What is the SubV7 chord?
SubV7 is an abbreviation for “Substitute of V7“. Popularly, it is read as “sub-5“. As
its name says, it is a chord that serves as an option to replace the fifth degree.
We know that V7 is a dominant chord, so its substitution must also be a dominant
chord. So far, our study has been restricted to making substitutions only by taking
chords within a tonality using the concept of harmonic functions. We will now work
on new concepts. Get ready to think “outside the box” a little.
Consider the II, V, I progression below:
| Dm7 | G7 | Cmaj7 |
The SubV7 chord in this progression will be a chord that will substitute G7, that is,
stay in its place (hence the name: “substitute of the fifth degree”). In the example
above, SubV7 is the C#7 chord (we will explain this shortly), forming the following
cadence:
| Dm7 | C#7 | Cmaj7 |
Where did we get this C#7? As a rule, the subV7 chord is a major chord with the
minor seventh that is located one semitone above the tonic that it will resolve.
Since the tonic here is the Cmaj7 chord, the major chord with the minor seventh
that is located one semitone above it is C#7.
Great, we have introduced a rule here, but you must be finding it strange, after all
the C#7 chord in the example above does not belong to the key of C! That’s true.
However, as we will see further on, not everything in life revolves only around the
tonal context. We will help you to lose some of that prejudice.
The effect of the subV7 chord is in the chromatic approach. Note that the C#7
chord has 3 notes that are located one semitone immediately above the notes that
make up the Cmaj7 chord. Compare:
● Cmaj7 notes: C, E, G, B
● C#7 notes: C#, F, G#, B
This chromatic approach effect allows the C#7 chord, even though it does not
belong to the key of Cmaj7, to be used to form a cadence. In addition, because it is
a major chord with the minor seventh, SubV7 has a tritone, characterizing it as a
dominant chord, allowing for its substitution by V7 from the point of view
of harmonic function.
To help convince you that it is possible to substitute V7 for subV7, notice that the
notes of the G7 tritone, in the previous example, are the same notes as the C#7
tritone:
● G7 tritone: G, B, D, F
● C#7 tritone: C#, F, G#, B
We will now summarize the reasons why this substitution is possible:
● Most subV7 notes are located one semitone above the chord that it will
resolve, providing a sense of chromatic approach.
● The notes for the V7 tritone are the same as the notes for the subV7
tritone.
● The subV7 is also a dominant chord, allowing its substitution by the V7
not to interfere with the harmonic function of the respective portion of
the song.
How to use the SubV7 chord
Theoretically, the subV7 can always substitute the V7. In practice, however, this is
not the case, as this substitution will not always go well with the melody. It is
always necessary to check and experience the taste that the subV7 will give to the
song when played along with the melody. If it doesn’t sound right, it should be
avoided.
Some musical styles like Jazz, Bossa Nova and MPB usually use the subV7 a lot.
Other “squared” musical styles (less harmoniously developed) usually do not
accept subV7 well.
Whenever it is possible to use subV7 in a song, all the approaches we have studied
for the dominant V7 also apply to subV7 from a harmonic and melodic point of
view, such as, for example, the concepts of secondary dominant, deceptive
resolution, extended dominant, etc.
Example of secondary subV7:
| C | Gb7 | F |
We already know that a dominant secondary chord is one that prepares for
another diatonic degree (other than the 1st degree). In this case, the subV7
prepared for F (4th degree of C tonality).
Example of subV7 with deceptive resolution:
| Dm7 | Db7 | F |
The expected resolution here was C major, because Db7 was acting as subV7 of
G7 (The natural sequence would be Dm7 – G7 – C). The F chord is an unexpected
resolution in this context.
Example of extended subV7:
| E7 | Eb7 | D7 | Db7 | C |
In this example, we had four subV7 chords together in sequence.
We can also have extended II – V progression:
| Dbm7 | C7 | Bm7 | Bb7 | Am7 | Ab7 | G7 | Cmaj7 |
Note how the subV7s in this example are resolving in minor chords (eg: C7 – Bm7)
and these minor chords are already serving as second degree for a new II – V
progression. The series ended with Ab7 – G7 for G7 to then act as the dominant
V7 of C.
