Dominant 7th Push: Circle of Fifths Theory Lesson

A 7th chord on the ukulele almost always leads somewhere. It pulls your ear and is used as a musical signal.

By nature, 7th chords are unresolved. They are twitchy and in a state of limbo. This limbo is called tension. All music needs some sort of tension and resolution for it to have movement. The resolution part happens when you move from tension to not-tension. It’s a moment of sonic release when you feel like you’ve arrived “home.”

There are several signpost chord changes that can help steer a song along, but this one is a LAS! VEGAS! NEON! SIGNPOST! compared to the street sign on the corner.

It can be used by musicians to signal one another or just to point the listener’s ear in the right direction. This is called the I7 chord (pronounced “one-seven”).

Unless you are playing blues it almost always resolves to the IV (four) chord. With this knowledge you can create lead-ins to certain chords in a song or signal lost band members where you are going. It sounds pro.

Our special signpost – I7 – is made up of a Roman numeral (I – or 1) and the chord type (7th). You can write out any chord progression with these numbers. It’s great because it removes any note names from the equation and only tells you the relationship between chords. If you go from a I chord to a V chord it will always be the same distance and relative sound no matter what key you are in.

So let’s figure out what those Roman numerals stand for. It basically is the equivalent to our normal Arabic numbers. I II III IV V is the same as 1 2 3 4 5. You can use either to the same effect. I learned this system with the numerals so that’s what I use, but you will see both. Each number represents a note in a 7-step scale. The numbers count up to 7 and then start over again (sometimes you see 8 at the top, but it’s the same as 1). You just go up a number every time you go up a note. Like this with a C scale:

C   D   E   F   G   A   B   C

So if I said “play the IV in the key of C,” you would play F. If I said “play the VI in the key of C,” you would play A. Simple enough, right?

Okay. Now remember that the reason we use numbers is so that this works easily in any key. That means you could make a number line such as above using the scales from every key and end up with 12 different I chords, 12 different IV chords, and 12 different V chords, not to mention the rest. Still sounding simple? Good.

With all that said, let’s look at how it relates to our I7 to IV progression. We’ll work in the key of C for simplicity.

Let’s find the I7 first. Make a scale row with the numbers and highlight the number we are looking for:

C   D   E   F   G   A   B

Now you just take the I – C in this case – and plop a 7th on the end of it to match the chord type of the Roman numeral – C7. I7 is the same as C7 in the key of C.

Do the same process for the IV and you get F. Like this:

C   D   E   F   G   A   B

But this time there is no chord type to apply so it stays just a plain F chord.

C7 leads to F in the key of C. Try it out. Play C then C7 then F. Magical, right? Now play C to C7 and go to a chord besides F like G7. It’s not the same. There’s no magic beanstalk there to lead us somewhere special. For some reason the I7 to IV push sounds good.

Try another key – E this time just to make it hard.

We know that the I is the name of the key so without even having to think we can come up with E7 as the I7. What about the IV? Count up:

E   F#  G#  A   B   C#  D#

The I7 to IV in the key of E is E7 to A.

In G?

G   A   B   C   D   E   F#

G to G7 to C.

Try a couple out yourself. If you need a sheet with the scale notes, go here: Theory Reference Sheet

This is a very common movement in Hawaiian music and only a little less so in most other genres. If you go back into your songbooks I bet you’ll find places where you are playing this progression without even knowing it.

Using what you now know, try and find some places in your songs where you could add in a I7 to push to the IV. Pretty much anywhere a song goes from I to IV could work, but it usually sounds best when you have a little bit of lead up time to the IV. I’d say 4 beats at the least on the I chord.

What you can do is cut the time you are on the I chord in half and make one side I and the other I7. That way you have time to get established on the root, feel the expectant movement to the I7, and then the resolve up to the IV.

Continuing the Push:

There are a lot of songs that use this push technique in a much more blatant way. They use the 7th to push to another chord, but that chord is a 7th as well so you have to keep moving (sometimes this just keeps happening so you have a big long string of 7th chords)! A Hawaiian vamp is a great example of this continuing variation on the I7 push. The formula for a Hawaiian vamp (or “turnaround”) is II7 V7 I.

In C you get this:

C   D7  E   F   G7  A   B

You’re probably thinking, “What does this have to do with the I7!?” Nothing if we look at it in C like this. But if we start it with the first chord from the vamp (D7) as our root:

D7  E   F#  G   A   B   C#

See it now? G is IV chord in the key of D. So all you have to do is put the first 7th chord you play as the root and the next chord is always the IV. Continuing on…

G7  A   B   C   D   E   F#

That’s a Hawaiian vamp. D7 leads to its IV – G. G7 leads to its IV – C.

Now then. You could continue to cycle around with 7ths leading into fourths as long as you wanted. Eventually you would come back to where you started after visiting all twelve 7th chords (something to try out sometime – *hint, hint*).

Five Foot Two Eyes of Blue is a fairly typical example of a string of 7th chords that lasts even longer than the Hawaiian vamp. The progression goes: C E7 A7 D7 G7 C. Do the counting yourself and you will find that once you hit the first 7th chord, all the rest are a fourth away.

This can get you out of trouble if you are jamming away on a tune you don’t know and all of a sudden everyone changes to a 7th chord that is out of key. If you realize it as a signpost, you will see that it almost always points the way to a fourth above. Just keep cycling around until you get back home.

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