THEORY OF MUSIC (II)
Tutorial about theory of music: basic knowledge of chords and arpeggios.
Chords
Chords are two or more notes being played simultaneously. Their importance in the musical process lies in that they help to fill the sound, set a mood and, sometimes, keep the rhythm. In the previous chapter we have seen the method of numbering the notes of the chromatic scale with roman numerals, for the purpose of creating a recipe for building scales. In this chapter we will use those numerals to create recipes for building chords. We can take any note, for example C, and look at the chromatic scale in numeral form:
To create a C major chord we would play C-E-G or the numerals I-III-V. So for creating a major chord the recipe indicates the first, the third and the fifth note of the C major scale. The following pictures show this chord represented in music notation and as played on a piano keyboard.
The following are some common chord recipes:
When playing chords the order of notes can be changed and hence there are different ways of playing the same chord. These variations are called inversions and each of them will sound slightly different. For example, the C major chord could be played as I-III-V, III-V-I or V-III-I. Besides, it is not mandatory to play all of the notes of a chord; often fewer notes will be all that we need.
Chords are useful in different ways depending on the context. When played rhythmically, as when strumming a guitar, they can help in keeping the beat or playing counter rhythms. When playing an organ or a string section chords are used to fill the sound, adding depth and mood. Different types of chords are supposed to transmit different moods; for example, minor chords would feel sad or mysterious, diminished chords would be suspensful, sixth chords would be airy, seventh chords would be happy and so on...
A certain way of playing the notes of a chord is the arpeggio, in which instead of playing notes simultaneously these are played in rapid succession. Whoever is familiarized with synthesizers has surely seen an electronic arpeggiator, a device which automatically creates arpeggios of the notes played, usually in a repeating way. In the following picture we can see the arpeggiator of a classic virtual synthesizer and its associated controls. The arpeggiator can be enabled or disabled and set to play arpeggios either downward or upward; its speed, which is measured in beats per measure, indicates how many notes will be played on each measure; and its gate, which can be enabled or disabled, allows to mute individual beats to create different rhythmic patterns.
