Hiya, hope you’re all well and that your summer has been fantastic. This time around I’d like to cover a harmonic device which we haven’t looked at before, that of secondary dominants.
The term secondary kind of refers to every chord but the dominant chord, now this might seem odd, but lets have a look at a harmonised C major scale.
C – E – G – B C major 7
D – F – A – C D minor 7
E – G – B – D E minor 7
F – A – C – E F major 7
G – B – D – F G dominant 7
A – C – E – G A minor 7
B – D – F – A B minor 7 b 5
As you can see, there’s only 1 dominant chord in each major scale, which sits on the 5th degree of the scale. The thinking behind secondary dominants is to consider each degree of the scale a dominant chord taking into account where it would resolve to ( it’s respective I chord).
C – E – G – Bb C dominant 7 V of F ( IV *)
D – F# – A – C D dominant 7 V of G (V *)
E – G# – B – D E dominant 7 V of A (iv *)
F – A – C – Eb F dominant 7 V of Bb (biiv *)
G – B – D – F G dominant 7 V of C ( I *)
A – C# – E – G A dominant 7 V of D ( ii *)
B – D #– F# – A B dominant 7 V of E ( iii *)
* in C
Now, all of what we’ve just worked out was using C as our root note, but as you can see, using secondary dominant chords brings in notes which are outside of this tonality. In a way, secondary dominants can be thought of as mini modulations, kind of temporary stop offs in a new I chord.
Compare the secondary dominants in the following progression, a simple I – IV in C major
without a secondary dominant
| C ma7 | F ma7 |
with a secondary dominant
| C ma7 C7 | F ma7 |
I ( V of IV )
Notice how the C7 add’s an extra bit of momentum towards the F major 7 in what would otherwise be an entirely diatonic progression, using the secondary dominant (C7) can give you the chromatically descending B ( C major 7th’s major 7th ) Bb ( C7 th’s flat 7th ) and A ( F major 7ths major 3rd ).
Let’s try a chord progression which is in no way diatonic, here I’ve taken a diminished arpeggio and added major 7th chords to each note.
| Ama 9 | Cma9 | Ebma7 | F#ma 9 |
now let’s add secondary dominants
| Ama 9 G13 | Cma9 Bb13 | Ebma7 C#7 | F#ma 9 |
( V I ) ( V I ) ( V I )
The secondary dominants go along way to making the chord progression ‘flow’ because of the V – I resolutions which are heard throughout.
This week was a bit of a taster of secondary dominants, we’ll do some more soon, give them a whirl and see where they lead you. Enjoy!!