In this blog post, we will be talking about everything you need to know about intervals in music.
Table Of Content
Definition Of Intervals In Music
In music, an interval is a measure of distance from one note to another. For example, in the illustration below, we would say that the interval between the pair of notes on the left is smaller than the interval formed by the pair of notes on the right
The standardized way of describing intervals would be to describe it in two parts:
Numeric description of the interval
Quality of the interval
Here are some examples:
Don't worry if you don't understand how we named the above intervals yet. That's exactly what we are going to cover in this blog post. To learn how to identify any given interval, let's use the following example interval:
To name any given interval, you would follow these steps:
How Do You Identify An Interval In Music
Step 1: Form The Major Scale From The Lower Pitched Note Of The Interval
To name an interval, we would first form the major scale from the lower pitched note in the given interval. In this case, the lower pitched note is B, and hence we would form a B major scale.
Step 2: Number The Scale Degrees Of The Major Scale
The next step would be to take that scale from step 1, and number the scale degrees
As you can see in the illustration above, our interval is some kind of 6th interval. As mentioned before, there are two parts to naming an interval:
Numeric description of the interval
Quality of the interval
Up till this point, we have identified the numeric description of the interval. The next step would be to determine the quality of the interval.
Step 3: Determine The Quality Of The Interval
There are five possible intervallic qualities, and they are:
Major
Minor
Perfect
Augmented
Diminished
Scenario 1: The Higher Pitched Note In The Interval Can Be Found As One Of The Scale Degrees Of The Major Scale
In order to determine the intervallic quality, we would compare the higher pitched note in the interval against the major scale formed from the lower pitched note in the interval. If the higher pitched note can be found in the major scale as one of its scale degrees, the naming of the interval would be as follows:
1st = Perfect Unison
2nd = Major 2nd
3rd = Major 3rd
4th = Perfect 4th
5th = Perfect 5th
6th = Major 6th
7th = Major 7th
8th = Perfect 8ve or Perfect 8th
Hence, in our example question, the higher pitched note is G#, which can be found in the B major scale as the 6th degree of the B major scale, hence the interval would be named a Major 6th.
Scenario 2: The Higher Pitched Note In The Interval Cannot Be Found As One Of The Scale Degrees Of The Major Scale
In our previous example, it was easy to determine the interval as the higher pitched note in the interval (G#) could be found as one of the scale degrees of the major scale formed from the lower pitched note in the interval. However, let's now try an example whereby the higher pitched note in the interval cannot be found as one of the scale degrees of the major scale. Take, for example, the interval between B and G
In this case, because the higher pitched note of the interval (G) is lower than the G# in the major scale by a semitone, this interval would no longer be named a 'major 6th', but it will be now named a 'minor 6th' instead.
Rule: If the higher pitched note of the interval is lower, by a semitone, than what would have originally been a major interval (2nd, 3rd, 6th, 7th intervals), then it would now be named a minor interval
Let us consider yet another example. Take, for example, the interval between B and Gb.
Notice how, in the above example, the higher pitched note in the interval, Gb, is lower, by two semitones, than the G# found major scale formed from the lower pitched note in the interval. Hence, it is no longer a major 6th, but would be named a 'diminished 6th' instead
Rule: If the higher pitched note of the interval is lower, by two semitones, than what would have originally been a major interval (2nd, 3rd, 6th, 7th intervals), then it would now be named a diminished interval
Now let us consider the interval between B and G𝄪 (G double sharp).
As the G𝄪 is higher than the G# in the major scale by one semitone, we would now call the interval an 'augmented 6th' instead of a major 6th
Rule: If the higher pitched note of the interval is higher, by one semitone, than what would have originally been a major interval (2nd, 3rd, 6th, 7th intervals), then it would now be named an augmented interval
Let us now consider a different example, say, the interval between B and F#
To recap, if the higher pitched note in the interval can be found as a scale degree in the major scale formed from the lower pitched note in the interval, the naming of the intervals will follow these rules:
1st = Perfect Unison
2nd = Major 2nd
3rd = Major 3rd
4th = Perfect 4th
5th = Perfect 5th
6th = Major 6th
7th = Major 7th
8th = Perfect 8ve or Perfect 8th
Hence, the interval between B and F# will be described as a perfect 5th.
However, what if the F# were an F natural?
In the above scenario, we would apply the following rule:
Rule: If the higher pitched note of the interval is lower, by one semitone, than what would have originally been a perfect interval (1st, 4th, 5th and 8ve intervals), then it would now be named a diminished interval
Let us now consider the interval between B and F𝄪 (F double sharp)
Rule: If the higher pitched note of the interval is higher, by one semitone, than what would have originally been a perfect interval (1st, 4th, 5th and 8ve intervals), then it would now be named an augmented interval
Intervals Summary
Now, let us summarize all the rules we have covered thus far:
Construct the major scale from the lower pitched note in the interval, and check whether the higher pitched note can be found as a scale degree in that constructed major scale. If yes, the naming of the intervals would follow these rules:
1st = Perfect Unison
2nd = Major 2nd
3rd = Major 3rd
4th = Perfect 4th
5th = Perfect 5th
6th = Major 6th
7th = Major 7th
8th = Perfect 8ve or Perfect 8th
If the higher pitched note of the interval differs from the notes found in the constructed major scale, then the naming would follow these rules
A raised major interval (2nd, 3rd, 6th, 7th), by one semitone, would be named an augmented interval
A lowered major interval (2nd, 3rd, 6th, 7th), by one semitone, would be named a minor interval
A lowered major interval (2nd, 3rd, 6th, 7th), by two semitones, would be named a diminished interval
A raised perfect interval (1st, 4th, 5th, 8ve), by one semitones, would be named an augmented interval
A lowered perfect interval (1st, 4th, 5th, 8ve), by one semitones, would be named a diminished interval