The Differences Between The Minor Third And Augmented Second Intervals

This lesson is for anyone who wants to know the differences between the minor third and augmented second intervals.

I once believed that the minor third and augmented second intervals are identical, I was of that opinion because both intervals had the same number of half steps. However, as I learned more about intervals, I got to know important differences between both intervals.

If you give me the next five minutes or so, I’ll be showing you the differences between the minor third and augmented third intervals.

An Overview Of Intervals

An interval according to Jermaine Griggs “…is the relationship between two notes that are played/heard [together or separately] in terms of the distance between them.”

Although the above definition of intervals is quite comprehensive, permit me to break it down to smaller and digestible proportions.

“…the relationship between two notes…”

The use of the term interval in music has to do with “the relationship” between two notes. The relationship between notes of an interval here has to do with a scale relationship. The interval between C and E:

…is a third because it encompasses three adjacent notes – C, D, and E:

…however, two notes are treated in relationship with the C major scale:

…and are therefore considered to be a major third.

The use of the term major here to qualify the interval between C and E:

…is based on their relationship founded in the key of C major.

“Here’s a breakdown of the scale relationship between three known intervals…”

C and Ab:

…is a minor sixth interval. The C minor scale:

…shows the scale relationship between both notes. Take note that C and Ab:

…are the first and sixth tones of the C minor scale.

D and F#:

…is a major third interval. The D major scale:

…shows the scale relationship between both notes. Take note that D and F#:

…are the first and third tones of the D major scale.

F# and B:

…is a perfect fourth. The F# major scale:

…shows the scale relationship between both notes. Take note that F# and B:

…are the first and fourth tones of the F# major scale.

“In a nutshell…”

Any set of two notes on the piano can form an interval; provided that there’s a scale relationship between those notes.

Also note that an interval doesn’t have as much as three notes because the relationship between three or more notes produces chords.

…played/heard together or separately…”

An interval can be played or heard together or separately. Consequently, there are two forms of intervals – melodic and harmonic intervals.

Melodic intervals are intervals that are formed when two notes are played or heard separately while harmonic intervals are formed when two notes are played or heard together.

“…the distance between them…”

Intervals can be used to describe the distance between notes on the piano. Although an octave:

…contains 12 half steps:

…it is seen as a distance of an eighth (aka – “octave”.) An interval of a sixth would encompass six degrees of any given scale. For example, the interval from C to A:

…is a sixth because it encompasses six tones of the C major scale:

…from C to A:

Enharmonic Relationship Between Intervals

It’s possible for two different intervals to have the same number of half steps. Intervals that differ in size and quality, but have exactly the same number of half steps are known as enharmonic intervals.

C-F#:

…and C-Gb:

…are an example of enharmonic intervals that we’ve covered in a previous lesson. Both of them are different in size and quality.

“In terms of size…”

C and F#:

…is a fourth while C and Gb:

…is a fifth.

Attention: C to F# is considered a fourth because from C to F are four letter names (C, D, E, and F) while C to Gb is considered a fifth because from C to G encompasses five letter names (C, D, E, F, and G.)

“In terms of quality…”

C and F#:

…is an augmented interval because in the key of C:

…the interval C and F#:

…is bigger than C and F:

…(which is a perfect fourth interval) by a half step.

Conversely, C and Gb:

…is a diminished interval because in the key of C:

…the interval C and Gb:

…is smaller than C and G:

…(which is a perfect fifth interval) by a half step.

Although C-F# (an augmented fourth interval):

…and C-Gb (a diminished fifth interval):

…differ in size and quality, however, both intervals have enharmonic relationship. This explains why they sound alike when they are played or heard.

The C augmented fourth:

…and C diminished fifth:

…intervals are commonly known as the tritone and each encompasses six half steps.

The Augmented Second vs Minor Third Intervals

There are other enharmonic intervals on the piano, however, we’ll be looking at the augmented second and minor third intervals and exploring the differences between them.

“Here’s a few things you have to note about these intervals before we proceed…”

The augmented second interval is formed by raising the major second interval by a half step.

Always remember that the major second interval is formed by the relationship between the first and second tones of the major scale.

Raising C-D:

…(a major second interval) by a half step produces C-D#:

…an augmented second interval.

The minor third interval is formed by lowering the major third interval by a half step.

Note that the major third interval is formed by the relationship between the first and third tones of the major scale.

Lowering C-E:

…(a major third interval) by a half step produces C-Eb:

…a minor third interval.

Submission: At this point, I shouldn’t be saying that C-D#:

…and C-Eb:

…are different intervals in terms of size and quality because from what we covered earlier, they differ from each other.

“Let’s go ahead and explore the differences between the augmented second and minor third intervals in terms of chord formation…”

Attention: All chords, irrespective of size, class, etc., can be broken down into intervals. That’s why Jermaine Griggs refers to intervals as “…the building blocks of chords.”

Beyond that, it is very important for you to note that the type of interval that a chord is made up of, determines the overall outcome of the chord. For example, chords that contain the diminished fifth interval, are usually referred to as diminished chords.

Let’s look at the differences between the augmented second and minor third intervals when they are used in chord formation.

Difference #1 – “The Augmented Second Interval Is Dissonant While The Minor Third Interval Is Consonant”

All augmented [and diminished] intervals sound harsh and have a degree of unpleasantness when heard and the augmented second is no exception.

The minor third interval sounds agreeable and is used in chord formation while the augmented second interval is not commonly used in chord formation because it is unpleasant (aka – “dissonant”.)

This explains why the C minor triad:

…has the C minor third interval:

…as one of the intervals that makes it up (aka -“intervallic component”), and not the C augmented second interval:

“Take note that…”

Using the C augmented second interval:

…as an intervallic component of the C minor triad:

…is forbidden.

Difference #2 – “In Tertian Relationship”

Following the traditional principles of chord formation, notes are stacked in third intervals and this produces a tertian harmony. In the tertian relationship of the notes of a chord, the root is followed by the third and not the second.

Notwithstanding that the augmented second and minor third intervals have an enharmonic relationship, they differ in size – the former is a second while the latter is a third.

The minor third interval fits into the tertian relationship of notes during chord formation while the augmented second interval doesn’t fit in.

“Suffice It To Say That…”

In the formation of extended dominant chords, the augmented ninth interval (aka – “the sharp nine”) is used as an extension.

The difference between the augmented ninth and the augmented second intervals is that the former is a compound interval and the latter is a simple interval. The C augmented ninth interval:

…and the C augmented second interval:

…are spelled as C-D#.

Final Words

I’m glad that you’ve seen that the augmented second and minor third intervals have clear differences and distinct harmonic traits.

This is the end of today’s lesson and lest I forget, thanks for your time.

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Chuku Onyemachi

Head of Education at HearandPlay Music Group

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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