7th Chords
There are three common types of 7 chords, and each have different characteristics. On this page we're going to be investigating the most common one of all - the dominant seventh chord.
Sound of the 7th chord
This has a very unstable and uncomfortable sound. It is commonly used just before the end of a piece of music (or section of music) to signify "the end is about to happen!"
Dominant 7th Notated
Dominant Seventh chords are notated simply by the name of the chord, followed by the number seven. E.g. G7
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G7 chord notated
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Theory - here's how to work them out.
Dominant seventh chords are constructed from a major chord, followed by the flattened seventh note of the scale of the chord. O.K. so all that sounds a bit complicated - here's an easier way to work them out, if you're not too familiar with scales:-
A7 chord
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Begin by working out the major chord. In this instance, we're going to work out A7, so A major is A - C# -E. The seventh note is found by going two semitones down from the root note (that's the name of the chord - in this example, it's an A). Two semitones down from A is G. Next, put this note up one octave, so that it's now at the top of the chord. So A7 is a four note chord A - C# - E - G .
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In summary, dominant sevenths are major chords, with the extra note being found by going down two semitones from the root note.
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TOP TIP:
Why are dominant sevenths called "dominant"?
This terminology comes from the degrees of the scale. The first note of the scale is refered to as the "tonic", and a chord formed from this note will called the "tonic chord". The fifth step up on the major scale is the dominant note, and so we call this the "Dominant chord", and if it has a seventh present in the chord, the "Dominant Seventh". This relationship of tonic and dominant is fundamental to virtually all music, whether it be folk, classical, hip hop or exotic indian ragas!
If you want to play around with chord, try playing G7 (G - B - D - F) followed by C, and repeating this. This gives you an "over the top" ending to a piece of music. (This device of repeating the dominant and tonic was commonly used at the end of classical symphonic works to signify that this really was the end of the work). |
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