The diminished as ‘ruler’Modulating and leading with diminished chords

The twelve notes divide into two whole-tone scales and into three diminished seventh chords, and nothing goes beyond those twelve. Barry reminds the class of this as a basic fact to know before working with diminished chords.

Jazz theory, part 2: drop voicings4:58

Everything is minor thirds, Barry says; it is the most important interval of all. The whole-tone scale gives you major thirds, but the diminished chord gives you minor thirds. So the major keys a minor third apart, C, E-flat, F-sharp and A, are brothers and sisters: one family. C major’s family is E-flat, F-sharp and A, and you practise them together.

Jazz theory, part 1, with score4:23

In a class in Bilbao, given through a Spanish interpreter, Barry described the diminished scale as the four notes of the diminished chord combined with the roots of the dominants it relates to. Each diminished note therefore sits between two of those roots: E-flat, for example, is surrounded by D and F. Exercise: from a diminished note, move to a neighbouring note and come back to the original, and do this through every inversion of the diminished chord.

Diminished chords0:331:091:412:18

The first way to modulate, Barry says, is with the diminished chord. He calls the diminished the ruler: you may think you are heading for G, but the diminished can say no and take you to F, B-flat or C instead. One diminished chord can lead you into several different keys.

11 March 2016, part 2: the diminished as ruler2:39

In a B flat blues, run the B flat major scale up and down to the third of G (B natural), then go up the diminished from that note. This falls in bars 7 and 8 and one beat into bar 9. It is a diminished that takes you to the two: the one a half step below the two. Barry said he doesn’t believe in ‘two’ chords, but uses the word because horn players need some harmony to think in.

Practising the blues with the horns, part 11:113:003:36

A second diminished also leads to the two: the one a half step above it. In a B flat blues this is the E diminished (E is a half step above E flat, the four). Run the B flat major scale up to the major seventh and down to the four (E flat). Step up a half step to E concert, run down the E diminished seventh chord, and end on E flat.

Practising the blues with the horns, part 13:364:42

In the blues a horn player can use either diminished whenever he likes, regardless of what the rhythm section plays. Barry finds the upper one, E diminished in B flat, the most interesting: it leads to the two and also back to the one. For example, after the E flat major you can play E diminished to return to B flat. The lower one only takes you to the two. He compared the upper one to being taken up to heaven and brought back down to earth.

Practising the blues with the horns, part 16:3410:2410:57

At that spot in the blues, bass players tend to assume the diminished is always the one a half step below the two. They need to know the one above as well, because both are equally important. In a real old-time slow blues Barry doesn’t like the G7s at all; that style uses the upper diminished instead, and he played it to show how pretty it sounds.

Practising the blues with the horns, part 16:347:43

Then string the devices into one longer blues line, as Barry had the horns do: run up the B flat major scale and down to G, go up the diminished, come down the scale to the seventh of F7, then pivot (as with the diminished: play it up, hit its first note and bring the other notes down). He had them repeat it, then play it over the blues, and next added another diminished on the third of F.

Practising the blues with the horns, part 112:0217:5018:2219:03