So far we have encountered the triad in its most basic form: as a pitch with a third and a fifth directly above it. But if we add certain tones, we can still consider it a triad. These added tones must be either "duplicates" of tones from the triad in a higher or lower register, or else ornaments to tones of the triad.
Expanding the Triad by Adding "More of the Same" Tones
The simplest way to add tones to the triad is by adding tones that are "duplicates" of tones from the triad in a higher or lower register. One of the reasons that the octave is such an important interval in music is that when two tones are exactly an octave (or several octaves) apart, they share the same identity, though separated by a difference in register. That is, they are in some meaningful way the same tone, even though one is higher than the other. This is illustrated in the video example below.
If we add tones that are exactly an octave away from tones in the original triad, they will blend in very smoothly. The result will have a sound that is similar in important ways to the original; it will still be considered the same triad. Here's a simple example of that. We'll add a tone exactly an octave above the root of the triad.
Below are sound examples of these two versions of the triad. Play each a few times. They don't sound the same; especially having different top notes makes them sound quite different. But there is nonetheless something very similar about their sounds. They are considered to be the same triad.
When adding tones, we can do this both above and below the original pitches. Here's a triad in which we've added a tone an octave below the fifth.
Not only can we add tones, we can also move tones of the original triad by exact octaves. In Video Example 3, we take a low triad and raise the fifth by one octave and the third by two. This is still considered the same triad.
We can now go back and fill in all of the pitches in the middle that are exact octaves away from some pitch already in the triad. We still call this the same triad.
To make things still more complicated, we can add extra notes to decorate the notes that belong to the triad. These extra notes have a somewhat different status than that of the octave duplications discussed above. When tones are exact octaves away from the tones of the triad, we still consider that these tones belong to the triad. Ornamental notes, however, never really become part of the triad. Ornamental notes come and go, getting mixed in with the tones of the triad, but because of the stability and prevalence of the tones of the triad we are able to hear that one triad is serving as a structural framework for a complex musical passage.
A famous example of an ornamented triad is found at the beginning of Mendelssohn's overture, Fingal's Cave (also known as The Hebrides). First, here's the underlying triad.
The orchestra plays the root and the fifth of the triad, with notes duplicated at the octave. It leaves the third for the melody. The notes used are these:
The instruments playing the melody are going to have a motive based on the triad:
To make it more interesting, Mendelssohn adds a note that doesn't belong to the triad. It's right next to one of the triad notes, so they play it briefly and then go right back to its neighbor in the triad. Mendelssohn's melody is given in the illustration and example below; the newly added note is the third note in the melody.
Repeat the last two examples until you can hear clearly how they are related. Then go back to the other examples of this triad, and make sure you can hear that they are all expressions of the same underlying triad. Finally, listen to the first few bars of the overture, played by the orchestra.
This lush and complex texture is all an elaboration of a single underlying minor triad.
One of the most famous examples of elaborating a single triad is the Prelude to Wagner's opera The Rhine Gold. The entire Prelude can be reduced to one chord which lasts more than four minutes. Here is a relatively brief excerpt:
If you got a good grasp of distinguishing major and minor triads in the training offered at the end of the last lesson, then hearing that difference in elaborated triads probably won't be particularly difficult as a next step. Still, it's an important stage in the process hearing music as being in major and minor keys. As usual, there's a training environment to help you develop this skill.
Lesson 4 Summary