Greg's Music Theory Page


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SCALES

Guitarists, click here for detailed tablature of scales

Click here for a list of all of the major scales and their respective key signatures.

Most musicians choose a scale to play a lead/melody which is derived from the key (or implying key(s) of the underlying chord progression(s). However, more progressive styles of Jazz take exception to this method, deriving scales from the immediate underlying chord or progression as opposed to keys. But in most other styles of music, a lead/melody can be chosen based upon the key of the song or progression. The subsequent text will focus on the first method. Using this method as a building block, a musician can then, if desired, learn the more progressive jazz method as well.

When you are ready to explore the second method, I recommend Marc Sabatella's A Jazz Improvisation Primer".


See the keys section as an aid to this section.
SOME DEFINITIONS
Scale
A group of notes, (no note is repeated) in which melodies/leads are derived.
Diatonic Scale
A seven-note scale consisting of half-step and whole-step intervals. See intervals subsection of the chords section.
Pentatonic Scale
Loosely defined as a five note scale, the pentatonic usually refers to the specific 5 note scale derived from the major and natural minor scales.
Tonal Center
The note in which all of the chords in a song or progression "revolve" around. This note will sound most "at rest", yielding the least dissonance. The tonal center is usually the same note as the major or minor key. When the key and the tonal center differ, modes are used.

Using the circle of fifths to construct a diatonic scale one can derive all of the scales needed to play leads/melodies.

To understand scales more in-depth, we need a basic understanding of intervals, located within the chords section.

Major Scale

A major scale consists of the following intervals:

  • Whole Whole Half Whole Whole Whole half

A natural minor scale scale consists of the same interval sequence with a different starting point.

  • Whole Half Whole Whole Half Whole Whole

Click here for a list of all of the major scales and their respective key signatures.

Relative Minors

Every major scale has a corresponding relative minor scale. A relative minor is a minor scale consisting of the same notes (key signature) as it's relative major.

For example; A minor is the relative minor of C major. Compare:

  • C D E F G A B - C major
  • A B D E F G A - A minor

Another example; D major is the relative major to B minor. Compare:

  • D E F# G A B C# D - D major
  • B C# D E F# G A B - B minor

Notice that in both examples, both scales contain the same notes, and therefore share the same key signatures, but have different starting points. In the last example, both the D major and B minor scales have 2 #'s, C# and F# as their key signatures.

The 3 types of minor scales

There are 3 types of minor scales. The harmonic minor, melodic minor, and natural minor.

Natural minor
The natural minor is the most common scale, because it is simply the major scale starting on the 6th scale degree. (B minor is the D major scale starting on the B, it's 6th scale degree.) Whenever you see a scale that is just labeled "minor" without the "natural", "harmonic" or "melodic" labels preceeding it, it is safe to assume that this is a natural minor scale.
Harmonic minor
The natural minor scale with a raised 7th scale degree. (A B C D E F G# A)
Melodic minor
The natural minor scale with a raised 6th and 7th scale degrees (A B C D E F# G# A)

The Pentatonic Scale

The Pentatonic Scale is a five note scale, derived from the seven note diatonic scale. There is a major and minor pentatonic scale. The major pentatonic, derived from the major diatonic scale, is voiced 1, 2, 3, 5, 6. An example is C D E G A. The minor pentatonic, derived from the minor diatonic scale, is voiced 1, 3, 4, 5, 7. An example is A C D E G. The Pentatonic scale is very popular in rock and blues. It is also interesting to note that this scale is also used in Eastern Asian music, especially in Chinese music.

The Blues Scale

The "blues scale", or blues pentatonic is just a minor pentatonic with an additional note (b5) making it a hexatonic (6 note) scale.

A C D E G - A Minor Pentatonic
A C D Eb E G - A Blues pentatonic.

Applying scales

This leads us to learning how to apply scales to musical contexts. The traditional method is to simply find the key signature of the song/progression and play the corresponding scale. If the song/progression is in the key of Bb major, the Bb major scale can be played over top of the corresponding song/progression. Also, the Bb major pentatonic scale can be used, since it is a derivative of Bb. In fact, any scale derived from the Bb diatonic, would work, in the key of Bb.

Modes

A mode is
a scale, derived from either the major, natural minor, harmonic minor or melodic minor scales, that is played starting on a note different than the tonic.
Another way of thinking about it is:
a scale, derived from either the major, natural minor, harmonic minor or melodic minor scales, that has a tonic that is different from the key.

The following is a list of modes for the C major scale:

  • C D E F G A B - Ionian
  • D E F G A B C - Dorian
  • E F G A B C D - Phrygian
  • F G A B C D E - Lydian
  • G A B C D E F - Mixolydian
  • A B C D E F G - Aeolian
  • B C D E F G A - Locrian

You've already learned one mode, the natural minor scale(aeolian). A minor is a mode of C major.

Learning the names of the modes is perhaps, half the battle, but don't get hung up on them. They are only beneficial to the student in so much as they provide a means of communication.

Their are three ways that I suggest to learn modes. One, to become better acquainted with this subject, is simply to play the modes as listed above.

The second way is to compare each of the modes with it's major or minor counterpart.

Take a look at the modes once again. This time I've added the major or minor label next to each mode. This indicates whether or not the mode most most closely resembles the major or minor scale.

  • C D E F G A B - Ionian (Major)
  • D E F G A B C - Dorian (Minor)
  • E F G A B C D - Phrygian (Minor)
  • F G A B C D E - Lydian (Major)
  • G A B C D E F - Mixolydian (Major)
  • A B C D E F G - Aeolian (Minor)
  • B C D E F G A - Locrian (Minor)

Notice that the list of resembling scales for these modes, aside from the locrian, matches the pattern found in the number system.

* The locrian corresponds, in the number system, with the diminished chord, but since a diminished chord is simply a minor flat 5, we will think of it as a minor scale for simplicity's sake.

So the Ionian, Lydian, and Mixolydian scales can be compared to their corresponding major scales with the same root, and the Dorian, Phrygian, Aeolian and Locrian, scales can be compared to their corresponding minor scales with the same root as follows:

MODE CORRESPONDING SCALE MODAL DIFFERENCE
A Ionian A major Same scale
A Dorian A minor Minor w/#6
A Phrygian A minor Minor w/b2
A lydian A major Major w/#4
A Mixolydian A major Major w/b7
A Aeolian A minor Same scale
A Locrian A minor Minor w/b2 and b5

The third way to learn how modes sound is to play them over their corresponding major, minor or diminished chord. If you play just an F lydian mode, it will sound like a C major chord starting on F. But, if you play this same mode over an underlying F major chord, the character of the lydian mode will "jump out".

Because the modes are so close to their major or minor scale counterparts, it is essential for the musician to emphasize the note which distinguishes the mode from it's counterpart. For instance, since C lydian is a C major scale with a sharp 4 (F#), it is important for the musician to emphasize the F# when playing this scale. Otherwise, the listener is more likely to hear a C major scale instead.

Applying modes

One way to apply a mode is within a "modal chord progression". A modal chord progression (my contrived term) is a chord progression within a song which deviates from the key of the song and allows for a mode to be applied.

"Amazing Grace" has the following chords in it.>

G major, G major, C major, G major, G major, A major, D major

This song, in the key of G major has one chord which deviates from the key. A major. The A major (A C# E) chord is functioning as a II chord. II's chords are minors within major keys. The C# is not within the key of G. G has only one sharp, F#. A G major scale would work for this whole song, even over the A major if one does not linger on the the C note of the scale, thus yielding dissonance.

But, another option, is when the A major chord is encountered, the G lydian mode can be used. The G lydian is the D major scale starting on it's 4th scale degree (G). Why call this scale a G lydian instead of just D major? Because the tonal center of the progression is G.

Another way of looking at this progression is to think of the A as temporarily modulating the song to the key of D major. Either way, you get the same results, but it's easier for most people to think modally.

Using Pentatonic Scales Over Modal Chord Progressions

Even though I said that in Amazing Grace, the major or ionian scales can be used over the song's chord progressions, the actual melody of the song is derived exclusively from the major pentatonic scale.

The pentatonic scale holds a unique place among modal chord progressions because all of its missing notes (major pentatonic = major scale minus the 4th and 7th scale degrees) are notes that distinguish the major scale from major modes and minor scale from minor modes (comparing minor pentatonic to minor modes).

So if you're playing a lead over top of a song that has a modal chord progression and you know the song has a major or minor tonality, one option you have is not to worry about what mode(s) the song's chord progressions are following and simply play the corresponding pentatonic scale. This is especially useful when the song is shifting modes.

Joe Satriani uses a technique that he calls "Pitch Axis Theory" to compose a song using one tonal center, cycling through multiple modes in the same song. So a song may be in the key of E, but have chord progressions and melodies that cycle through E ionian (major), E lydian and E mixolydian.

Now while he uses this primarily as a lead technique, let's say you're jamming with Satch and he asks you to take a solo. Instead of you having to know all of these modal changes, you could simply play E major pentatonic over the entire lead. Now granted, Satriani usually goes one step further and will use parallelism also, meaning that he switches tonalities from major to minor so you might need to jump from say, E major pentatonic to E minor pentatonic, but the point is that the major pentatonic scale will work over ionian, lydian and mixolydian chord progressions, while the minor pentatonic scale will work over dorian, phyrgian, and aeolian chord progressions.

Composing music using modes

The subject of modal chord progressions leads us to an important point in regards to composing music using modes. Just as we noted earlier that it is necessary to emphasize the note(s) that distinguishes a mode from it's major or minor counterpart, so it is equally important to emphasize the chord that distinguishes a modal chord progression from it's major or minor counterpart.

Keeping in mind the pattern mentioned in the Number System section, where I IV and V are major, ii, iii and vi are minor, and vii is diminished within a major key, if we were to play or write a song that utilized a mixolydian chord progression, the numbers would be I IV and bVII are major, ii v and vi are minor, iii is diminished. Here are the chords of C mixolydian as an example:

  • I - C E G - C Major
  • ii - D F A - D Minor
  • iii - E G Bb - E diminished
  • IV - F A C - F Major
  • v - G Bb D - G Minor
  • vi - A C E - A Minor
  • VII - Bb D F - Bb Major

If you merely played the I, ii, and IV and vi chords in this song, there would be no distinction between this being a mixolydian chord progression as opposed to a standard major chord progression. Therefore the differences need to be emphasized. The differences between a major progression and a mixolydian progression are the ii diminished, v minor and the VII major. I've gotten to a point now that whenever I see these chords in what appears to be a major chord progression, I automatically associate it with mixolydian.

For a lydian progression, the II major, the #IV diminished, vii minor chords distinguish it from a major (Ionian) progression. All the modes have certain chords that need to be emphasized to distinguish them from a major or minor scale. Find those chords and exploit them.

Scale and lead ideas

Here are some general ideas to develop your lead playing.

There are 3 basic elements to playing lead.

They are:

  1. Scales
  2. Arpeggios
  3. Intervals

1. Scales

Learn to play these in sequences/patterns. Take the notes out of their straight order. I tend to number the notes of scales, numbering the tonic as 1, etc. I then will play scales according to numbered patterns. For instance, if I'm working with the F major scale, F is 1, G is 2, etc.

Here are some examples of numbered patterns

  • 1 2 3 4, 2 3 4 5, 3 4 5 6, 4 5 6 7
  • 1 3 2 4 3 5 4 6 5 7 6 1
  • 1 2 3, 2 3 4, 3 4 5, 4 5 6, 5 6 7
  • 1 2 3 4, 3 4 5 6, 2 3 4 5, 4 5 6 7

These are just for starters. I'm sure you can come up with more on your own.

And finally, you may want to experiment with scales that contain notes which are "outside" of the key of the underlying song/progression. "Playing outside" can add some color to an otherwise dull melody/lead. The blues scale is a scale which contains one note which is "outside" of the minor key. Don't limit the blues scale to minor keys. Even though it's is based upon the minor pentatonic, it also works great when played over songs in major keys, giving them a blues feel.

2. Arpeggios

Arpeggios are simply broken up chords. For instance, by playing the notes of the D major chord, D F# A, one is playing the D major arpeggio. Arpeggios can be chosen based upon the key of the song/progression or the immediate underlying chord. One exciting way to use arpeggios is to choose one which enlarges a chord. For instance, playing the b diminished arpeggio over a G major chord, produces the sound of the G dominant 7 chord, even though neither the chord or the arpeggio *alone* is playing G 7. Arpeggios do become more like scales if they are derived from chords which are bigger than 4 notes. This is because chords beyond 4 notes tend to transcend octaves. My favorite arpeggio is the Minor 7 arpeggio, because it is so close to the famous pentatonic scale. Compare:

  • A C D E G - A minor pentatonic
  • A C E G - A minor 7

3. Intervals


* See the Intervals subsection of the Chords section for more detailed information.

Intervals can be played two ways. They can be played together, like a chord, or separate, like an arpeggio. Intervals can break up the monotony of scales and bring a "freshness" to any, otherwise predictable lead. One easy way to find some appropriate intervals for a song is to derive them from the key of the song/progression. Of course, one can also play intervals which aren't in the key.

I love the guitarist, Eric Johnson's approach to intervals. He plays them by skipping strings, and playing them in groups of three. One interval that he plays a lot is voiced, 1, 5 9. This is the outline of a ninth chord and works well over major or minor chords.