Electric Guitar 104 – G Major Scales, Chords, Key, Triads, and Progressions

G Major – The Key, Chords and Scale of G Major.

This is the companion post to the video: Electric Guitar 104 – G Major on my YouTube channel http://www.youtube.com/lessonswithcameron

In this post, I want to cover one of the more common keys in songs played on the guitar.  Because of the way the guitar strings are laid out, the instrument lends itself perfectly to keys like G, Em, Am, A, D, and E.  For this reason, you’ll see a large majority of songs written on guitar being in those keys.  So, with that in mind, we are going to explore G Major.  (Remember, all major keys are built in the same way, so the relationships between the chords and notes is true for all major keys.  If you see it, great.  If it isn’t apparent to you, prepare to learn each key individually until it becomes clear.)

Definitions.  For the purpose of this post, I’m going to use three words and I’d like to define the way I will be using them here.  (These are shortened definitions, as the terms have much deeper meanings.)

Scale: A series of notes defined by their whole step and half step intervals.

Chord:  3 or more notes played together.  In this case, each chord will be made using every other note in the scale.

Key:  A series of chords based on a scale.

The Key of G uses the scale G Major (G A B C D E F# G) and the chords G Am Bm C D Em F#m7(b5) G.

The major scale is made using a series of whole steps and half steps.  We can break the scale up into two halves called “tetrachords”.  Each tetrachord of a major scale is Whole Step, Whole Step, Half Step.  A major scale is made by joining two tetrachords with a Whole Step.  Using these intervals, the major scale is made of these intervals:

1  W  2  W  3  H  4  W  5  W  6  W  7  H  1

If we explore this from the G string, we can find these notes on the following frets:

0 – 2 – 4 – 5 – 7 – 9 – 11 – 12  These notes are G A B C D E F# G.

By moving over to the next string every four or five frets, you can play a Major Scale in one position without moving your hand up and down the neck.  The following diagram shows two octaves of the G Major scale in the first position using open strings.  Use your index finger on any notes on the first fret, your middle finger on any second fret notes, your ring finger on all third fret notes and your pinky for the note on the fourth fret, fourth string.

Each note in the scale is represented by a chord.  These are the majority of chords you’ll find in song that is in a certain key, which is why it is useful to know your keys.  This means you will be able to learn songs quickly by only having to learn the sequence of chords, instead of memorizing a new set of chords each time and not being sure what to expect.

Triads:  The basic set of chords in a key are called triads.  They are made using two notes that are a third apart (1 and 3, in this case G and B) and a third note that is a third above the 3.  (The 5th note from the 1).  We call these notes a triad.  (1-3-5).

Triads are built on thirds, so it’s important to understand what thirds are and how they work.  There are two basic kinds of thirds: Major and Minor.  Major Thirds are 2 whole steps (4 half steps), and Minor Thirds are 1 1/2 whole steps (3 half steps).

There are four types of triads: Major, Minor, Augmented and Diminished.  Each of the four types of triads are built by stacking the two different kinds of thirds.

Major Triad (M):  Major 3rd + Minor 3rd

Minor Triad (m):  Minor 3rd + Major 3rd

Augmented Triad (+):  Major 3rd + Major 3rd

Diminished Triad (dim):  Minor 3rd + Minor 3rd

Starting from the Root Note of the key of G, we are going to take every other note from the scale to build our first triad.  1=G  3=B  5=D.  (G1 A2 B3 C4 D5 E6 F#7).  If we measure the distance from G to B, we find it is 2 steps.  The distance from B to D is 1 1/2 steps.  This combination of Major 3rd (M3) and Minor 3rd (m3) makes a Major chord.  This would then define the first chord of the key (I) as G Major.  We could then go to the second note of the scale “A” and repeat the process.  This gives us the notes 2=A 4=C 6=E.  Measuring A-C-E, we find the pattern m3+M3.  This identifies a minor chord, so the 2nd chord of the key (ii) is “A Minor” or Am.  You can repeat this process through the scale.  I recommend doing it on paper and discover what is contained in each chord for yourself, while looking to discover patterns.

We number the chords from one to seven (one for each note of the major scale) using roman numerals.  Upper case roman numerals would indicate a major chord (I, IV, V) and lower case roman numerals would indicate minor chords (ii, iii, vi).  After examining the key of G Major (or any major), we will find this pattern of chords:

I  ii  iii  IV  V  vi   viidim

When we apply the G scale to these chords, and adjust them to Major and Minor according to the roman numerals, we find these chords to be in the key of G Major.

GM  Am  Bm  CM  DM  Em  F#dim  GM

The most common chords found in nearly any song are the I IV and V chords.  We call these chords the Primary Chords of a key.  If you play any song in G, you can expect to spend a good amount of time strumming G, C and D.

Common chord progressions are some series of chords that are found on many songs.  It is important to remember that what makes a song is a melody (the scale being used by the vocalist or instrumentalist) over the top of the chords (harmony), which only exist to serve the melody.  Chord changes can not be copyrighted, however melodies can.  This is why many songs use the same chord progression, though in the end do sound quite different.   Here are some easy and common progressions to get you strumming.

Each roman numeral indicates a measure of strumming.  For simplicity, you can just strum each chord four times and then move on to the next.  Repeat each progression several times, mix the progressions together, or experiment with the chords to find new progressions you like.

I    IV    V    I      (G    C    D   G)

I   V   IV   I    (G   D   C   G)

I    IV    V   IV   (G   C   D   C)

I    V    vi    IV   (G  D  Em  C)

I   vi    IV     V   (G   Em   C   D)

Thanks for tuning in.  – Cameron

Dominant Scale (Mixolydian Scale/Mode)

The Dominant Scale is the same as series of notes as the Mixolydian scale. It is also the same series as the Major scale, except the seventh note is lowered a half step. This scale works well over the dominant seventh (e.g. C7, G7, A7, etc).

1 W 2 W 3 H 4 W 5 W 6 H b7 W 1

Examples:
C Dominant = C D E F G A Bb C (Play over C7)
F Dominant = F G A Bb C D Eb F (Play over F7)
A Dominant = A B C# D E F# G A (Play over A7)

Modulation.

Modulation is the process of changing keys within a composition. In classical theory, certain key changes are often dictated by the form of a piece. In jazz, modulation is a common method of creating intense, interesting and difficult progressions. In pop music, modulation is used to gain certain changes in mood to achieve certain pop standards of composition. Modulating can be complicated or quite simple, depending on the desired effect. In this post, I would like to address one of the simplest modulations and hope to open a door to understanding the basic idea behind it, and give a peek into the idea of simple chord substitution.

Modulating from major to relative minor using simple chord substitution.
For the purpose of this discussion, we will use the sample, relative keys of C Major and A Minor. To keep the example as simple as possible, we will use the I, IV and V7 chords of each key.

C Major: I = C Major (C). IV = F Major (F). V7 = G7.
A Minor: I = A Minor (Am). IV = D Minor (Dm). V7 = E7

Since theses are relative keys, this will be a pretty simple and seamless modulation. The key to this working is the V chord of each key. The two keys contain the same sets of notes, with the only exception being the notes of the V7 chord. To make a long story short, when you play the G7, your ear will expect the C next. When you play the E7, your ear assumes the next chord is Am. In the E7 chord, you will find the G# note. This note is the leading tone of A, and your ear will expect it to resolve to an A next. So, here are two sample progressions. First I will show you the two independent progressions, and then we will arrange the chords to logically lead your ear to move the I from C to Am.

| I | IV | V7 | I |

CM progression:
| C | F | G7 | C |

Am progression:
| Am | Dm | E7 | Am |

Now to blend these together fairly seamlessly, we will use the E7/G# chord and slide the root right into an A. (E7/G# means to play an E7 chord with a G# bass. This would mean the lowest sounding note of your chord should be G#. Consult fingering charts or a reference manual like the Guitar Grimoire Chords and Voicings book for a fingering that suits your tastes.)

To join these progressions, we will insert the following progression between the two which will guide the listener’s ear to the new key.

| C | F | G | E7/G# |

We are substituting the chord E7 (The V7 of the new key) instead of the normal E minor chord for the C Major’s III chord. This leads the ear to A minor, where you can continue the above minor progression. The sequence would look like this:

| C | F | G7 | C |
| C | F | G | E7/G# |
| Am | Dm | E7 | Am |

To return to C, we will use the very common ii-V-I progression and we should be able to return to C in a natural sounding way. Assuming we are still in Am, we will start the progression from the Am. The progression would then look like this:

| Am | Dm | G7 | C |

The final sequence would look like this:

| C | F | G7 | C |
| C | F | G | E7/G# |
| Am | Dm | E7 | Am |
| Am | Dm | G7 | C |

Hopefully, this gives some insight into substituting chords to open the door to changing keys. There are many more ways to change keys and a seemingly infinite number of chord substitutions. The purpose here is to demonstrate a couple simple ways to achieve some very common modulations.

Until next time, rock on and stay tuned.