Music Theory Intervals That Actually Make Sense

Here we're going to work on basic music theory intervals. Ok, I didn’t actually realize until I started writing this, but apparently, I use them all the time without thinking about it. Whether it’s learning harmonies in my vocal lessons, working out new melodies, or tuning the strings on my instruments, intervals are everywhere, and you won’t be able to get around without them.


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What is an interval?

This is an easy question. An interval is just the distance between two notes. That’s it. The distance from A to G is an interval called a seventh. The distance from C to E is an interval called a third. The distance from F to B is an interval called a fourth. Get the idea?

There are actually two ways to play intervals: harmonic and melodic. Harmonic intervals are when you play the two notes at the same time, (like in a chord). Melodic intervals are when you play one note, then the other one, (like in a melody).

There are different types of sevenths, thirds, and fourths, but that’s all in another article.

Why do we need to know these?

Here’s why. Grab your favorite instrument and play any two notes. Seriously, right now, any two notes. You have just done one of three things. You either: 

  • played the same note twice
  • Played a note, then a lower note
  • Played a note, then a higher note

Unless you played the same note twice, you played an interval. Actually, I take that back: even if you played the same note twice you played an interval called a unison.

The point is that music is made of intervals, intervals, intervals everywhere! In order to get around in the world of musicians, you have to at least be familiar with the basics of these.

Ever heard the term parallel fifth or perfect fifth? How about the Diminished scale? What about an Augmented chord? Even the terms major and minor refer to the way we use music theory intervals.

-Tip: Practicing intervals is a great way to work on scales and intonation, and they make a great warm up exercise.


Naming Intervals with Major Scales

We name intervals by how far they are from the root note in a major scale. Here’s an example with a C Scale:

C D E F G A B C

R 2 3 4 5 6 7 R

If we go from the root to the third, that is an interval called a third. If we go from the root to the sixth, that is an interval called a sixth. From the root to the fourth is called... you got it: a fourth. That’s pretty much all there is to this basic interval stuff.

So if someone says “I’m going to sing a third above you,” they mean they are going to sing the harmony part that is the third scale degree above your note.


Bigger Than the Scale

By the way, even though major scales only have 7 notes, that doesn’t mean we only have seven music theory intervals. You can add them up. From one note to the next note with the same name (C -> C) is an interval called an octave. We can even keep going from there.

C D E F G A B C D 

This is an interval we call a ninth.

C D E F G A B C D E F G A

This is an interval we call a thirteenth, etc.

Anything bigger than an octave is called a compound interval. (Not really important, just in case you ever wanted to know.)


So I get it. These are important. How do I practice them?

Here are a couple of things you can do to get more familiar with these.

  1. Pick a key, any key, and run up and down that scale a couple of times. Now practice playing the root note (name of the key) and the 2nd note of that scale. Ex: C - D. Now do that with the 3rd note of that scale. Ex: C - E. Now do that with the 4th note of that scale. Ex: C - F. Seem easy? That’s because it is.
  2. If you did that on any instrument other than the piano, do it again on the piano. (Even if you don’t claim to be “a piano player”.) The piano is one of the easiest instruments to understand music theory on because the notes are all laid out in a straight line. It’s easy to see how the note relationships work and will increase your understanding of music theory intervals.
  3. Now do that same thing, but play all of the notes the interval spans. For instance, if you’re playing an interval of a 4th in the key of C, instead of just playing C - F, you should play C - D - E - F. You can also do this in combination with the other like this.

C, 

C - D, 

C - E, C - D - E, 

C - F, C - D - E - F, 

C - G, C - D - E - F - G, 

etc.


Notice!

We only measured intervals starting at the root note and going up. Two things here:

  1. You can also measure them going down. Just use the scale backwards.

    C B A G F E D C

    When we go down a fifth from C, we get F.
    Usually intervals are measured the other way, going up.

  2. You can also start on a different note in the scale and go up.

    Ex.
    C D E F G A B C
    From D to A is a fifth.

    I don’t worry about that. If I wanted to know what a fifth up from D is, I’d just use a D scale. Once you get more familiar with these, you won’t even think in terms of any scale, you’ll just know them automagically.

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