 DFA b3rd, 3rd D minor
iii mediant 357 EGB b3rd, 3rd E minor
IV sub-dominant 468 FAC 3
rd, b3rd
F major
V mediant 579 GBD 3rd, b3rd G major
vi sub-mediant 6810 ACE b3rd, 3rd A minor
vii sub-tonic 7911 BDF b3rd , b3rd B diminished

The resultant triads produce the chord scale of C. Build these chords from their triads (or your chord book) and play them in as many ways as possible.

Let's say someone describes a tune as a "1, 4, 5 turnaround in the key of C." This means that the song follows a repetitive I IV V chord progression from the chord scale of C major i.e. Cmaj Fmaj Gmaj. The key to a song is the scale that provides its notes; be they chords, solos, riffs, bass lines, vocals, piano or whatever. Any notes that used that fall outside the scale are known as chromatic notes (colorful notes) or accidentals. A key change occurs where the composer changes to a different scale within a song. The term diatonic is used to describe music which comes entirely from a single key.

It was a bored Pythagoras who figured out all this using a length of string in 550 BC. If he had owned an Ibanez SHRG1Z I suspect he would not have got distracted by triangles. Here are some tasks designed to reinforce this theory and broaden your horizons.

1. Delve into the C chord scale for a turnaround e.g. C F G (I IV V), practice some rhythm techniques, work on the changes and record your progression into a loop station or multi-tracker. Now seek out original melodies, licks and phrases to complement the rhythm track by jamming (or improvising) over the progression with the C major scale notes and intervals.

2. Take the CAGED open-chords (including open strings) and slide them up the board in their entirety as follows i.e. move C major up 5 frets, A=8 frets, G=10 frets, E=1 fret and D=3 frets. Note how they now all have the same notes FAC, the notes of an F major triad or F major chord. Note also that all possible FAC notes on the fretboard are covered. With just a little more CAGED system knowledge and your chord book will be gathering dust.

Next: Reducing the scale to Modes or Inversions in the name of improvisation. Further exploitation of the CAGED ones.

Guy Pople is a music, education and multimedia specialist based in the UK`s North-West. He plays guitars, studies theory and runs St Annes Music in Lytham St. Annes, a one-stop shop for musicians on the Fylde coast of Lancashire. St Annes Music offers professional instruments, recording, tuition and accessories.

His live band Nomad is currently building up their original music. You can catch him
on Virtual Strangers.

Guy Pople

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