Using Dominants – Part 2

In this new, 5 part series we’ll be looking at the importance of the dominant 7th chord and some of the more unusual places that you can use them. In part 2, we’ll be looking at how to use a dominant 7th on chord 1:

 

 

Last week, we looked at the basic function of a dominant 7th chord. The dominant 7th is usually associated with chord V as it takes us back to the tonic. Over the next few weeks, we’re going to explore other places that we can use the dominant 7th and the different places it can take us harmonically. This week, we are going to be using the dominant 7th on the tonic.
Let’s take the classic, popularised hymn, Amazing Grace:
A                              D              A                                               E      E7
Amazing grace how sweet the sound that saved a wretch like me
A                           D           A                              E        A
I once was lost but now I’m found, was blind but now I see
This a very basic chord progression, using chords I, IV and V. We’ve got a dominant 7th on chord V (E), which takes us nicely back to chord I. We’re now going to put a dominant 7th on chord I, the tonic and create a cheeky little perfect cadence. A (chord I) will become A7, so it will temporarily act as a chord V, pulling us to the chord a fifth below, which will be D, temporarily chord I:
(V    -    I)
A              A7        D            A                              E        A
I once was lost but now I’m found, was blind but now I see
Listen to how it alters the sound. We’ve not moved away from the key of A major, but we’ve helped create a stronger pull to chord IV, D.
Finally, let’s look at how we can use a dominant 7th on the tonic to smoothly change key.
The clearest way to change key is with a perfect cadence going into the new key. One thing that really helps the key change sound smooth, or even better, unnoticeable, is by overlapping using some chords that fit into both keys. Let’s take a look:
Key of A major:    I    IV    V    I      I7    IV    ii
A    D    E    A    A7    D    Bm    Em    A7    D
Key of D major:                             V      I     vi        ii       V      I
By doing this, it becomes slightly unclear to the listener where the key change has happened. It’s not until the Em that a chord appears that doesn’t fit into both keys, but by that point we’ve been in D major for while. Here’s another example:
Key of A major:    I    IV    V    I      I7    IV    vi
A    D    E    A    A7    D    F#m     G      A7    D
Key of D major:                             V      I     iii         IV      V      I
The important thing is that you do eventually make a clean break into the new key. If you only use chords that fit within both keys then you won’t have properly changed keys.

 

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