Chords and Scales
A simple piece of tonal music in the key of, for example, C major will mostly use triads constructed from the diatonic scale of that key.
The example below shows the seven different root position triads that can be constructed from a diatonic scale of C major. These are the only consonant triads available other than their various inversions. The below are a mixture of major (I, IV and V), minor (ii, iii and vi) and diminished (vii). As discussed on the triads page, in most tonal styles, diminished triads are considered to be unstable and in some styles, minor triads are thought of as less stable than major ones.
[Not sure about the chord labels? Look in the chord identification section of the ToolKIT linked to at bottom of this page]
The major triads of I, IV and V are particularly important for establishing the key and mode (i.e. major/minor) of a passage of tonal music:
- most obviously, I, IV and V are major triads and their use emphasises the major sound (compare with the minor)
- a melody based on chord I (see the section on harmonisation in the introduction) can be transposed to either IV or V without much change
- as discussed in the section on the major scale , the interval of a fifth has special significance in tonal music. Triads a fifth apart such as I, IV and V are considered to be particularly closely related
Tonal music is created by progressions rather than single chords. The links in the blue triangle below link to information about a wide range of shorter and longer chord progressions.
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© Copyright Thomas Pankhurst