UNIT 10 – TONAL FUNCTIONS. RELATIVE TONES, PARALLEL KEYS AND
ENHARMONIC TONES. THE NEIGHBOR TONES. MODULATION.
1. Introduction to Tonal Functions. The degrees.
In a tonality (key), viewed as a scale, we refer to the notes using the degrees (Roman
numerals).
Within the context of a tonality, there are degrees that generate more or less tension for us,
while there are other degrees that produce stability. For now, we just need to keep in mind that
there are three tonal functions (tension levels): Tonic, Subdominant, and Dominant.
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Tonic: The tonic function is the one that gives us the most stability. We perceive it as a
home or a resting point. There are several degrees with tonic function, but the most
important is I.
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Dominant: The dominant function is the one that produces the most tension. It has the
need to resolve to the tonic. There are several degrees with dominant function, but the
most important is V.
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Subdominant: The subdominant function is a midpoint between the Tonic and the
Dominant in terms of tension level. It is a little more tense than the tonic, but not as
much as the dominant. It usually serves as a bridge between the two. There are
several degrees with subdominant function, but the most important is IV.
Following this, the most logical sequence of degrees would be: Tonic - Subdominant Dominant – Tonic, since it goes from less to more tension.
2. Relative tones.
We call relative keys the keys that share a key signature. The relative key of a major key is
minor, while the relative key of a minor key is major. In other words, they are inverses in
mode (major and minor).
The relative of a major key is always the scale starting from the VI. That's why they share the
same notes, but have different functions. To think about it quickly, it's the same as a
descending minor third from the I degree.
In the opposite case, the relative of a minor key is the scale starting from the III of the minor
mode. To think about it quickly, it's the same as an ascending minor third from the I degree.
3. Parallel Keys.
Parallel keys are tonalities that share the name of the first note (the name of the Key), but not
the mode (major and minor). For example: C Major and C Minor are great examples of
parallel keys. They share the tonic (I) but they are different keys and in different modes.
4. Enharmonic tones.
Enharmonic tones are those whose degrees have different names but the same sound.
We can say that, for example, F# and Gb are notes with different names as they sound the same
(they are enharmonic notes).
Therefore, the keys of F# and Gb are also enharmonic.
As you can see, the key signatures are different, but the scales sound the same.
5. The Neighbor Tones.
We call neighbor tones the closest keys by looking at the circle of fifths. They are tones that
share many characteristics, as well as most of their degrees.
To find the neighbor tones of a key by looking at the circle of fifths, you have to look at the
key of its left and right, as well as their relative tones.
For example, the neighbor tones of C Major are: F Major, G Major, A minor, E minor and
D minor.
Another way to find the neighbour keys of a tone is thinking of its IV degree, V degree and
their relative tones.
EXAMPLE:
IV: C MAJOR
G MAJOR
V: D MAJOR
Relative: A MINOR
Relative: E MINOR
Relative: F# MINOR
6. Modulation.
When composers write their works, they look for variety to capture the listener's attention. For
this reason, musical works are generally not written in a single key, but move between several
tonalities.
When we travel from one key to another, we say we've modulated.
When we travel to the new key, we must respect its key signature. Therefore, we can detect it
at a glance by looking at the score. Either a change of key signature appears or the notes are
accidentally altered.
When composers make modulations, they try to make them as natural as possible so that it is
not too noticeable. There are different techniques for modulating that we will see in the future.
It is also very common to modulate to the neighbor tones, as they are the closests and it is
easier to modulate in the most natural way possible.
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