Hi GMC'ers! With this lesson I will show how to play different scales over the same chord. You can choose the scale analyzing the chord progression to see if there is a scale which fits well two or more chords. Otherwise, if you have a vamp with a single chord like the backing for this lesson, you can just follow your own personal taste.
To fully understand all the concepts, it is important to master the previous lessons of the series, especially Jazz Notes 3: Modes Workout
and Jazz Notes 12: Diatonic Improvisation
I chose to play over a Bb7 chord because dominant 7th chords can support a great variety of extensions. As guitarists, we usually tend to play while jamming over the same scales, tipically E or A minor pentatonics. Playing over a Bb7 chord is usually a good challenge.
Let's start with the first scale, Bb Mixolydian, which is the 5th mode of the Eb Major scale. This scale is quite easy to use and improvise with. Just be careful while using the 4th degree - in this case the Eb note - because it sounds a little dissonant. You can play it as a passing note with no problem at all.
Let's take a look at the second scale. Bb Lydian b7 is the 4th mode of the F melodic minor scale. It has a raised 4th, in this case a natural E note. This note is the only difference between this scale and the previous one, the mixolydian. If you consider the raised 4th as a tension you get a new chord, usually written Bb7#11 or Bb7#4. Remember that 4th and 11th are the same notes, just in different octaves. So this scale is a great choice over X7#11 chord or you can just play it over dominant 7th chords to get the flavour of the #11.
The Blues scale is quite easy to use to improvise. It's also usually one of the first scales we learn as guitarists. We just need to discuss some facts. The Blues scale has a minor 3rd while the dominant 7th chord has a major 3rd. This is not a big problem because one of the reason about the "bluesy" sound of this scale is the minor 3rd played against a major 3rd on the chord. Then we have a lowered 5th - or a raised 4th - which gives a characteristic sound to the scale. On the following diagram is the one with the green color. This is usually used as a passing note.
The Bb super locrian scale is the 7th mode of the Cb melodic minor scale. Sometimes this scale is also called the "altered" scale because it fits very well the altered dominant 7th chord. This particular chord has all the possible alterations together in the same chord. In particular it's possible to alter the 9th degree, lowering and raising it at the same time. It's possible to raise the 4th (same as 11th) and lower the 6th (same as 13). You can't lower the 4th because you get a major 3rd and you can't raise the 6th because you get a minor 7th.
So, the complete chord symbol could be something as Bb7b9#9#11b13... It's not very easy to read and understand!! A common way to write this chord is Bb7alt. This scale is commonly used in Jazz while it's quite difficult to find it in other styles. The dominant 7th chord has a strong sound itself and you can try to use this scale even if it's not an altered chord. Listen carefully how each notes sound against the chord so you can use it in the right way when it's needed!
As exercise, try to extend these scale diagrams to all the fretboard, finding new fingerings and licks!