Have you ever looked for guidelines about writing a chord progression. Have you ever wondered if certain chords are better suited to starting or ending a chord progression. Have you ever tried to add variation to a chord progression which is sounding repetitive. If so, you may have been searching for theories about Chord Functions. Chord Functions can help you select your chords "with intent".
Each Musical Scale has a set of chords or Triads which have been defined as fitting the scale. Using these chords in a chord progression allows you to compose "in key". In a Diatonic Scale, there are seven Triads which can be used in any combination to create a chord progression. Each chord is given a Scale Degree name, which is defined by its position or scale degree number within the scale.
Below are listed the seven Scale Degree names of a Triad within a scale.
Scale Degree Name
Leading tone (Major scale) / Subtonic (Natural Minor Scale)
Below are the Triads in the key of A Natural Minor.
Scale Degree Name Scale Note Triad
Tonic A A minor
Supertonic B B diminished
Mediant C C major
Subdominant D D minor
Dominant E E minor
Submediant F F major
Subtonic G G major
Using the Table above, you have a list of Triads which can be used to write a chord progression in A Natural Minor. Now, we can discuss how each differs in its characteristics or function within a scale.
The Tonic Triad is regarded as the Tonal Centre and strongest harmonic point of a Scale. It is traditionally the final destination of a chord progression, giving it a sense of completion and resolution. It can also be a great first chord in a progression as it provides a strong place to start from. Starting with the Tonic also sets up the key from the opening. As an alternative, many chord progressions avoid starting or ending with the Tonic Triad to create a sense of unresolved tension. This lack of resolution can create an interesting transition from the last chord to the first as the progression repeats.
The Dominant Triad is often considered the next strongest triad in the scale. It's often considered a natural choice to go to or from the Tonic and can provide a great amount of contrast to the Tonic.
The Subdominant Triad is another strong Triad in the scale and is one of the three Primary Triads, along with the Tonic and Dominant. In a Tonic-Dominant chord progression, the Subdominant can offer additional variety and complexity. In a chord progression where you're expecting to go to the Tonic, the Submediant can be a great substitute. For example, if the listener is expecting to hear the last chord as the Tonic (and hear a resolved ending), you could use the Subdominant instead to add surprise and avoid the expected resolution of the Tonic.
The Submediant can seem like an opposite twin to the Tonic. They share two notes, so have a similar harmonic sound. Yet, in a Major or Minor (Natural) scale, when one is a Major triad, the other will always be Minor. This makes the Submediant a great substitute for the Tonic, as it can change the mood of a progression, when the Tonic is expected. It can also act as a substitute for the Subdominant triad, as they also share two notes in common.
The Mediant Triad is comparable to the Tonic-Submediant relationship. Sharing two notes with the Tonic, the Mediant can reverse the mood when used as a Tonic substitute. It's also an interesting substitute for the Dominant which it shares two notes with.
The Triad on the seventh Scale Degree of the Scale is determined by whether the scale is Major or Minor. In a Major scale, it will be the Leading Note triad, while in a Minor (Natural), it will be the Subtonic Triad. Both share two notes with the Dominant and are interesting Dominant substitutes. They are great for moving to or from the Tonic. In the Minor scale, the Subtonic is regularly relied upon for strength.
The Supertonic Triad is most used for moving between Triads with more weight or resolution (like the Tonic or Dominant). It works well as a substitute for the Subdominant and Subtonic Triads, sharing two notes in common.
Below is a list of possible Triad substitutions.
TONIC: Submediant / Mediant
DOMINANT: Mediant / Leading Note / Subtonic
SUBDOMINANT: Submediant / Supertonic
So, the Triads in a Scale each have certain characteristics. A knowledge of these characteristics can help you choose "the right Chord for the right job" and can provide valuable insight to you when you're writing your next chord progression.