One more thing. Play the following simultaneity:
This "filled" chord is specifically called a triad because
of its very particular sound. The reiteration of 1 and 8 becomes understood
and less important than it was in the antique 8-5-1. This does not mean that
any one of 5, 3, or 1 may not be reiteratedthey usually are. It just
means that those three notes are all that's necessary for an ultimate sonority,
after 1600.
You may hear of "inversions" of the triad:
This is often called a "first inversion" triad as opposed to the "root position" triad above. While the "root position" triad is preferred for cadential use, in any other harmonic function, the two inversions are virtually interchangeable.
However, this inversion is considered unstable because 5 is in the bottom. How do you hear it? Does it seem unstable to you?
If it doesn't, great! You are very open-minded and will have an easier time
on our imminent journey into the music of the Middle Ages. If 3-1-5
does seem unstable to you, congratulations, you have been successfully brainwashed
by the cadential formulae which permeate our culture: you expect a 5
in the bottom of the chord to resolve to a 1. Like this!
 |
 |
 |
 |
 |
|
one at a time,
horizontally |
one at a time,
vertically |
all together |
| 7...8 |
 |
 |
 |
 |
| 5...5 |
 |
| 4...3 |
 |
| 2...1 |
 |
| 5...1 |
 |
Now you are probably hearing the most familiar cadential formula of all. ("Amen", anyone?) Notice how the bottom or "bass" notes moving from 5 to 1 helps to enhance and solidify the sense of resolution. This is a classic tonal system cadence.