TRIAD, SEVENTH, NINTH, ELEVENTH AND THIRTEENTH CHORDS

Chords can be classified into different categories by their size. That is, by the number of note names they are made of, which also determines the interval they span in their root close position. These categories are: triad chords, seventh chords, ninth chords, eleventh chords and thirteenth chords. In this chapter, we shall explore their properties.

Triad chords in their root close position: have three notes (hence the name), are obtained by stacking two thirds and span a fifth. The note names are called: the chord root, the chord third and the chord fifth. We already defined the chord root as the note name of the lowest note in the root close position. The note name of the next higher note is the chord third and the note name of the last one is the chord fifth. The next figure shows the triad chord having the chord root C, the chord third E and the chord fifth G, in its root close position. Later, we shall learn that this chord is called the C major triad chord.

Figure: A triad chord in the root close position

Seventh chords in their root close position: have four notes, are obtained by stacking three thirds and span a seventh (hence the name). The note names are called: the chord root, the chord third, the chord fifth and the chord seventh. Seventh chords are also called tetrads because they are made of four notes.

Figure: A seventh chord in the root close position

Ninth chords in their root close position: have five notes, are obtained by stacking four thirds and span a ninth. The note names are called: the chord root, the chord third, the chord fifth, the chord seventh and the chord ninth.

Figure: A ninth chord in the root close position

Eleventh chords in their root close position: have six notes, are obtained by stacking five thirds and span an eleventh. The note names are called: the chord root, the chord third, the chord fifth, the chord seventh, the chord ninth and the chord eleventh.

Figure: An eleventh chord in the root close position

Thirteenth chords in their root close position: have seven notes, are obtained by stacking six thirds and span a thirteenth. The note names are called: the chord root, the chord third, the chord fifth, the chord seventh, the chord ninth, the chord eleventh and the chord thirteenth.

Figure: A thirteenth chord in the root close position

Please note that triad chords have tree mutually different note names, seventh chords have four and so on. Thirteenth chords have seven mutually different note names. This is the reason that the fifteenth and higher chords do not exist because they would start to repeat the same note names.  

What is said in this chapter holds for chords without added/omitted tones. Added/omitted tones will be explained later. For a chord with added/omitted tones, if we remove added tones and add omitted tones (that is, erase all additions and omissions) then what is said in this chapter still holds.

When we analyze chords in compositions from the common practice period, we tend to use triad chords, seventh chords and only sometimes ninth chords. Thus, readers should focus on the chapters describing these chords. Often used triad and seventh chords should be learned very well. They will be examined in the following chapters.