Lesson 25: Subdominant & Dominant
This lesson teaches the
subdominant and dominant chord
functions. This is part of understanding how the different
diatonic chords "work" in
chord progressions.
Before taking this lesson, you should know: the
tonic chord function
(
Lesson 24: Tonic Function).
To review, the
common major-key diatonic triads are:
I IIm IIIm IV V VIm
This lesson explores
IIm,
IV, and
V.
The Subdominant Chords: IV and IIm
Subdominant function. A subdominant chord
feels like you've
moved away from the home chord. It's extremely common for the I chord
to be
followed by a subdominant chord.
The IV chord. "Subdominant" is just a name for "scale degree 4",
so "the" subdominant chord is the
IV chord.
The IIm chord. The IIm chord also has
subdominant function,
meaning that is has a "moved away from home" effect
similar to the IV
chord. Notice that
the
IIm and
IV chords share two of the same pitches (namely,
scale degrees
4 and
6 of the song's
key).
In fact, these two chords are pretty interchangeable.
Reasons a song might choose one or the other include:
-
To create a desired root motion (bassline);
-
The musical style. In jazz, IIm is more common (except it's usually
used in its "jazz version", IIm7); in rock/folk/country (and
classical music), IV is more common (or, in blues, IV7).
The Dominant Chord: V
Scale degree 5 is called the
dominant; so, the
V chord is
called the
dominant chord.
Dominant function. The dominant chord (the
V chord) feels like
it wants to
return to the home chord; it's extremely common for the
dominant chord to be
followed by the I chord.
The Typical Diatonic-Function Sequence
Since tonic "tends to go to" subdominant, and dominant "tends to go to" tonic,
the most
typical sequence of diatonic functions is:
Tonic -> Subdominant -> Dominant -> Tonic
This sequence has a conventional "
advancing" ("moving forward")
feeling. If a chord sequence
reverses this order (tonic -> dominant,
dominant -> subdominant, subdominant -> tonic), it tends to sound like it's
retreating. That's how
I describe it, anyway; but these effects
are subtle and subjective. You should
decide for yourself what you
think the effects of
different diatonic-function sequences are, by
studying the sequences in various songs.
In fact, that's the subject of the next lesson,
Lesson 26: Diatonic Function Analysis.
