Outro

Now you've gotten to know the entire cast of interval characters that do the heavy lifting for all of Western music. Hopefully you've made some progress finding them on the fretboard, and begun to put them to work in your own musical practice.

Before we move on, there are a few more things worth knowing about intervals, because they'll cross our paths eventually.

Simple and compound intervals

These lessons have dealt almost entirely with the 12 simple intervals in Western music--intervals of an octave or less.

But if you like playing more complex extended chords, you'll find that they often use intervals greater than an octave. These are called compound intervals. The good news is that there's not much more to learn about them, beyond understanding their names. For most purposes, compound intervals can be thought of as identical to the simple intervals an octave lower. The differences tend to be more theoretical than practical, especially on guitar where we have to take a lot of liberties with chord inversions and voicings just to fit everything into a playable grip.

But it can be very helpful to understand the names of compound intervals. As a practical matter, we can just memorize these translations:

• A ninth behaves just like a second.
• An eleventh behaves just like a fourth.
• A thirteenth behaves just like a sixth.

It's technically possible to use other compound intervals, but it's not common, and I think you can figure out the formula if you need to. (Hint: subtract 7.)

Augmented and diminished intervals

In the context of interval names, the term augmented means to raise an interval by a half step. For example, an augmented fourth (or #4) is a half step higher than a perfect fourth.

The term diminished means to lower an interval by a half step. A diminished fifth (or ♭5) means a half-step lower than a perfect fifth.

These terms are mostly used either when referring to perfect intervals (since lowering them by a half step can't be called a minor interval), or to describe raising or lowering a specific interval in a specific context.

Enharmonic intervals

You may have noticed that a diminished fifth and an augmented fourth and a tritone all refer to the same interval. This is similar to the situation in which we might refer to a G# in one key and an A♭ in another. When two different intervals or two different notes describe the same pitch class like this, they are called enharmonic.

It's actually useful to have different names for the same interval in this way, because it lets us name it the way we are thinking of it. In the context of a tritone, we're typically thinking of a ♭5. But in the context of the IV chord (or the Lydian mode), the fourth is raised a half step beyond where it would normally be for a major chord, so it's easier to think of it as a #4.

Enharmonic interval names also allow us to write the intervals for a diatonic scale or mode using exactly one of every interval number, with a different combination of sharps or flats, instead of having, for example, both a ♭5 and a 5 in the same scale.

Coda

And now we've reached the end of these interval lessons, as much as we can say our studies ever end. It will take some time to fully internalize them, but we're in no hurry. You can return to these lessons and exercises any time you need to refresh your memory. Gradually the intervals we've gotten to know will take up residence in the very structure of our brains, and they will help us in our guitar playing and study for the rest of our lives.