Lesson 21B

Leading to modulation part II

and cadences     

In the chapter leading to modulation, we covered Major Scale Cadences, harmonic and melodic minor scale construction. We need to continue developing the diatonic major and minor scale cadences.

Out of all the possible 7 note scales, the diatonic has the greatest number of constant intervals and the most major and minor triads. Recall that I’ve stated the Diatonic Major scale has 3 major, 3 minor triads with only 1 tri-tone, diminished 5/ Augmented 4^th. Count each of the minor and major chords in the key of C Major below.

C, Dm, Em, F, G, Am, B diminished.

The diatonic and melodic scales are the only scales with two types of second, the major second and the minor second (whole step – half step). Since the Diatonic scale has few dissonant intervals, it is well adapted to both melodic and harmonic music. The constant triads tend to create a melodically smooth passage with only 2 steps, (whole and half).

We know now that there are seven modes to each major key. Out of these 7 modes, only two are capable or effective in creating harmonic music. For a scale to be effective, it must have a tonic triad. (Tonic triad, brings closure and completion). Out of the seven modes in the major key, the two modes that can effectively accomplish this are the Ionian and Aeolian modes. Don’t forget the Ionian and Aeolian modes are the 1^st and 6^th in every major key.

In the key of C major, these two chords would be the (I and vi) (C and Am). Recall the chords in the key of C major, C, Dm, Em, F, G, Am, B dim, C. In the key of C major, C would be the (I or Tonic triad and in the Am scale, Am would be the (vi or tonic triad).

The major scale is a powerful scale and can create a very powerful tonic function. The (I chord) is a powerful chord in the major key. When the (I – Tonic chord) is played in the root position not inverted, it will produce a very effective tonic or final function. It will bring the progression to a sense of closure or completion. If you played the (I chord) in the 1^st or 2^nd inversion, it would weaken or delude its tonic function. It will be like, okay what’s next? The (vi chord) is often used as a deceptive cadence. It will sound okay, but it is still waiting for the (I chord) for full resolution.

For example, in the key of C major using the Am scale, the Am will do basically the same thing as far as being a tonic chord, but not as powerful or decisive as the C chord. Since the Am or Aeolian mode has a less decisive cadence, it is generally avoided in classical music. You may find the harmonic minors used in common practice. However, the Aeolian mode is often used in popular music. The Aeolian mode can also drift very easily back to the relative major so care must be taken in chord changes, unless you want to switch back to its relative major. We will cover that subject down the road. As you play these modes you will begin to hear their medieval or ancient qualities. Before the 1600’s, music was written using modes.

Okay, what does this mean to me, you ask? To better understand what is going on, we need to start from the beginning.

Cadence or progression is a pattern of chords that resolve on to a chord of rest or resolution. A final chord or tonic chord. A progression must consist of at least three triads if a seventh, diminished or augmented chord is not being used. You must use at least three chords in a progression, if they are only major or minor chords. You can create a two chord progression if you use the diminished, augmented or dominant 7 chords. For now, we will be covering progressions using only diatonic major and minor triads of the scale. We will eventually get to the harmonic and melodic progressions.

Before we begin you must be up on roman numerals. From now our progressions will be illustrated using roman numerals. All major and minor keys will be illustrated the same way. Major chords get the Large Caps, and minor chords will get small caps. Look at the key of C major illustrated below.

The key of C major and G major have been illustrated, but I could have used any key to do this.

I, ii, iii, IV, V, vi, vii° , in the key of C major these roman numerals represent:

C, Dm, Em, F, G, Am, B°  

Or

G, Am, Bm, C, D, Em, F#° in the key of G major.

This means if I give you a I, IV, V Progression in the key of C major you would play the chords:

C, F, G 

 Or G, C, D in the key of G major.

If we are working on the Am scale, Am, B°, C, Dm, Em, F and G this progression would be shown as:

i, iv, v  or Am, Dm, Em, 

The little circle (° ) is often used to represent the diminished chord.

It's time now to work on a few progressions in the of C major and Am. The first progressions are those in the key of C major and using the C chord as the tonic or final chord.

Practice each of these progressions and listen to how they resolve. Notice that the progressions in C major are more conclusive and have more closure. Learn them all and convert each of these progressions to other keys. Play them in G major and E minor. A major and F# minor, F major and Dm, D major and Bm. Play them in all the keys and come up as many others as you can. We will cover more about cadences, but you have a lot of work a head of you.

Assignment

Good Luck,