Music Lessons

[Spood]

Yay! More!!!

Oooh 12-Bar-Blues, we did that in music this year, I think we do some more in elective next year.

Singing... hmm....

-Spfd

[Marty]

Oooh 12-Bar-Blues, we did that in music this year, I think we do some more in elective next year.

Don't worry; I'll be going FAR past what you'll have learnt, most likely...there's a lot happening there and how to play over it...

[Marty]

The 12-Bar Blues

Finally, I get around to doing the promised piece on the twelve-bar blues. This is going to cover everything from the simplest blues to the Jazz blues, which gets a wee bit more complicated. Much as the history of blues is fascinating, it’s kinda irrelevant for the actual playing of it.

The most important chord in a blues sequence is the Dominant Seventh chord, which we saw last lesson as being spelt 1-3-5-b7 (eg C-E-G-Bb). In the 12-Bar Blues, the most common type of blues and the one we’re looking at, this chord is used EVERYWHERE. The 12-Bar Blues in C goes like this:

C⁷ | C⁷ | C⁷ | C⁷|
F⁷ | F⁷ | C⁷ | C⁷|
G⁷ | F⁷ | C⁷ | C⁷|

What we have here is the basic sequence. It has the home chord (C⁷) for four bars, then the fourth (F⁷) for two bars, then back to the home (C⁷) for another two bars, then the fifth (G⁷) for a bar, then the fourth for a bar (F⁷), then the home (C⁷) for another two bars.

A key point in the Blues is called the Turnaround. This is a way of bringing the sequence back to the home chord – in our example, this is C⁷. The most common way of bringing a sequence back to the home chord is by going to the fifth (G⁷) and then back. If you have an instrument, play this – you can hear that it sounds finished. If we add this at the end of our sequence, we get…

C⁷ | C⁷ | C⁷ | C⁷|
F⁷ | F⁷ | C⁷ | C⁷|
G⁷ | F⁷ | C⁷ | G⁷|

Or written in roman numerals, like this…

I⁷ | I⁷ | I⁷ | I⁷|
IV⁷ | IV⁷ | I⁷ | I⁷|
V⁷ | IV⁷ | I⁷ | V⁷|

Looking again at that chord sequence, let’s see what is actually happening here in terms of notes. We don’t need to bother about how many bars for this, it’s just the notes we’re looking at.

C⁷ – C-E-G-Bb
F⁷ – F-A-C-Eb
C⁷ – C-E-G-Bb
G⁷ – G-B-D-F
F⁷ – F-A-C-Eb
C⁷ – C-E-G-Bb
G⁷ – G-B-D-F

The most important notes in a chord are the third and seventh (in C7 these are E and Bb) because they define whether the chord is major (1-3-5-7), minor (1-b3-5-b7) or dominant (1-3-5-b7). So let’s just look at those notes…

C⁷ – E-Bb
F⁷ – A-Eb
C⁷ –E- Bb
G⁷ – B-F
F⁷ – A-Eb
C⁷ – E-Bb
G⁷ – B-F

If you look carefully, there’s not much movement there – only semitones (eg Bb to A in C⁷ to F⁷). So the whole sound of the blues sequence can be played using just six notes that are right next to each other – Eb, E, F and A, Bb, B. an if you just use those notes, you can get the sound of the blues sequence – try it.

As the blues has been played for more than 100 years, you can’t expect people to just use those simple movements all the time. So people have added to it and changed bits so that it’s more interesting. The first, very simple change is to add an F⁷ in the second bar to give this…

C⁷ | F⁷ | C⁷ | C⁷|
F⁷ | F⁷ | C⁷ | C⁷|
G⁷ | F⁷ | C⁷ | G⁷|

Or written in roman numerals, like this…

I⁷ | IV⁷ | I⁷ | I⁷|
IV⁷ | IV⁷ | I⁷ | I⁷|
V⁷ | IV⁷ | I⁷ | V⁷|

This breaks up the four solid bars of C⁷. The next change is more Jazz-influenced. The most common chord sequence in Jazz is the ii-V-I (eg Dm⁷ G⁷ Cmaj⁷), so they added this in bars 8 through 10 to give this…

C⁷ | F⁷ | C⁷ | C⁷|
F⁷ | F⁷ | C⁷ | A⁷|
Dm⁷ | G⁷ | C⁷ | G⁷|

Or written in roman numerals, like this…

I⁷ | IV⁷ | I⁷ | I⁷|
IV⁷ | IV⁷ | I⁷ | VI⁷|
IIm⁷ | V⁷ | I⁷ | V⁷|

Notice that there is also a turnaround (V-I) in bars 8 and 9, making this a IV-ii-V-I really. This sounds complicated, but it’s just treating the ‘ii’ (Dm⁷) as a ‘I’ and therefore doing a turnaround onto it.

The next variation adds even more movement into the sequence, with (Shock! Horror!) more than two chords in a single bar at times.

C⁷ | F⁷ | C⁷ | Gm⁷ C⁷|
F⁷ | F⁷ | C⁷ | Em^7b5 A⁷|
Dm⁷ | G⁷ | C⁷ A⁷ | Dm⁷ G⁷|

Or written in roman numerals, like this…

I⁷ | IV⁷ | I⁷ | IIm⁷ V⁷|
IV⁷ | IV⁷ | I⁷ | IIm^7b5 VI⁷|
IIm⁷ | V⁷ | I⁷ VI⁷ | | IIm⁷ V⁷|

Remember that Em^7b5 chord from last lesson? It’s spelt 1-b3-b5-b7, or E-G-Bb-D.

This is adding a lot of what is called ‘Diatonic Harmony’. Those are scary words! What it means is that, although in the strictest sense the blues sequence has no key, we are adding harmony as if there were keys at some points. For example, bar 8 treats the key as D, and bars 9-12 treat the key as C, whereas bar 4 treats the key as F. Diatonic just means ‘belonging to the key’.

The next variation gets EVEN MORE complicated. It adds a diminished chord (shown by the symbol º) in bar 6 as well as adding more of that crazy Diatonic Movement, as well as some even crazier Chromatic Movement.

C⁷ | F⁷ | C⁷ | Gm⁷ C⁷|
F⁷ | F#^º | C⁷ Dm⁷ | Em⁷ Ebm⁷|
Dm⁷ | G⁷ | C⁷ A⁷ | Dm⁷ G⁷|

Or written in roman numerals, like this…

I⁷ | IV⁷ | I⁷ | IIm⁷ V⁷|
IV⁷ | IV# ^º | I⁷ Iim⁷ | IIIm⁷ IIIbm⁷|
IIm⁷ | V⁷ | I⁷ VI⁷ | | IIm⁷ V⁷|

The Diminished Chord is Spelt 1-b3-b5-bb7 which from F# gives F#-A-C-Eb. If we look at the chord it’s replacing (F⁷) you get F-A-C-Eb, so only one note is being changed – simplicity again.

In bars 7-8 we get some Chromatic Movement. Chromatic means that the gap between each note is a semitone, so here we get D-E-Eb which is just a cluster of semitones next to each other.

The greatest thing about all this movement is that the sound of the Blues Sequence is still there. We’ve gone from…

C⁷ | C⁷ | C⁷ | C⁷|
F⁷ | F⁷ | C⁷ | C⁷|
G⁷ | F⁷ | C⁷ | C⁷|

…to…

C⁷ | F⁷ | C⁷ | Gm⁷ C⁷|
F⁷ | F#^º | C⁷ Dm⁷ | Em⁷ Ebm⁷|
Dm⁷ | G⁷ | C⁷ A⁷ | Dm⁷ G⁷|

…and it still preserves the basic sound, and so can be played over in much the same way. And that is what I’ll be showing you next time. See you then!