Click on the chord to hear the dominant 7th quality. Click on the interval designations to the right of the second chord to hear the intervals individually.
The dominant 7th chord is a four note chord rooted on the dominant tone of the scale. It is always a major triad with a minor 7th from the root. The intervals from the root are M3, P5, m7.
Click on the chord to hear the dominant 7th quality. Click on the interval designations to the right of the second chord to hear the intervals individually.
The 7th of the dominant seventh chord almost always resolves down by step. The reason for this is the interval between this 7th and the 3rd of the chord. This interval is a tritone (o5 or +4). The tritone has a natural tendency to resolve o5 to a M/mi 3rd or +4 to a M/mi 6. Also you will notice that the two notes which are involved in the tritone are the leading tone (3rd of the chord) and the subdominant (7th of the chord). Both these notes have strong tone tendencies; the leading tone going up to the tonic and the subdominant moving down to the mediant. This is the reason for the 7th of the chord (which is the subdominant of the key) to resolve down by step.
Click to hear this tritone
With this is mind it is probably a good idea, when encountering a dominant 7th chord, to first resolve the tritone. Let us resolve the following four voice V7 chord applying this principle. Remember that the tritone occurs between the 3rd and the 7th of the dominant 7th chord.
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The tritone in the dominant 7th chord is F# to C. C is the 7th of the chord so it resolves down to the B. F# is the leading tone which resolves up to the tonic. But observation will show us that this results in an incomplete I chord (3 roots, 1 3rd, 5th omitted). This is as it must be. If you attempted to include the fifth of the tonic chord by moving the tenor from A to D, the result would be parallel 5ths.
In the dominant 7th chord it is possible to omit the 5th of the chord and to double the root. Observe the results when we resolve this chord using the tritone resolution.
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Leading tone goes to tonic; 7th of the chord goes to mediant. With the tenor remaining on the D, we end up with a complete tonic triad. Once again, this is to be expected. All of this results in the formula: Complete to Incomplete; Incomplete to Complete. If we begin with a complete dominant 7th chord, we should expect an incomplete tonic. If we begin with an incomplete dominant 7th (doubled root), we expect a complete tonic chord.
It is possible, however, under certain circumstances to begin with a complete dominant 7th and resolve to a complete tonic. This can be accomplished by frustrating the natural tendency of the leading tone to go to the tonic (also frustrating the natural resolution of the tritone). Of course, if the leading tone is in the soprano, it must go to the tonic. Therefore, this procedure can only be used if the leading tone is in the alto or tenor voices. The leading tone instead of resolving to the tonic skips down a third to the dominant of the key.
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In three voice dominant 7th chords it is customary to omit the fifth of the chord (root, 3rd, 7th). On rare occasions it is possible to omit the 3rd (root, 5th, 7th). The tritone is usually resolved, but again, the leading tone may move down if it is in an inside voice.
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If you still have questions, contact Dr. Bartolotta at wbartolo@odu.edu.