Lesson Two: Common Tones

Lesson Activity

The lesson will begin by listening to four songs featuring the “vi-IV-I-V” (read as 6, 4, 1, 5) chord progression. This ubiquitous progression is found in hundreds of modern pop songs due to how easily it pairs with simple and effective melodies.

Encourage the students to think about and discuss whether the songs sound similar because they share a progression, or different because of the arrangements and instrumentation.

Next, using the C major scale, show how the notes of these chords interact and model it on the piano:

E         C         G         D                                Mi       Do      Sol      Re
C         A         E         B                                 Do      La       Mi       Ti
A         F          C        G                                 La       Fa       Do      Sol

If class size allows, have students watch your hand on the piano as you play the chords in root position. Have them note how much your hand has to move between each chord.

Next, invert the chords to maximize common tones and minimize movement:

E         F          E         D                                 Mi       Fa      Mi      Re
C         C         C         B                                 Do      Do      Do     Ti
A         A         G         G                                 La       La      Sol     Sol

Again, model this on the piano, emphasizing the difference in efficiency, and making note of common tones. You can also use Chrome Music Labs for a clear visual representation of the two versions of this progression:

A visual representation of the vi-IV-I-V progression made in Chrome Music Lab, played first in root position and then played again in a more efficient inversion that makes use of common tones. Note that the colours of the notes match the colour scheme of Boomwhackers, if you choose to use those.

DISCUSSION: Does one version sound better than the other? Why?

Now break the students into three groups, and assign them the lower, middle, and upper voice in the chord. Model each part as it moves through the progression. Have each group sing their part together, then provide all three notes at once with either the piano, Music Lab, or your voice. Cuing each chord change, have the students sing all three parts together to create the chord progression.

DISCUSSION: Do the common tones sound or feel any different when the surrounding notes change? Why do you think a songwriter or composer might prefer to structure their chords to use common tones, or why might they avoid them in some cases?

Lesson background

This lesson, designed for a grade 11 class, builds off students’ existing understanding of basic chord theory, scales, and at least a working knowledge of solfège. Designed to occur shortly after a lesson on chord inversions, this lesson aims to teach one of the advantages of using inversions: common tones.

Common tones occur in a chord progression when one or more elements or voices within the harmony does not need to move. While this can happen by chance when playing a progression in root position, it can be encouraged by selecting chord inversions that allow for as much overlap as possible. Common tones create a much simpler motion between chords, requiring minimal hand movement on the piano or allowing for a single note to be sustained vocally.

Additionally, common tones are very pleasing to the ear, creating a fascinating phenomenon wherein the quality of the sustained common pitch seems to change based on the motion occurring around it. This can be a very powerful tool when writing melodies as well; exploiting common tones between chords can allow for a static melody that seems to transform as the chord changes. The example song “Say Something” has an ostinato note that is a very clear example of this.

Understanding common tones and inversions is extremely valuable for students beginning to explore composition and songwriting.