What are augmented, diminished and perfect intervals?

If you have read the article about degrees, you saw that we mentioned only 7 notes in western music (C, D, E, F, G, A, B). But if we wanted to use a reference for other notes too? (C#, D#, F#, G#, A#)? For this there is a more embracing definition, as we will see now:

The first note is represented for the first degree, as we already saw. Let’s use like example the first degree of the C note.

In this case, the D note is the major 2nd. The note C# (or Db), in this case, is the minor 2nd. This nomenclature (“major” and “minor”) exists to indicate if the interval (distance between two notes) is short or long. Major intervals are long and minors are short. You can see that in the previous example, the “major second” represented the interval of one tone (because D is a tone above C), and the “minor second” represented the interval of half tone (Db is half tone above C). Therefore, these names were given just for distance identification between notes. Expanding the concept to all notes, starting with C, we have this:

C —> first degree major (perfect unison)
C# —> minor 2nd
D —> major 2nd
D#—> minor 3rd
E —> major 3rd
F —> perfect 4th
F#—> augmented 4th or diminished 5th
G —> perfect fifth
G#—> augmented fifth or minor sixth
A —> major sixth
A#—> minor seventh
B —> major seventh

Probably you have already asked yourself why do these names “augmented”, “perfect” and “diminished” exist. Well, you have to know that it is just a definition, and this is the “language” that you will find in any book about music or song books. The logic is the same as we saw for the names “major” and “minor”. The name “augmented” indicates an interval longer and “diminished” indicates an interval shorter. “Perfect” is in the middle of these two.

But we can not simply use the names “major” and “minor” to all the notes instead of using “diminished”, “augmented” or “perfect”? Yes, we could. So, why do other names exist? In the advanced topics you will understand why this becomes really useful. For now, just memorize these nomenclatures and what they represent. As you saw, there is no mystery, it is just given names to specific degrees.

Let’s now exercise this nomenclature starting from other notes besides C:


From the seventh degree, notes start to repeat themselves, because the 8th degree is the same as the 1st.

Following this logic:
– 9th degree is the same as the 2nd degree.
– 11th degree is the same as the 4th degree.
– 13th degree is the same as the 6th degree.

You can be asking yourself: if there is no need to talk about degrees after the seventh, because they repeat themselves, why don’t they use the notation 9th, 11th and 13th?? Well, some musicians prefer to use these degrees to make clear which octave must be used. For example: If it is written the chord symbol Cm6, probably you will create the chord of Cm and take the closest 6th degree to create Cm6. Now, writing Cm13, you would know that you have to use the 6th degree one octave above and not the closest 6th degree. The only difference is between this two chords is the sonority lightly distinct due to the octave used to 6th degree (in the next topics we will talk about everything you need to know about chords and symbols. Don’t worry if you didn’t understand this example).

And about the 9th extension, it is almost always one octave above, for this is used in the place of the 2nd. But this depends on the personal taste of each musician.

It is important for you to know details like these to not be in doubt about these nomenclatures.

Very good, let’s talk now about the practical use of all these notations that we saw!

Applying the concept of augmented, diminished and perfect intervals

We can refer ourselves to any note if we want to take as base some reference note. In the same way as we did with the article about degrees. We will take here the same principle of the previous article because we are complementing the subject; however, before we worked in C scale, saying just 3rd degree, 6th degree, etc, we weren’t specifying if the degree was major, minor, perfect, diminished or augmented. For this, it was important to say that degrees would be like the major scale format. Now it will be not necessary to link to a scale, because we will specify each degree separately. You have bellow some examples (exercises):

– Minor third degree of C: D#
– minor seventh degree of G: F
– minor second degree of D: D#
– augmented fifth of C: G#
– perfect fourth (or fourth degree) of A: D
– diminished fifth of B: F

You can check these answers with the table we showed before.

Observation: for example, we are only talking about notes, not chords! The names “augmented” and “diminished”, as well as the names “major” and “minor” also appear in chords, bur this is another approach! Try to not mix the things, we are here talking about notes and their isolated nomenclature. When the subject is chords, nomenclature has another purpose, For this is important this distinction. Keep this in mind.

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