Perfect Intervals: The Quality of Your Musical Life

Before you continue with this lesson on musical intervals, be sure you have read lesson one. At the end of that lesson, I gave you an assignment, so here’s a little quiz. Identify the numerical value of the following intervals, saying each one aloud as quickly as you can.

Click here for the answers

How did you do? I’m not saying you should have been able to name all those intervals in 10 seconds or less. What I am saying is that you should be able to look at an interval and name its numerical value without having to count the scale steps. As we move on to interval quality, I’m going to assume that you are able to name an interval’s numerical value somewhat fluently. If you need to, go over the previous lesson again, and keep practicing.

Interval Quality

Learning how to recognize interval quality can get complicated, and there are several different methods for teaching it. There will be three more lessons on intervals (including this one), where I will introduce you to different ways of learning interval quality. If you’re having a hard time understanding it, keep plowing through these lessons, and I think it will begin to make sense to you. We all learn differently; there is no single method that is best for everyone. Again, however, let me emphasize the importance of being fluent with the numerical value of the intervals, because that’s the easy part.

The five possible qualities for musical intervals are listed below, along with their abbreviations, and the numerical values to which they apply. The meaning of the quality names will become apparent as we move forward:

Perfect intervals apply only to unisons, 4^ths, 5^ths, and octaves. Major and minor intervals apply only to 2^nds, 3^rds, 6^ths, and 7^ths. So we’ll divide learning interval qualities into two groups: group one, the Perfect Intervals and group two, the Major/Minor Intervals.

Group One: The Perfect Intervals

Method One

The Perfect Intervals include unisons, 4^ths, 5^ths, and octaves. You will never see, for example, a major 4^th, or a minor 5^th, etc. (The reason for this will become apparent later.)

Perfect unisons (P1) and octaves (P8) always have the same accidental:

Perfect 4^ths and 5^ths have the same accidental with one exception. Below are various examples of perfect 4^ths and perfect 5^ths, but notice that none of them have both a B and an F:

Now look at the next example of perfect 4^ths and 5^ths. All of them have a B and an F:

Let’s summarize the exception:

Perfect 4^ths and 5^ths have the same accidental except when the interval has a B and an F, in which case:

• B is always one accidental lower than the F

Do you notice that when the F is sharp, the B is natural, and when the F is natural, the B is flat? That’s what I mean by “one accidental lower.”

If you can remember this exception, learning the perfect intervals using this method is fairly easy. Just remember that perfect intervals have the same accidental, unless the interval has a B and an F.

Method Two

You can learn perfect intervals by relating them to a major scale. This method is good if you are fluent with your major scales. (I’m skipping over the perfect unisons and octaves because they’re obvious.) Here’s how it works:The two tetrachords (WS-WS-HS) of a major scale span a perfect 4^th. In other words, up to , and up to are perfect 4^ths. up to of a major scale is a perfect 5^th. There are other perfect intervals in the major scale, but these are the easiest to remember.

Method Three

You can learn all of the intervals simply by memorizing the number of half steps there are between the two notes. This method might seem tedious at first, but when the intervals start getting more complex, counting half steps is a good checkpoint. We’ll start with the perfect intervals. Again, you don’t have to memorize the perfect unison and octave since they’re obvious:

• P1 = 0 half steps
• P4 = 5 half steps
• P5 = 7 half steps
• P8 = 12 half steps

There are a few caveats with this method, so I’ll talk more about it, including giving you a complete chart, once we’ve gotten through all of the qualities.

That completes the perfect intervals. Remember, only unisons, octaves, 4^ths, and 5^ths can be perfect. Next, we’ll move on to the Major/Minor Intervals.

Go to Intervals Lesson 3

A Word about Interval Ear Training

I have considered developing online ear training exercises so readers could practice learning the sounds of the intervals. Years ago, I developed an ear training program that my students used at Vanguard University. Since I’m not much of a programmer anymore, and because there are already so many great programs out there, I’ve decided against going that route. However, I will be discussing interval sounds quite a bit, and giving you tips on how to learn them. A program that I highly recommend, and have used for years is Practica Musica (availalbe for Windows and Mac OS). I believe it is the best ear training software on the market, and you can purchase it here: