Diminished 7th Chords Are Like Magic Doorways To Other Keys & Other Chords!

This is Duane Shinn, and I would like to ask you a question: Do you know about the 3 diminished seventh chords? If not, you’re in for a great surprise because a diminished 7th chord is a chord that leads everywhere.

First of all, what is a diminished seventh chord? Well let’s take chords in general. That’s a major chord. If I add the seventh note of the scale, that’s called a major seventh, but a normal seventh, like C seventh … you’ll lower the seventh. It’s a flat seventh in other words.

A diminished triad is where you lower the third and the fifth a half step. That’s a diminished triad, but a diminished seventh is you have the seventh plus you lower that half step. It’s a diminished seventh. The seventh itself is diminished. It’s not only a diminished chord, but the seventh is diminished by lowering it a half step.

There’s only 3 of those chords, believe it or not. There’s a [inaudible 00:00:52] chord, and there’s 12 possibilities on the keyboard … Right, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, right? Only 12 different keys you can play … Only 12 different notes. I’m playing 4 of those 12. That’s one-third of 12, isn’t it?

If I move up half a step, all the notes up half a step, then I’ve also got a seventh diminished chord there, don’t I? That’s still a diminished seventh chord, but it’s up a half step. That would be known as a C sharp diminished seventh chord or the E diminished seventh chord, or the G diminished seventh chord or the B flat diminished seventh chord because every single note of a diminished seventh chord can function as a root.

Let’s move up another half step. That’s still a diminished seventh chord, but this time it’s a D diminished seventh chord or an F diminished seventh chord or an A flat diminished seventh chord or B or C flat diminished seventh chord, right?

Now let’s move up another half step. Does that look familiar? It should because it’s the same chord that we started with except it’s upside down. I just took that C from the bottom and put it on top, you see? That’s the chord we started with, so there’s 4 notes there, 4 our of the 12. Here’s 4 more, that’s 8, and when we get 4 more that’s 12. We’ve exhausted all the possibilities haven’t we?

If we move up another half step, that’s like the original I started with. If we move up another half step, that’s like the second chord we started. If I move up another half step, that’s like the third chord we started, so there’s really only 3 diminished seventh chords. That one, that one, that one, and remember each note of the diminished seventh chord can function as the root.

It could have 4 names, couldn’t it? Each diminished seventh chord. Now, the amazing thing about diminished seventh chords is you can get them to lead most anywhere. Let’s say you’re playing in the key of C. You’re coming along. Now if you go to diminished seventh chord … If you lower any one of those notes, any one, you get a dominant seventh chord. That’s a B seventh chord. Where do dominant seventh chords want to lead? They always want to lead up a 4, don’t they?

If I want to modulate from the key of C to the key of E, I just find the diminished seventh chord, lower the bottom note, and then that modulates to the key of E, doesn’t it? Now we’re in the key of E.

Let’s come back to C. If I get that diminished seventh chord and lower the second note, I’ve got a dominant seventh chord there too. That’s the D dominant seventh chord and that lead to G. If I want to get to G, I can do it that way.

Let’s go back to that original chord. If I lower the third note a half step from F sharp to F, that’s an F seventh chord. Where does the F seventh chord want to go? Up to B flat, right? Let’s come back to the original chord. We’ve lowered all the notes except the top note. If I lower the top note a half step, that’s A flat seventh. An A flat seventh wants to go to D flat.

In other words, I can get to 4 different keys with that one chord, can’t I? Just by lowering 1 of the notes. If I choose the second chord, then I can get up to 4 more keys. For example, if I am playing that chord and lower the bottom a half step, that’s C 7, so that goes to F.

I won’t play any more examples but you get the idea. You lower any note of a diminished seventh chord and that becomes a dominant seventh, and that dominant seventh can be used to move up a fourth.

If you move any note up half a step, you get a minor 6 chord, any note up a half step. I moved that note up a half step and that’s A minor 6. Any note … Let me move the bottom note. Yeah, that’s a minor seventh chord too. Any note up a half step.

If I move any 2 notes up a half step, I get a major 6. I’m moving from the bottom to the top, okay? Let me move the middle 2. That’s a C6, so you move any 2 notes up a half step and you get a major 6.

It’s a cool thing to know. If you move any 2 notes down a half a step, what do you get? You also get a major 6. That’s F major 6. Any 2 notes down half a step. That’s B6.

Just to review, there’s only 3 diminished seventh chords. That one, that one, that one, and each one can function as the root, because there’s only those 4 possibilities. When you move any given note of a diminished seventh chord down a half step, that becomes a dominant seventh, which allows you to modulate to the next key.

I realize this is a little bit advanced, so if you’re not too experiences in piano or music, don’t feel bad. It’s maybe ne
w material for you, but think about it and you’ll assimilate it in due time.

If you move any 1 note down you get a dominant seventh chord. If you move any note up a half step, you get a minor 6. If you move any 2 notes up a half step, you get a major 6. If you tune those down a half step, you also get a major 6. You can go most anywhere with a diminished seventh chord. It’s like a doorway to anywhere you want to go.

That’s it for today. Thanks for being with me. If you enjoy these piano tips, come on over to PlayPiano.com and sign up for our free newsletter. Piano tips, I think you’re going to love it, so hope to see you there. Bye bye for now.

Here is an article in Wikipedia on Diminished 7th chords: http://en.wikipedia.org/wiki/Diminished_seventh_chord

Here is the video on YouTube: https://www.youtube.com/watch?v=Q8hkrdE_JxM&feature=youtu.be
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