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It's been a very long time since my last post, but I said I'd be looking at diminished chords.
Diminished Chords A bog standard plain diminished chord, is in reality nothing more than a standard minor chord triad (which as I've stated before has a scale spelling of 1, b3, 5) and flattening the 5th note as well. So going back to C you'd get. 1 = C b3 = Eb b5 = Gb So this would be called a C diminished chord. Half-Diminished or m7b5 chords So how do we make it a half-diminished chord. Well bizarrely a half-diminished chord is really a minor 7th chord (remember the scale spelling for that 1, b3, 5, b7) but with the 5th flattened also, so you get 1, b3, b5, b7. So again in C. 1 = C b3 = Eb b5 = Gb b7 = Bb So if you think about this as it's a minor 7th chord with a flattened 5th, it's become more popularly known as a minor 7 flat 5 (m7b5) chord and certainly in popular music you'll find more people who know it by that name, rather than half-diminished. Diminished 7th chords So how do you make a full diminished 7th chord. Pretty easily actually. All you need to do is take a half-diminished (m7b5) chord and flatten the 7th note AGAIN. Yes that's right again. So the scale spelling of a diminished 7th chord is 1, b3, b5, bb7. So again in C you get these notes. 1 = C b3 = Eb b5 = Gb b7 = Bbb (yes music theory caters for double flats so whilst it's actually the same note that we'd generally call A it's called Bbb).
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There are a number of 7th chords available. This post is concerned with the following three types
Major 7th Minor 7th Dominant 7th (this is the one most guitarists know when they're asked to play a 7th chord i.e. C7) Major 7th Going back to my earlier post on major chord construction you'll see that major triads are made up from the 1st, 3rd and 5th notes from the major scale. To create a major 7th chord you simply add the 7th note of the major scale. So using the good old C Major scale as an example. You get C (1st note of the scale) E (3rd note of the scale) G (5th note of the scale) and B (7th note of the scale) Therefore the scale spelling of a major 7th chord is 1, 3, 5, 7 Dominant 7th Slightly different from a major 7th chord. This chord uses a flattened/minor 7th note. So in the case of a C dominant 7th (or C7 to you and me) you get the notes. C (1st note of the scale) E (3rd note of the scale) G (5th note of the scale) and Bb (flattened/minor 7th note of the scale). Therefore the scale spelling of a dominant 7th chord is 1, 3, 5, b7 Minor 7th This chord is an extension of the minor triad and as such is based on the natural minor scale and uses the 1st, 3rd, 5th and 7th notes from that scale. C (1st note of the scale) Eb (2nd note of the scale) G (5th note of the scale) Bb (7th note of the scale) Therefore the scale spelling of a minor 7th chord is 1 b3, 5, b7 (don't forget scale spellings are relative to the major scale not the minor scale). So if you review my other posts on major scale construction and the circle of fifths you should (in theory at least - pardon the pun) be able to work these chords out in any key. We'll discuss diminished 7ths later when I cover diminished chords. |
This theory blog is currently being replaced with a structured theory section. In the meantime you might find some duplication so apologies in advance for that.Archives
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