Musical intervals: visual guide for beginners

It is possible that on more than one occasion you have heard comments like: “If you study the notes of this stave, you will see an interval of diminished sixth.” If you did not understand what they meant, do not despair: in this guide you will know what the intervals are and how you can use them.

If you are a beginner, you should keep in mind that it is impossible to understand, for example, the chords, without first studying the intervals. It’s like trying to calculate without knowing the numbers and mathematical signs.

What is a musical interval?

Music as art draws on three significant elements: harmony, rhythm and melody. However, there are certain elements that are common. We refer, of course, to the intervals.

In the same way that elementary magnitudes (mass, time, etc.) are qualified according to their own measurements, music also uses certain resources to calculate their characteristics. For instance, one of the best known is the pulse, by which we can measure musical time. Similarly, there is a way to measure the relationship established between two musical notes: again, the interval.

When we talk about interval we mean the contrast of the pitch between two sounds. This concept contains the same to a single sound that lots of sounds at the same time (such as chords), and to those that are played continuously as melodies.

The numerical expression to represent an interval is usually a simple proportion. If we take the relationship established between two sounds located at a distance of exact fifth, it will always be 3 and half tones. But that will be discussed in greater depth later.

We could say then that an interval is formed when different sounds are played, and when they produce different frequencies.

How to measure musical intervals step by step

So far everything is clear. However, a question arises. How do we calculate the difference between pitch? Or, in other words, can an interval be measured?

The answer is yes: an interval can be measured. The most common way is to enumerate the tones and semitones that are among the pair of notes that make up this musical pause. The first thing to do to discover the key of the interval we want to measure is to determine which first note is played.

For example, if there are a couple of notes in a stave, and the first one is F and the other is B, the most logical thing is to affirm that we are in the F major range. In other words, starting from the most deeptoned note we will always find the key.

Next, we will see that other ways can also be used to name the intervals, and this is achieved by understanding the elements by which they are formed: tones and semitones.

Tone and semitone

When we talk about tone and semitone we refer to the regulatory distance that exists between two notes, always according to the model of the western scales. These have different ways of distributing. The halftone is the smallest distance established between two notes. On a guitar, for example, it is in the distance between a fret and the one that follows it (or also between an air string and the number one fret).

Semitones types and tone

There are two kinds of semitones:

Chromatic: The two notes that constitute the halftone are called the same.

Diatonic: The two notes that constitute the halftone have different names.

Now, the difference between both types is not sound, but in their writing. The sums of two semitones form a tone. If we take the C and D notes on a piano, both are distanced by a tone, while those of E and F only separate them by a semitone. As in the procedures of Western music the halftones separate the notes, we have that between the letters C and D then an intermediate note appears.

If you look at a piano keyboard, black keys are placed at the top, between two adjacent pieces. It is interesting to note that, for each note separated by a tone of the successive one, there is a black key that divides them.

Identifying the type of interval

Usually an interval is not designated according to the tones and semitones that compose it (although it can also be done), but a numerical arrangement is established, depending on the distance between the sounds. When we talk about notes we mean the seven that everyone knows: C- D- E -F -G -A -B, in contrast to the 12 semitones that coexist between them.

To number an interval, the total number of notes it comprises is counted (counting those that constitute that interval).

Classification of intervals

To classify an interval we must take into account the order in which each of them is cataloged. Therefore, the intervals can be: Major, Minor, Fair, Increased or Decreased.

An indication to consider: The intervals of 4th, 5th and 8th may be fair, diminished or increased. Only the 8th can be fair. The intervals of 2nd, 3rd, 6th and 7th may be higher or lower.

To understand it better, an interval of 4th will never be less, nor will one of 3rd. In addition, when we use the denominators “increased” or “decreased”, it is important to keep in mind that they can be used at any interval. That is why the increased intervals have a semitone more than their relative major interval. On the contrary, those that are diminished comprise a semitone less than their immediate minor interval.

Of course, there are other ways to catalog musical intervals.

A good illustration would be that, although we know how to read and write, we do not need to have absolute preparation in branches such as grammar to have a good spelling. In any case, we study basic principles such as the elements that make up a sentence, the lexeme, etc., always with the intention of improving our knowledge.

Similarly, working with interval theory helps us to understand the formation of chords without having to go deeper into more complicated concepts. If we are told that a chord has a fundamental, a fair 5th and a minor 7th, we know that we are faced with intervals.