Grade 5 Theory – Intervals An interval contains two pieces of information, a quality and a

quantity. For example: a Perfect Fifth, the first term describes how the interval sounds, the second refers to the distance between the two notes.

Quantity

The quantity is easy to work out, as you simply count how many notes that span the distance between the interval including the two constituent notes as well. For example C-E is a third, because it spans and includes 3 note: C, D, and E. Here are all the intervals up to an octave:

Note that a “1st” and an “8th” are never called such, but ‘Unison’ or ‘Octave’.

If an interval is more than an octave it is called a compound interval, like so:

Give the quantity of these intervals:

Quality As already mentioned, intervals also have a quality, which describes

how the interval sounds. Here are the qualitative terms for the intervals in a major scale, which you should learn.

Perfect intervals are called perfect because they sound the most pure and consonant. In the major scale these are the unison and octave (because they are the same note they sound very consonant) and the fourth and fifth. (all the ones that start with a ‘f’ if this helps!: Perfect intervals are the fourth and fifth.)

Working out the quality of an interval1. Imagine the lowest note as the tonic of a major scale.

© Philip Robinson 2012

2. If the other note is within that scale then it will be major or perfect according to the rules of the major scale.

3. If not then the distance will either be one or two semitones bigger or smaller than the major scale norm

a. Perfect intervals: if they are increased by a semitone they become augmented, if decreased by a semitone they become diminished.

b. Major intervals: if they are increased by a semitone they also become augmented, if decreased by a semitone they become minor.

i. A major interval can also be reduced by two semitones, in which case it becomes diminished.

Here is this process in a diagram:

Now work out these intervals:

© Philip Robinson 2012