B3 | Harmony notes

Harmony notes leading to two-part homophony

We discussed the intervals between the notes of the scale in units A1 and B1.
This time, we’ll be discussing the intervals between notes that are played against each other
These are called harmonic intervals.
A harmonic interval can be measured by counting from the lower of the two notes staring on« 1 ».

a. State how many half-tones there are between the following intervals:

Fig. 1

2^nd	3^rd	4^th	5^th	6^th	7^th	8^th
Major	Major	Perfect	Perfect	Major	Major	Perfect

b. Describe the following intervals. The key is B^♭ major.

Fig. 2

Describing Intervals

There are two types of harmonic interval:

Consonant – a pleasant sound/pleasing to the ear
Dissonant – a harsh sound to the ear

The intervals of the 3^rd, 6^th and 8^th are consonant
The intervals of the 2^nd and 7^th are dissonant
The intervals of the 4^th and 5^th are open.

In a major scale the intervals of the 3^rd, 6^th and 7^th are called major.

In a minor scale the intervals of the 3^rd, 6^th and 7^th are called minor.

Traditionally, composers would avoid parallel intervals of the 4^th, 5^th and 8^th. The intervals of the 3^rd and 6^th are acceptable – look at figure 3 below. Therefore when composing in the style of composers from the Baroque and Classical periods, you shouldn’t have, for example, two intervals of a 4^th between the same parts. Look at the example below

Fig. 3

Avoiding parallel intervals

Also, there is a melodic leap of an augmented 4th in the soprano part in version A. Notice how version B is smoother and avoids parallel intervals.

Here is the opening of Mozart’s concerto for clarinet arranged for piano. Notice that the composer is using a series of consonant intervals in the upper part.

Fig. 4

Exercises

B3 Exercises

Composition task

B3 Composition task