• Consonant Intervals: The Building Blocks Of Major and Minor Triads (+ Bonus 111-pg PDF Quick Guide)

    in Chords & Progressions,Piano,Theory

    In this lesson, we’ll explore the ins and outs of consonant intervals.

    Attention: There is a free 111-pg Quick Guide associated with this lesson

    An “interval” is the distance between two points, events, or ends. There is an emphasis on “two” that cannot be understated. In terms of intervals, we’re thinking of an A and a B.




    The A->B illustration above should give you an idea of what the word interval means. Musically, intervals describe the distance between TWO pitches. One is considered the A and another the B. These note combinations below are all intervals:

    These intervals may be played/heard simultaneously (together) or successively (separately) and there are two classes of intervals in terms of the relationship between the notes involved.

    Harmonic Intervals. When played simultaneously, intervals are said to be harmonic.

    Melodic Intervals. When intervals are played successively, they are called melodic intervals.

    Intervals may sound pleasant or unpleasant.Intervals that are pleasant are said to be consonant while unpleasant intervals are said to be dissonant. The goal of this article is to present you with ideas on consonant intervals that you will find relevant to the construction of Major and minor triads on the keyboard.

    Intervals are related to chords. Chords involve three or more notes. We can say that in chords we have:


    A——>B——>C——>D (etc)



    Consonant intervals in western music are intervals that sound agreeable, as opposed to dissonant intervals, which we are going cover in another article.

    Consonant intervals include Major and minor thirds, Major and minor sixths and the perfect fifth.

    • Major Thirds
    • Minor Thirds
    • Major Sixths
    • Minor Sixths
    • Perfect Fifths

    **Sometimes, the Perfect Fourth is added to the list. However, it is generally considered a dissonant interval.


    It’s important to say at this point that thirds and sixths are related. This will help us get more organized as we progress. Thirds and sixths have an inverse relationship. Inverting a third will yield a sixth and vice versa. For example, C-E (a third):
    C-E, Major Third on C

    …when inverted, yields E-C:
    E-C Minor Sixth on E

    C-E is a third while E-C is a sixth.
    C-E, Major Third on C
    C-E in the illustration above, spans three diatonic degrees – C, D and E, while E-C below spans six diatonic degrees E-F-G-A-B and C.
    E-C Minor Sixth on E

    An understanding of inversions and the intervallic relationship between thirds and sixths, will prove helpful as we progress. We can associate thirds with sixths henceforth because every third is an inverted sixth and every sixth is an inverted third.

    One more thing…

    Inversion of intervals changes its quality – perfect intervals are an exception to this. After inversion, a major quality becomes a minor quality and a minor quality becomes a major quality.

    Put this together and you’ll discover that inversion changes two intervallic factors. Inversion changes the Quality and Quantity of intervals.

    The interval below is a Major Third:
    C-E, Major Third on C

    Here’s a proper way to understand the quality and quantity of the interval above (and any other interval).

    Major Third – Major refers to the quality of the interval and the harmonic environment associated with it.

    Major Third – Third refers to its quantity, which is the size of the interval (determined by the number of scale tones encompassed).

    In inversion, there are two simple processes:

    Inversion of quality and inversion of quantity. Most times, for inversion to take place, there must be a change of quality and quantity. Words like MAJOR describe quality while words like THIRD describe quantity.

    Alright, let’s put our knowledge to work by inverting a few intervals. Good news is that we don’t need a keyboard for this.

    Example #1 – Major Third

    Inversion of Quality – Major becomes Minor

    Inversion of Quantity – Third becomes Sixth

    Therefore, a Major Third becomes a Minor Sixth after inversion.

    Example #2 – Minor Sixth

    Inversion of Quality – Minor becomes Major

    Inversion of Quantity – Sixth becomes Third

    Therefore, a Minor Sixth becomes a Major Third after inversion.

    Example #3 – Minor Third

    Inversion of Quality – Minor becomes Major

    Inversion of Quantity – Third becomes Sixth

    Therefore, a Minor Third becomes a Major Sixth after inversion.

    Example #4 – Major Sixth

    Inversion of Quality – Major becomes Minor

    Inversion of Quantity – Sixth becomes Third

    Therefore, a Major Sixth becomes a Minor Third after inversion.

    Attention: There is a free 111-pg Quick Guide associated with this lesson


    In European art music (aka – “classical music”), thirds (and sixths [its inversion]) are used in harmony. When we are talking about harmony, it refers to the relationship between notes that are heard together.

    These note combinations don’t just happen – No! A class of harmony is used and the class of harmony used in this case is the tertian harmony.

    In this class of harmony, notes can be harmonized using these consonant intervals – thirds (and sixths [its inversion]).

    Oops! Looks like we’ve forgotten the Perfect fifth.


    This is another consonant interval. In classical music, it is called the perfect consonance. This is because, it contains two important scale-degree notes – the tonic and the dominant. Tonic and Dominant are technical names used to refer to the first and fifth scale degrees.

    In the Major Scale of C,
    C major scale C D E F G A B

    C is the tonic while,

    G is the dominant

    The perfect fifth is the relationship in pitch between the tonic and the dominant.

    When a perfect fifth is inverted, its quality remains the same. Perfect intervals remain perfect even after inversion.

    The same way we know states and their respective capital cities, every musician must be familiar with the tonic and dominant of all the keys (24 of them [12 Major + 12 Minor keys]). So the relationship between the tonic and the dominant yields a perfect fifth in all the keys.


    Triads contain three elements – that’s why they are called triads. These three elements are

    • The Root
    • The Third
    • The Fifth

    From the intervallic elements of the triad, we can see that it contains a third and a fifth. This means that consonant intervals are the building blocks of triads. It is with thirds and fifths that triads are built and most thirds and fifths are consonant.

    There are diminished and augmented thirds and fiftha, and they are dissonant intervals. So we can categorize triads into consonant and dissonant triads.

    Major and minor triads are formed from consonant intervals unlike diminished and augmented triads that are formed from dissonant intervals. Triads formed from consonant intervals are called concord.

    Major and minor triads share one thing in common – they are concords. The intervals that make them up (the quality of third and fifth) are consonant. Below are the qualities of third and fifth that are consonant:

    • Major 3rd
    • Minor 3rd
    • Perfect 5th

    There are two qualities of thirds and one quality of fifth and that implies that Major and minor triads differ in their quality of thirds and have a perfect fifth in common.

    The Major triad will have a Major third and the minor triad will have a minor third. This is a little bit different in diminished and augmented triads which we’ll explore while studying dissonant intervals.


    Considering that Major and minor triads have the same quality of fifth, that means that the difference between a Major and a minor triad is in the quality of third used. Knowledge of all the Major and minor thirds on the piano is indispensable, invaluable and priceless.

    Now that you’re done with this post, here is a FREE Quick Guide on Consonant Intervals that is specially packaged for you.

    • A Complete Guide on the mastery of Consonant Intervals in ALL the keys.
    • Five Chapters with graphical illustrations using virtual keyboard diagrams.
    • Over 100 Pages of step-by-step information.
    • 50 Exercises and Answers

    You are going to find it easy to use because for the first time ever, we’re organizing intervals according to their color patterns.

    Simply enter your first name and e-mail and the guide will be immediately available on the next page.

    It’s priceless, yet absolutely FREE.

    Until next time.

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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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