There are two different types of interval and these are harmonic and melodic. So what exactly is the difference between these two types of interval?
When labelling an interval there are two distinct steps you need to go through.
1. The distance of the interval - between the two notes.
2. The intervals quality - what descriptive word do we use for the interval?
Let's firstly visit how we work out what the distance in an interval is.
Take a look at this melodic interval. We have the notes C and E, how do we work out the distance between these two notes correctly?
Below we have a harmonic interval. What is the distance between the notes G and D?
It really is as simple as that. Always make sure that you start on the bottom or lowest note of your interval and count up in that scale including the starting note. It is important to note that even if the interval were to be written the other way around, with the higher of the two notes first, you would still start counting the interval from the lower note.
Before embarking on the rest of this blog post make sure that you know and understand exactly what a semitone and tone (whole steps and half steps) are as this will greatly help you when working out your intervals. Let's explore these now.
A semitone is the smallest interval you can have in western music (usually!). A semitone can also be referred to as half step.
A semitone is the note either above or below the original note. The easiest way to represent this is by looking at a piano keyboard. Highlighted is the note C, a semitone above this is C sharp or D flat and a semitone below is B natural or C flat.
A tone is made up of two semitones. A tone is also sometimes referred to as a whole step, it is also labelled as a major second but more on this later. The easiest way to show this is by looking at a piano.
There are five different interval qualities:
It most certainly is and therefore, this will be labelled a Major sixth.
An interval can be labelled major, if the top note of the interval is in the lower note of the interval.
You can also check that you have labelled your interval correctly by counting the semitones/half steps, if you feel comfortable with this.
A major second will always be three semitones including the starting note
A major third will always be five semitones including the starting note
A major sixth will always be ten semitones including the starting note
A major seventh will always be twelve semitones including the starting note
Take a look at the two notes below, we have a C and an E flat.
Alternatively, if you are confident with your minor scales then you can ask yourself if the top note is in the lower note of your minor scale. For example, let's write out the C minor scale
You can also check that you have labelled your interval correctly by counting the semitones/half steps, if you feel comfortable with this. The minor interval always has the distance of 4 semitones.
The intervals of a second, third, sixth and seventh can all be considered major or minor.
However, the intervals of a fourth, fifth and octave can only be considered Perfect. You will never use the descriptive words major or minor with the intervals of a fourth, fifth and octave.
Take a look at the scales below, notice how the 4th, 5th and 8ve notes are exactly the same.
If you have the interval of a 4th, 5th or 8ve and the note is in the major or minor scale of the lower note then each of these will be labelled perfect fourth, perfect fifth and perfect octave.
Make sure when working out your intervals you know whether you are looking at major/minor intervals or perfect intervals.
You can also check these intervals by looking at the number of semitones.
A perfect fourth has the distance of 6 semitones.
A perfect fifth has the distance of 8 semitones.
A perfect octave has the distance of 13 semitones.
Now let's look at augmented and diminished intervals:
In this section we will look at augmented intervals. An augmented interval is one semitone/half step larger than a major interval or a perfect interval.
Take a look at the augmented interval below. We have the notes G - C#, the distance between these notes is a fourth. Remember a fourth is considered a perfect interval if the top note is in the scale of the lower note. However, is C sharp in the G major scale?
If the top note had been a C natural this interval would have been a perfect fourth.
Take a look at the piano below and you can see why C sharp is one semitone larger than C natural and therefore why this is the interval of an augmented fourth.
Take a look at the diminished interval below. We have a C natural and a G flat. The distance between these two notes is a fifth. A fifth is considered a perfect interval if the top note is in the major or minor scale of the lower note. However, is G flat in the C major scale?
If the top note had been G natural then this would have been a perfect fifth.
Take a look at the piano below as you can see why G flat is one semitone lower than G natural and therefore why this interval becomes a diminished interval.
A compound interval is where the two notes in the interval are larger than an octave, remember an octave is eight notes. An interval larger than an octave would then venture into 9th, 10th, 11th etc. If you would like to know more about this then make sure to check out this blog post.