Tritone and Augmented Intervals / Music Theory Lesson

Author: sleepfreaks

The Tritone and the Augmented Intervals

This time, we will take a break from chords and take a look at “tritone”
and the related “augmented” intervals.

The Thrilling yet Crucial Tritone

Lets give it a listen.

We’ve seen this interval before.
It has a particular sense of urgency and is a little difficult to listen to in repetition.
You may have heard that once upon a time, the tritone was known as “the devil’s interval”.

However, this tritone is an incredibly crucial sound when making music.

Lets take a look at this sound on notation and the piano roll.



Perhaps the name will give us some insight on this interval.

  • “Tri”tone
  • “Tri” meaning 3 from Latin/Greek roots

It seems this “3” plays a part.
That’s right. The distance between the 2 notes is 3 whole-steps.

Lets take a look at the F and B.


The opposite works the same way.


The New “Augmented” Interval

Now, here we are introduced to the new “augmented” interval.

The concept of this interval is fairly simple.

Extend a major or perfect interval further by a half-step to make an augmented interval.

While perfect intervals were signified with a “P”, major with “M”, minor with “m”, and diminished with “dim”,
an augmented interval is signified with an “A”.



The names of the intervals are as follows:

  • AU = Augmented Unison
  • A2nd = Augmented 2nd
  • A3rd = Augmented 3rd
  • A4th = Augmented 4th
  • A5th = Augmented 5th
  • A6th = Augmented 6th
  • A7th = Augmented 7th
  • AO = Augmented Octave

Did you realize that there’s 1 tritone hiding among these intervals?

That’s right, it’s the A4th interval.
With C as a root, it would be the interval of C to F#.


In addition, if thought of as a diminished interval, it can be “Dim5th”,
and the “F#” would be notated as a “G♭” instead.


The Importance of the Tritone

Last but not least, lets hear a sample that helps clarify why the tritone is important in music.

This is when the tritone moves to a certain sound.

It gives us this feeling similar to reaching a goal doesn’t it?
Like we have been freed of the tension.

We will be taking a look at the reason behind this in our next music theory article, so remember this sound!

Article Writer: Kazuma Itoh

講師 伊藤
After moving to the USA at 18 years of age with a scholarship from Berklee, he completed a 4 year study focused on song writing and arranging there.
Using this knowledge, he works across a variety of fields from pop music, film music, and more.