• Here Are Quick Insights On Tertian Harmony

    in Beginners,Piano,Theory

    In today’s lesson, we’ll be exploring the tertian harmony – an interesting subject in harmony.

    Every musician must have a knowledge of harmony irrespective of their instrument, and this is because harmony is an integral part of music that provides accompaniment for melody.

    Before we get into tertian harmony and its application in the formation of chords, let’s talk about harmony.

    A Short Note On Harmony

    There are twelve notes:

    …(aka – “pitch-classes“) on the piano.

    Music is made by the relationship between these notes, which can either form a melody or a harmony. The relationship between notes that are heard separately forms melody, while the relationship between notes that are heard at the same time forms harmony.

    Harmony can be formed when a choir is singing. The relationship between the notes sang by the various voice parts – soprano, alto, tenor, and bass, produces harmony.

    When notes are played/sang/heard together (in harmony), the relationship between the notes are usually agreeable and pleasant, however, there are situations where the relationship between the notes are harsh and unpleasant.

    The harmony between agreeable notes is said to be consonant, while the harmony between disagreeable notes is said to be dissonant.

    The relationship between notes played/sang/heard together (in harmony) can either form intervals or chords. An interval is formed by the relationship between two notes, while a chord is formed by the relationship between three or more notes.

    Submission: Although intervals and chords can either be melodic or harmonic, their harmonic forms are our interest in this lesson.

    Now that we’ve covered harmony, let’s take this study to the next level by taking a look at a special class of harmony known [to music scholars] as the tertian harmony.

    A Treatise On Tertian Harmony

    The harmonic relationship between notes can be consonant or dissonant. Although, dissonant harmonies have their place in contemporary music, consonance has a common place.

    Several centuries ago when musicians were mostly church men, consonant harmonies were considered suitable because they have a sense of repose, stability, and pleasantness, that dissonant harmonies don’t have.

    In this segment, we’ll be looking at two important intervals that are commonly used in harmony – third and sixth intervals.

    “What Are Third Intervals?”

    A third interval is basically an interval that encompasses three letter names. For example, there are three letter names between C and E, – they are C, D, and E:

    …consequently, the interval C-E:

    …is a third interval.

    There are various qualities of third intervals, which include:

    • The major third
    • The minor third
    • The diminished third
    • The augmented third

    …however, major and minor third intervals are the commonly used third intervals because they are consonant, as opposed to diminished and augmented third intervals that are dissonant.

    Suggested reading: A Lesson On The Four Know Qualities Of Third Intervals.

    “What Are Sixth Intervals?”

    A sixth interval is an interval that encompasses six letter names. In the interval C-A:

    …there are six letter names in-between between C and A:

    …they are C, D, E, F, G, and A:

    …consequently, the interval C-A:

    …is a sixth interval.

    The Relationship Between Third And Sixth Intervals

    The relationship between third and sixth intervals is connected to the inversion of intervals. The inversion of a C-E (a third interval):

    …produces (E-C):

    …a sixth interval. All third intervals have sixth intervals that they are related to, consequently, tertian harmony (which is based in third intervals) can also be associated with sixth intervals.

    Harmonization Using Third And Sixth Intervals

    Thirds and sixth intervals are related and can be used in the harmonization of the major scales and melodies. Let’s take a look at two ways of using thirds and sixth intervals in harmonization.

    In the key of C:

    …C (the first tone of the scale):

    …can either be harmonized by a note that is a third or a sixth below it. Harmonizing C with A (a third below):

    …or C with E (a sixth below):

    …are two long-established options that C can be harmonized with.

    Conversely, you can also harmonize C with A (a sixth above):

    …or C with E (a third above):

    Attention: In both cases, we’re harmonizing C with E and A (which are a third and/or a sixth apart from C.) The E note used to harmonize C can either be a third above, or a sixth below it, while the A note used can either be a third below or a sixth above.

    “Here’s The Harmonization Of The C Major Scale Using Thirds…”







    “The Harmonization Of The C Major Scale Using Sixths…”







    The Application Of Tertian Harmony In Chord Formation

    According to Jermaine Griggs, “intervals are the building blocks of chords.” Tertian harmony (which is a product of third intervals) can be used as building blocks in the formation of chords.

    In the key of C:

    …beyond harmonizing C with E:

    …another third interval can be added above C-E:

    …which is G:

    …to form a collection of three related notes, known as a chord. Simply put, stacking notes together in third intervals (aka – “tertian harmony”) forms chords.

    When chords are classified according to their width, they fall under three categories:

    • Triads
    • Seventh
    • Extended

    Let me show you how the tertian harmony can form these various chords.

    Formation Of Triads, Seventh, And Extended Chords

    Using the C major scale:

    …we can form triads, seventh and extended chords.

    Starting from C:

    …adding a third (E):

    …and another third from C-E:

    …which is G:

    …produces a triad (the C major triad):

    Attention: A triad is a chord of three notes.

    The addition of another third interval (in tertian harmony) to the C major triad (C-E-G):

    …which is B:

    …produces a seventh chord (the C major seventh chord):

    Attention: A seventh chord encompasses seven scale degrees.

    Beyond the width of the C major seventh chord:

    …lies extended chords.

    Adding another third to the C major seventh chord (C-E-G-B):

    …which is D:

    …produces a ninth chord (the C major ninth chord):

    The width of the C major ninth chord can be extended by adding another third to C-E-G-B-D:

    …which is F:

    …to produce an eleventh chord (the C major eleventh chord):

    Beyond the width of the C major eleventh chord:

    …lies the C major thirteenth chord:

    …which is formed by the addition of another third to the C major eleventh chord (C-E-G-B-D-F):

    …which is A:

    Attention: Ninth, eleventh, and thirteenth chords are all extended chords because they exceed the compass of one octave and can be challenging to play with the average human hand.

    Final Words

    Tertian harmony is the backbone of various chord classes ranging from triads, to seventh, and extended chords. Due to the fact that it is based in third intervals, I’ll appreciate it if you invest more time in learning four known qualities of third intervals.

    We’ll continue our discussion on tertian harmony in another post.

    See you then!

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    Onyemachi "Onye" Chuku is a Nigerian musicologist, pianist, and author. Inspired by his role model (Jermaine Griggs) who has become his mentor, what he started off as teaching musicians in his Aba-Nigeria neighborhood in April 2005 eventually morphed into an international career that has helped hundreds of thousands of musicians all around the world. Onye lives in Dubai and is currently the Head of Education at HearandPlay Music Group and the music consultant of the Gospel Music Training Center, all in California, USA.

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