VISUALIZATION OF CHORDS

In this chapter, we shall explore a simple idea of how to visualize chords. Such visualization illustrates relationships between chords, chord tones and nonchord tones and helps us to better understand them. For this purpose, we shall visualize chords in Chopin’s Prelude No. 11 in B major.

In chapter Parts, we explained so-called Piano roll view, used often in music software. In this view, the horizontal axis corresponds to time while the vertical axis corresponds to pitch. Piano roll view is very convenient for showing melodic patterns. 

Here, we shall construct a view that is convenient for showing chords. For this purpose, we shall put time on the horizontal axis and scale degrees on the vertical axis. Scale degrees were explained in chapter Scale degrees. Scale degrees will be used in the context of the key. We shall order the scale degrees in a special way. After each scale degree, we shall skip the next one. That is: first, third, fifth, seventh, second, fourth and sixth. In fact, we can start from any scale degree. For instance: second, fourth, sixth, first, third, fifth and seventh is equally good. An altered (raised or lowered) scale degree will be positioned on the vertical axis in the same position as its non-altered equivalent.

In such a view, any chord constructed as a stack of thirds (tertian harmony) will occupy a rectangular area. We can see this in the next figure where the yellow rectangles represent chords. The smaller blue and red rectangles represent notes. The blue rectangles, which always fall into the yellow rectangles, represent chord tones. The red rectangles, which always fall outside of the yellow rectangles, represent nonchord tones.

The next figure shows the beginning six measures from the prelude. We see the score together with the annotated chords and nonchord tones. The visualization of chords is shown below the score. The scale degrees of the B major key are used on the vertical axis. The visualization shows notes and chords from the prelude. The first chord is the B major triad chord and lasts for the beginning two measures. It is represented with the yellow rectangle spanned over the first two measures on the horizonatl axis and the scale degrees that form the B major triad chord (the first, third and fifth in the B major key i.e. B, D# and F#) on the vertical axis. 

Figure: Visualization of the beginning six measures from Chopin’s Prelude No. 11 in B major

We see that the B major triad chord is loosely implied with four chord tones (three instances of the fifth and one of the third scale degree in the B major key - shown as blue rectangles) and there are also three nonchord tones (the raised fourth, fourth and sixth scale degree in the B major key - shown as red rectangles).

The next chord is the F# dominant seventh chord. It is represented with the yellow rectangle spanned over measures 3 and 4 on the horizontal axis and the scale degrees which form the F# dominant seventh chord (the fifth, seventh, second and fourth in the B major key i.e. F#, A#, C# and E) on the vertical axis. It is strongly implied with twenty chord tones and there are also four nonchord tones. We can say that more of a yellow rectangle is tiled with blue rectangles, the stronger is the implication of the chord.

The next figure shows the following six measures from the prelude. 

Figure: Visualization of the following six measures from Chopin’s Prelude No. 11 in B major

The next figure shows the following five measures from the prelude. We see that the yellow rectangle which represents the E major triad chord starts in the top row and continues in the bottom two rows. By placing the sixth scale degree on the bottom of the vertical axis, we achieved that there is only one such a chord in the figures. This is not important but it makes the figures simpler to understand.

Figure: Visualization of the following five measures from Chopin’s Prelude No. 11 in B major

The next figure shows the following five measures from the prelude.

Figure: Visualization of the following five measures from Chopin’s Prelude No. 11 in B major

The next figure shows the last five measures from the prelude. 

Figure: Visualization of the last five measures from Chopin’s Prelude No. 11 in B major