Primary Triads and Their Functions ③ / Music Theory Lesson

Author: sleepfreaks

The Function of the Dominant (D)

Previously, we took a look at the function of the Tonic and Subdominant using a number of examples.

This time, we will be using the chord made from the Dominant scale degree (for a major key, the V or V7)
to create a more dramatic chord progression.

✳︎ Sometimes only the V7 is considered to hold the function of the Dominant chord due to the fact that it contains the tritone interval.
In this article, we will be using the chord made up of the Dominant scale degree as the Dominant chord,
and will just consider the V7 as an intensified version of the V chord.

First lets check the placement and degree name of the dominant.
The dominant is shown circled in red.



Among the major diatonic chords, the D = Dominant chord has
a powerful sense of instability and tension.

Because of this, it has a strong urge to return back to the stable T (tonic) chord.
This motion from unstable→stable in a chord progression creates a sense of “completion” (especially when returning back to the I chord).

Perhaps you thought about the tritone interval after hearing the words “unstable and tense”.
Because of this reason, the V7 has a stronger pull back to the tonic than the normal V chord.


In addition, although the dominant chord has a “dominant” characteristic, having a progression from the “V,V7 → I,Imaj7”
makes the key of the track clearer to the listener as well.

Making a Chord Progression with the T / SD / D

Lets listen to some actual examples.
After the previous T→SD sample, we will move into connecting the D→T.

We will be looking at these examples in the key of C.
Be sure to note the difference in sound between the V and V7 chords as well.

  • I→IV→V→I C→F→G→C


  • I→IV→V7→I C→F→G7→C


  • Imaj7→IVmaj7→V→I Cmaj7→Fmaj7→G→C


  • Imaj7→IVmaj7→V7→I Cmaj7→Fmaj7→G7→C


What did you think?
By having the tense dominant chord in the mix, the flow and landing back on the I/tonic felt stronger,
and you may have realized that using the V7 chord made this feeling even stronger.

While making your own music, you can choose between using the V or V7 depending on how
much tension you want when moving back to the tonic chord.

Paying Attention to the Difference Between the V and V7

Previously, we used a method of extending the SD after the T, so lets try this out on the D chord as well.
In addition, we will change it to the V7 chord half-way, so be sure to listen closely.

  • T→SD→D(V)→D(V7)→T C→F→G→G7→C

Piano Only


Though the V chord was slightly tense, the V7 intensified this tension, and gave a sense of wanting to go back to the tonic.
As expected, the tritone within the V7 creates more tension than the V chord.

By drawing out this sound it becomes more obvious, but the feeling of relief when going back to the I/tonic chord is much stronger than the SD chord in our last article.

Last but not least, we will go over the functions of the T, D, and SD chords.

  • T=Tonic

The most central chord of the key. It has a powerful sense of stability, and is often used as the first and/or last chord in a progression.

  • SD=Subdominant

It functions somewhere between the T and D chord, and adds flavor and development to a chord progression.
Moving from the T to the SD gives a sense of development and gives almost a sense of “floating” within the chord progression.
When used before the D, it creates a smooth and powerful flow when leading back to the T.

  • D=Dominant

It has the most powerful pull back towards the I=T=Tonic chord.
When moving from the Dominant back to the Tonic, it creates a sense of relief from the tension
and a strong sense of completion (in particular when returning to the I chord).
To create more tension, use the V7 over the V chord.

In our next article, we will be looking at different progressions using the T, SD, and D chord, as well as learning about cadence.

Article Writer: Kazuma Itoh

講師 伊藤
After moving to the USA at 18 years of age with a scholarship from Berklee, he completed a 4 year study focused on song writing and arranging there.
Using this knowledge, he works across a variety of fields from pop music, film music, and more.