The most common type of 7th chord in everyday use, particularly in pop, rock, folk and blues, is the ‘dominant 7th’, although the word ‘dominant’ is usually omitted. The chord consists of a major triad plus a minor seventh note. It has a more edgy, urgent tone than the simple major triad.
I set myself a challenge:
How many different dominant 7th chords could I cram into a single track?
Here’s the result. It’s called Rocky Road:
So, how many 7ths did I manage to find a home for? The answer is 11 out of a possible 12. I just couldn’t find somewhere to put an F#7.
The verse goes like this: D7 G7 C7 F7 D7 G7 C7 A7 / D7 G7 C7 F7 Bb7 Eb7 C7
And the bridge: G7 C7 A7 D7 B7 E7 A7 Ab7 / G7 C7 A7 D7 B7 A7 D7 G7 C7 A7
I closed on an Fm, just to be different.
You might have noticed that, in the verse, the chord progression descends in 5ths (that’s four notes down the scale from the root of the chord). For example:
D7 down to G7
G7 down to C7
C7 down to F7
F7 down to Bb7
Bb7 down to Eb7
Whereas, in the bridge, the chords ascend in 6ths and 4ths:
G7 up a 4th to C7
C7 up a 6th to A7
A7 up a 4th to D7
D7 up a 6th to B7
B7 up a 4th to E7
And so sometimes it seems that music is just mathematical patterns in sound.