Secondary chords I – secondary V and V7
What this type of chord does:
A secondary chord is a dominant function chord that is not the dominant chord in the key of the piece, but is the dominant of one of the other major or minor triads in that key.
This process is called tonicization: making a triad other than the tonic sound momentarily like it is the tonic, by preceding it with its dominant. Only triads that are major or minor can be tonicized.
Secondary chords can be inserted into any diatonic progression, to tonicize particular chords in that progression. Secondary dominants are chromatic chords, since they always require one or more accidentals to create the correct chord quality.
There are always two chords involved in this process of tonicization, the secondary dominant chord and its chord of resolution. The musical effect of these chords is twofold, chromatic colorization of the progression and a stronger pull to resolve to the next chord than is possible with any of the diatonic chords of the key.
How these chords are spelled: Think in the key of the chord that you want to tonicize, and then spell out the V (major triad), or V7 (Mm seventh chord) chord in that key.
For example, in the key of C major, we could create a dominant triad or dominant seventh chord of one of the other triads in the scale (but not I or viio), such as the V7 chord of ii. That chord is the secondary dominant, which would then resolve to the ii chord.
Let’s look at an example where we tonicize the ii chord in the key of C major. The ii triad in the key of C is d minor; therefore we need to think temporarily in the key of d minor: the V7 of d minor would be an ‘A’ dominant seventh chord (A, C#, E, G). Although this particular secondary chord is built on the sixth scale degree of C major, the note A, it is not labeled using the Roman numeral vi, nor is it the same as the diatonic seventh chord vi7 found on that step of the scale, since it contains the note C# instead of the note C. This may seem like a small difference, but it is a crucial one – the C# creates a major-minor seventh chord quality which our ears immediately identify the function as V of another triad, rather than as any sort of vi chord in this key. This is the whole reason this concept works, and why getting the accidentals correct is so important.
This progression (V7/ii - ii) will sound as if we were momentarily in the key of d minor, hearing the progression V7 – I; however, the rest of the progression before and after it remains in the key of C. The secondary dominant chord is used to give our ears a strong pull to the ii chord in the progression. Here is a musical example of the progression I – V7/ii – ii – V – I in the key of C.
Put audio and musical example of this here
Here is another example: if we want to tonicize the V triad in the key of A major, E major, we will need to build the dominant triad of E major, which is a B major triad (B, D#, F#). Notice that this chord requires the chromatic note D#.
This is just an overview of the concept. There is much more detailed information about spelling secondary chords in major and minor keys further below.
How this chord is indicated in musical analysis: When we write the musical analysis for a secondary chord, we use a “slash” notation, looking rather like a fraction. The slash sign can be thought to represent the word “of.” For example, V/vi would be read as “five of six,” referring to the dominant chord of the triad on the sixth scale degree. V7/V would be read as “five-seven of five.”
Resolution of secondary chords: Secondary dominant chords are resolved in the same way as a dominant chord would in diatonic harmony. The secondary dominant resolves to its tonic, taking special care with the active tones: leading tones want to be resolved up to their tonic note, and sevenths, if present, should resolve down by step.
Like in diatonic V7-I resolutions, certain voicings of the dominant seventh chord in root position may require use of an incomplete chord on either the secondary chord or the chord of resolution. This is one of the more complex things we learned about resolving V7 correctly, and it is just as important here when resolving secondary dominants. If you need to review this, you can read the tutorial on resolving V7.
If you are familiar with the complete/incomplete concept, you may remember that sometimes a root position V7 ends up resolving to an incomplete tonic chord, with three roots and a third. While this works well at a final cadence, it may not be as desirable when the chord of resolution is a triad other than the tonic chord in the middle of a musical phrase, as is the case with secondary dominant resolution. If there are three voices on the same pitch, it creates an increased opportunity for parallel octaves or awkward voice leading when moving to the next chord. Consider using secondary V7 in an inversion if possible instead, or if needed in root position, make the secondary V7 incomplete so that the chord of resolution does not have a tripled root.
Imagine for a moment that these two chords, the secondary one, V7/vi, and its chord of resolution, vi, are the only chords in the progression. The voice leading will work exactly like a typical resolution of V7 to i. The fact that the larger chord progression surrounding it is in another key does not change anything about the way the secondary V7 chord resolves to its tonic. All voice leading rules work exactly as you have previously learned when resolving V7 diatonically. A few examples follow. Notice that the sevenths of dominant seventh chords still resolve down by step, and leading tones generally resolve up to the tonicized note as appropriate. Also, notice whether the secondary chord is complete or incomplete; notice the same about the chord of resolution. Lastly, when tonicizing V at a cadence, sometimes the cadential I6/4 chord intervenes before the V.
Give some examples of chords resolving here
Tips for resolving secondary dominants:
When resolving dominant sevenths, it is always important to take care of the notes that need to resolve in a particular way first. There are two such notes in a dominant seventh chord, the leading tone and the seventh. In the above example of an A7 chord resolving to d minor, the C# is the leading tone, which will resolve up to the temporary tonic d, and the seventh of the chord is the note G, which will resolve down to an F. Once these two notes are resolved, and the bass entered as required, it should be easier to see where to move the E. Just be sure you avoid parallels, or other poor voice leading. Move the voices smoothly. If you find you need review on resolution of V7 chords, please see the resolving dominant seventh chords page.
Secondary chords also follow all other rules that we learned when using them diatonically, such as which notes may be omitted or doubled. The fifth of the V7 may be omitted, and the root must then be doubled. In other words, there are no new rules for resolving dominant seventh chords just because they are secondary. We need to follow the same rules we learned when resolving them as diatonic seventh chords. This is a big reason why learning how to resolve a dominant seventh chord properly is so important.
Secondary Dominants in Major Keys
Although there are seven triads in the scale, there are only five that may have secondary dominants. The tonic triad must be eliminated, since it already has its dominant in the key. Because it is already the tonic, there is no need to tonicize it. Also, tonic chords can be only major or minor, since our tonal system is structured this way. Therefore any diminished triads present in the scale cannot function as tonic chords. In a major key, this means that viio will not be tonicized. That leaves ii, iii, IV, V, and vi as the triads that can be tonicized in a major key.
Either a V triad or a V7 chord can be used to tonicize, with one exception: the triad that would be the V of IV. We can use the key of C for our thinking key to figure out why. The IV triad is F major, so we need to determine the V chord of F. You will realize that this turns out to be a C major triad. But C major is the tonic chord, so we most likely will not perceive it as a V when we hear it - it will just sound like I. Therefore, if we truly want to tonicize the IV chord, we need to use a V7 chord instead: that will be a C dominant seventh chord, which contains the chromatic note B-flat. This chromatic chord will clearly have a dominant function when it is heard.
Important details about spelling secondary chords
When spelling secondary dominants, it is important to be accurate when locating the root of the secondary chord. Be careful to precisely figure a P5 above (or P4 below) the scale degree you want to tonicize. Or think in the key of the note you want to tonicize and find the fifth step of that scale. Remember, perfect fourths and fifths follow the matching rule described in an earlier lesson, so you may wish to review that principle since it can be very helpful here.
Labeling secondary dominants:
One thing that always causes confusion is that the analysis symbol for a secondary chord does not directly indicate the step of the scale that the secondary chord is built on. For example, a V/V chord is actually built on the second step of the scale, since the second scale degree of the key is also the fifth step of the key of the dominant note.
Since it is not directly obvious where the root is located from the analysis symbol, this makes it more difficult than usual to see if you have the correct notes. This is why it is important to be very careful when finding the root note of the dominant chord of the triad you want to tonicize. As you work more with these chords, you will begin to learn these secondary relationships. Knowing where the root of the secondary chord is in the scale will help you think where you can use this chord easily. (V/V is built on the second scale degree, V7/ii is built on the sixth scale degree, etc.) For example, when wishing to add secondary chords to the progression I - ii - V - I, you might realize that instead of just inserting the V/V chord before the V, you could actually substitute the V/V chord for the ii chord instead, since it is almost exactly the same harmony, except for the one accidental.
Another thing to notice about secondary chords in major keys is that, other than the V7 of IV described above, which requires its seventh to be lowered one half step, all the rest of the secondary dominant chords require only raised notes. If you find yourself lowering notes when creating a secondary dominant other than V7/IV, start over and make sure your root note is correct.
Observe the type and placement of the accidentals in the secondary dominants in the chart below.
You will notice that most of those raised notes occur on the third of the V or V7 chord, which is the leading tone of the tonicized chord. These leading-tone raised notes want to resolve upwards. Notice there is only one chord with a lowered note, which happens to fall on the seventh of the chord V7/IV. Lowered notes generally want to resolve downwards, and that is certainly the case with sevenths of chords. Generally in chromatic harmony, the accidentals themselves point to their proper resolution - raised notes go up, lowered notes go down.
Because we usually need raised notes to build these chords, you will find it sometimes requires a double-sharp accidental when you are working in a key with several sharps in the key signature. For example, in the key of E major, this occurs when spelling out the notes in the V7/iii chord. G# is the third step of the E scale. We need to build the dominant seventh chord of G#. The root of that chord will be on the note a P5 above, D#. The chord will consist of the notes D sharp, F double sharp, A sharp, and C sharp. The D# and C# are already in the key signature; the F double sharp and the A sharp are both accidentals. Do not respell any notes enharmonically. The secondary chord needs to remain spelled in thirds, according to its function.
Secondary Chords in Minor Keys
Secondary chords in minor work the same way as in major: we don’t tonicize the tonic or any chords that are not major or minor triads. This means we cannot tonicize the iio chord, since it is diminished. The triads that can be tonicized are III, iv, v, VI and VII. Like in major, there is one place where the secondary V triad is just a regular triad in the key: in minor keys it is the V/III, which is just the diatonic triad VII. Again, as in major, most of these chords will require raised notes which are mostly notes functioning as leading tones; only one requires a note to be lowered, the V7/VI which requires the seventh to be lowered one half step.