SUMMARY: This debut article takes a reasonably deep look at a basic topic. It describes the dominant chords, which are often referred to as V and V7. I’ll also illustrate how the chords function, how they’re used, and I’ll end with some examples. You’ll learn that a dominant chord can be used alone, or you can assemble a hierarchical sequence of them for a powerful and compelling journey back to the tonic. There’ll also be a brief glance at the overtone series and at the circle of fifths.
The V-I move
Let’s say that your song’s chorus, in the key of C, comes to a triumphant end with a G chord followed by a C chord. That’s an example of the key’s dominant chord followed by its tonic chord. The dominant chord’s root is the fifth degree of the scale (the G note in the key of C), and so it is notated analytically as V (because we use Roman numerals for chords). The tonic chord’s root is of course the first degree of the scale, so we use the Roman numeral I. Analytically, then, your G-C dominant-to-tonic move is written V-I, and pronounced “five-one”. G7-C is an example of a V7-I move. A V7-I is a V7-I no matter what key you play it in. So, with this notation, you can reason about how music works in a way that carries across the specifics of particular keys and chords.
V-I and V7-I are arguably the most popular and most effective of all chord changes. But why is that? And what’s the magic contained in these moves that makes them so effective? Let’s begin to answer that with a look at what’s known as the dominant function.
The dominant function
In analysis, Arabic numerals (the numbers we all use) represent scale degrees. Let’s try something. Go ahead and play 1-2-3-4-5 of a major scale (in the key of C, that’d be C-D-E-F-G). Hold that 5 for a moment, then play 1 (the C note) again. You probably felt that the pause on 5 left you hanging somewhat, and then playing 1 felt like a return home to rest. You can get a comparable effect from 1-5-1, or even simply 5-1. Scale degree 5 is known technically as the dominant, and the triad formed with 5 as the root (5+7+2) is known as the dominant triad, or V. The dominant function is simply this: the 5 scale degree tends to sound unstable, and it creates a demand for the 1 scale degree. If you dress up 5 and 1 in triads, you can then similarly say that V is unstable and it creates a demand for I. You, as the songwriter, can choose to yield to that demand and to immediately resolve the tension you’ve generated. That’s the V-I move. Alternatively, you can choose to resist the demand, and to resist resolving the tension, by either remaining on V or by moving to some chord other than I.
So, the dominant function is not the same thing as the V-I move; but it’s part of the engine that drives the move. Before we look at the other parts of that engine, and also at the V7-I move, let’s spend a moment on the topic of tonality, since it’s a concept closely linked to the dominant function.
Tonality and overtones
Tonality is the sense of a hierarchy of stabilities existing between the scale degrees, with the tonic being the most stable. A belief that the origins of tonality can be found in a phenomenon known as the overtone series is associated with such names as Helmholtz, Riemann, Hindemith, Leonard Bernstein, and George Martin. Certainly it’s demonstrable that the degrees of diatonic scales are generated by the overtone series. So what is it? Imagine a string, or a column of air, vibrating with a single fundamental pitch, which is the pitch you’re consciously aware of hearing. Subconsciously you’re also hearing a series of overtone pitches that Nature creates by the vibration of regular subdivisions of that same string or column of air. If the fundamental is the tonic scale degree, then the first overtone is a perfect octave above that, so it does not generate a new scale degree. But the second overtone is a compound perfect fifth above the fundamental, and that overtone creates the dominant scale degree (or 5). Additional overtones, even higher-pitched but much fainter, form additional scale degrees. So, you could say that the dominant scale degree is a pitch that is generated by an object vibrating at the tonic pitch. With the fundamental as the tonic, and the other scale degrees as pitches generated from this tonic by Nature itself, we get a glimpse into the origin of the hierarchy of scale degrees, and consequently their relative stabilities as we perceive them.
A consequence of tonality’s hierarchy of stability (that hierarchy being generated by the overtone series) is that playing a less stable scale degree tends to lead the ear to a more stable one. In the case of the dominant function, 5 leads us to 1. But there are other tone-changes at play in V-I that lead the ear in comparable ways. You’ll remember that the V chord is formed from the scale degrees 5+7+2; and I is 1+3+5. 7 and 2 are the other parts of the engine that drives the V-I move. Both 7 and 2 have an instability that creates a demand for 1.
V7 is 5+7+2+4, and the instability of 4 creates a demand for 3. But V7 also contains the very unstable interval of the tritone (or diminished fifth), which appears in the V7 in the interval from scale degree 7 up to 4. The tritone interval is so discordant that it was referred to centuries ago as “the Devil in music”! During the V7-I move, this discordant tritone between 7 and 4 collapses inward a semitone at both ends, and the result is the stable and restful concord of a major third from 1 up to 3. All of these effects account for the voice-leading that can be seen as the notes of V or V7 are replaced by the notes of I during a V7-I or V-I resolution.
Once you understand that V and V7 serve to generate instability and tension and a demand for I, you can use those effects to whatever artistic ends you see fit. Painters paint with light. Musicians and storytellers paint with drama and suspense. So, let’s look at some examples in well-known songs of how this painting can be done.
Spotting V-I in the wild
Here are two Beatles examples. First, their cover of “Twist and Shout” (Berns/Medley), in the key of D, contains a thrilling example of a V7-I move. Beginning at 1:24, note-by-note the vocal harmonies construct an A7 chord, which ends up being sustained for a period of six full bars before finally resolving ecstatically to D.
“When I Get Home” (Lennon/McCartney), in the key of G, ends with a satisfying D7-G move in the last two bars. But the bar before the D7 contains an A7. If D is “the V”, then A is “the V of V”, or “V/V” for short. V/V is an example of a secondary dominant. Analytically, it makes more sense to regard that A7 as a V7/V instead of as a II7. We can see that the A7 does exactly what we’ve seen V7s doing all along: it contains the dominant function, it sounds unstable, and it creates a demand for the tone or chord a fifth below it, which is D7 in this case. Incidentally, you can say “the tone or chord a fifth above” and “the tone or chord a fifth below”, or you can do what the 19th century music educator John Curwen did and opt for the shorthand terms “over-fifth” and “under-fifth”, respectively. For what it’s worth, I favor the shorthand, but I omit the hyphen.
The circle of fifths
Look at the circle of fifths, and you’ll see the A-D-G from “When I Get Home” forming three consecutive counter-clockwise stops. Analytically, that’s II-V-I (although as we’ve said, V/V-V-I sheds more light on the dominant functions that are at work). The Beatles could have extended this itinerary indefinitely by adding more and more stations to their journey. They might have prefixed that A-D-G with E (which in the key of G is VI, or V/V/V). They might then have further prefixed that with B (which is III, or V/V/V/V). And so on. Each additional leg contributes a new level of dominant-function hierarchy and cranks up the tension, and the eventual resolution, another notch.
At its heart, the dominant function is a root movement (the root moves down a fifth). That makes the circle of fifths a useful reference tool, but it also means that minor-quality chords perform the function as well as major-quality ones. ii-V-I (or v/V-V-I), for example, is just as much a string of dominant-tonic resolutions as is II-V-I. The songs “Moon River” (Mancini) and “I Will Survive” (Fekaris/Perren) contain extremely lengthy excursions around the circle of fifths to great effect, and the chords involved are not necessarily all major.
Give delayed gratification a try!
How do you use the dominant function in your songs? Are there ways in which you can use it differently? Do you use secondary dominants, perhaps whole hierarchies of them to create a conclusive and dramatic, if delayed, sense of returning home? If you always give in to the urge to resolve immediately to the tonic, try holding on to that dominant for a while, or going somewhere other than the tonic. You might find that it adds some extra drama and spice that you like! Why not share your discoveries, if you feel so inclined, in a discussion on Meetup!