All books on harmony try to teach you quite a number of difficult things before they dare to trust you with this chord, which is the nicest and most natural one of all. I think it is always best in studying anything whatever to learn the most useful things first; to hark back and pick up loose ends may be unsystematic, but not necessarily confusing.
The chord called the dominant seventh is one of nature’s own manufacture. It consists of a major common chord with a fourth note added, this fourth note being a minor seventh from the bass note and a minor third from the fifth.
If you try you will find that the dominant (5) is the only note in the scale upon which such a combination can be built. Chords similar in appearance can be and are based upon all degrees of the scale, but they all sound more or less harsh and unnatural, while the dominant seventh appeals to the most rudimentary ear as the natural product which it is.
You will hardly need telling that it demands imperatively to be followed by something else – usually the tonic chord; but you will be surprised to find what a number of details there are in this business which will grip you up if you are not careful. First and foremost is the way that the third and seventh must move. The third, being the leading note (seventh degree) of the scale will always want to move up to the key-note, just as it does in common chords. In these we found that it occasionally slid down to 6, but it can hardly do that with good effect in the dominant seventh:
The seventh, you will easily feel, wants to fall a step and very seldom to rise. Yet you will find yourself frequently forgetting this obvious rule in the inversions of the chord, or when the seventh does not happen to be at the top or bottom – in other words, when you do not hear it. Well, I don’t know that bad grammar is an unpardonable crime in music any more than in speech; but I cannot agree with Artemus Ward when he says, “Why care for grammar so long as we are good?” If you have any ear at all you are not likely to make either of the following mistakes –
But you are very likely to commit the following:
A is the least offensive of these; in writing for piano we do not very much mind incorrect part writing in middle parts; b is very disagreeable to those who can hear a bass, but a common lapse with those who cannot. Point out to such an one that it can be agreeably avoided by putting the seventh in the bass and he will receive the emendation with joy; but it will not prevent his making the same mistake again. Nothing will do that till he learns to hear his bass. C is another version of the same fault, less excusable because the seventh is audible, and can only rise.
The best way to guard against faults b, c, and d is to notice that in the dominant seventh chord the dominant itself cannot go down a third. It may move up a step or down and skip a fourth or fifth, but a third – never.
Next comes the important and curious case when the seventh breaks its own rule and resolves upwards instead of downwards. This is when we are using it in the second inversion (as there are four notes to the chord there are, of course, three inversions) and the bass wants to move upwards. Play the following on the piano, listening intently to the bass and treble, then I think further explanation will be unnecessary.
The rising of the seventh is of course to avoid the doubling of the E, which would occur if it descended. This difficult detail of what notes may or may not be doubled I have hitherto avoided, in order that you should not get confused by a quantity of details; we shall presently have to go into the matter thoroughly.
For the present it will be sufficient to point out that no note that has a fixed and obligatory progression can be sued in both treble and bass at once. We have seen this with the leading note, it will be the same with the dominant seventh. Then since two out of our four notes may not be doubled, which may? It is seldom wise to double the fifth of any chord, as it is so apt to lead to consecutive fifths, so only the root is available for that purpose. But as there are four different notes in the chord of dominant seventh you will, as a matter of fact, not often require to double even this.
When one has newly made the acquaintance of this interesting chord – just as when one has learnt a new word – one is apt to over-use it, and you will for some time find yourself positively unable to use a dominant chord at all without sticking in a seventh. Perhaps the following illustration will show you the weakness of this. Suppose this to be the end of a phrase, or the middle of a verse:
In other words, a concord is a thing you can rest upon, like a noun or a verb in speech, but a discord is like an adjective or adverb; it qualifies and passes the sense on; it is incomplete in itself.
That you may get really acquainted with the dominant seventh chord it will be necessary to play the following exercises on the piano in all keys major and minor.
The transposition of these will probably give you some trouble. Take the keys in the following order, each first major then minor; C, G, D, A, E, B, F sharp, E flat, A flat, F, D flat, B flat. I cannot too strongly impress upon you the benefit you will derive from this playing of all the chords and harmony progressions in all the keys. It is the only way – and a certain way – to build up that connection between eye and ear which is the vital part of musical education. Most learners begin by having no notion of the kind of sound any given interval makes; they will play C followed by D, for instance, and quite fail to perceive that E followed by F sharp (and not F) will produce a similar musical effect.
To return to our dominant seventh. Having grasped the fact that the tonic chord is the thing it really needs to follow and complete it, we must now find if there is any other that will do instead. There are three really, but only one of any account.
- The chord on the sixth degree (submediant)
- A first inversion on that note, or a second inversion on the tonic (two position of the same chord).
- Flatten or sharpen any one of the notes and so slide into a fresh key.
A is agreeable and is generally called “the interrupted cadence.” The effect on the ear is that we were on the point of finishing and changed our mind. You may try placing the chords in inversions, but you won’t like the result.
B sounds better the second way I have given it than the first. But it is not final, because, as you know, the second inversion will need a direct common chord after it. The dominant seventh sounds equally well this way in the inversions.
C introduces us to a new feature, called modulation.
We are switched off into a new scale and key; our dominant seventh has disappeared, but has been replaced by another, which will have to be disposed of in one of the way already described, or else followed by yet another. It is not uncommon in music to find a whole procession of chords like this, each one dragging us into a fresh key, and perhaps coming back after all to where we started; for instance, in Chopin’s pretty Variations, op. 12.
I have been thus minute over the details connected with this chord because I know from long experience just what errors you will be likely to commit in employing it. You may fully appreciate examples 2, 3, and 4, but yet in harmonizing a tune that rises from the fourth to the fifth degree you may easily put a dominant seventh to the first note because it sounds so nice, only to find that you cannot follow it correctly. One begins by hearing one sound (or bunch of sounds) at a time; we have now to hear also what the next sound is going to be before it has come. And this is the most important stage in the development of our ear. Try to think of this dominant seventh chord with its ordinary resolution (that means the chord that completes it) as the first syllable of the word A-men. The various ways which it behaves might then be compared with other words: e. g.