Lesson 18 – Blues Changes (DVD 4)
At this point in the course you've pretty much learned “the rules.” And now we're going to look at a few ways that those rules are commonly broken, and how to work with those rules.
As a guitar soloist – when in doubt, grab those pentatonic scales that go with the chord. Remember that they will always work and are a great fallback position to take when chord progressions get weird.
Blues is such a common thread in all modern music that it's important to understand that, in general, very little of our traditional music theory applies.
Right from the start, blues usually consists of 3 chords (the I, IV, and V of the key) and they are all dominant 7th forms.
And as you already know, you can only have one dominant 7th chord in a song, it's the V chord.
So when you're soloing, you can treat the blues as 3 different keys, and play a different scale with every chord as it goes by. But most people don't do that most of the time. We'll cover some options in a minute.
First, I want to explain what makes blues... “bluesy.” And the simple answer is the flatted 3rd against a major chord (or dominant 7th, which is also major with an added b7.)
You can make anything sound bluesy by throwing a minor pentatonic scale over a major chord, as long as the chord doesn't have a major 7th (that will clash badly... dominant 7th is fine.)
In case you forgot, the minor pentatonic scale formula is 1, b3, 4, 5, b7. So 3 of the notes in a dominant 7th chord are there, but the 3rd is flatted when it should be natural. That's the sound of the blues right there.
Another “blue” note is the flatted 5th tone. In fact, the minor blues scale is the minor pentatonic scale with the addition of that b5. So it's 1, b3, 4, b5, 5, b7.
There's also a major pentatonic scale, which is 1, 2, 3, 5, 6. And the blues version has... you guessed it... the b3 again. So it's 1, 2, b3, 3, 5, 6.
You can also take a mixolydian scale (which always goes well with a 7th chord) and add in some “blues” by adding the b3 and the b5.
That actually creates a pretty substantial conglomeration of notes: 1, 2, b3, 3, 4, b5, 5, 6, b7
That's 9 out of 12 possible notes... most of the fretboard!
In fact, another common approach to blues is to combine together the major and the minor blues scales and when you do that, you get the exact same set of notes as adding the “blues” notes to the mixolydian scale.
So which approach is right? The one that you can remember! It's all about what you can use. So if you can remember blues scales better, then go with it.