More on the Major Seventh Chord
As we did last month with the II chord, we will take a look at some alternatives for improvising over the Major seventh chord. The Major Seventh chord is not always a I chord. In fact, improvisers will use the scale the chord is the IV of as an alternative to this kind of thinking, even if the Major Seventh chord is a I chord. You must always figure out the function of a chord in a chord progression in order to pick the appropriate scale.
As an example, we will use the Dbmaj7 chord. The first task is to determine what key this is the IV chord of. An easy way to do this is to go up a perfect fifth, which gives us an Ab, so our scale of choice here will be an Ab Major scale. The next step is to see how this scale relates to a Dbmaj7 chord. The notes of our scale would be:
Ab - Bb - C - Db - Eb - F - G
Now look at each note and see how it relates to the Dbmaj7 chord. The Ab is the fifth of the chord, the Bb the sixth, C is the seventh, Db the root, Eb the ninth, F the third, and G is the flatted fifth. Other than the G everything fits just fine, with the G giving a little tension to the line that you would be playing.
You can get a little more daring and try the Harmonic Minor scale that the Major Seventh chord is the sixth of. For example, the A Harmonic Minor scale is:
A - B - C - D - E - F - G#
Your sixth note here is F, so you would use the A Harmonic Minor scale over an Fmaj7 chord. Next, as we did above, see how the notes of this scale relate to the Fmaj7 chord. In this case, the A is the third, B is the flatted fifth, C is the fifth, D is the sixth, E is the seventh, F the root, and G# the sharped ninth. Here we have two "outside" notes, so we have to be more careful where we use this kind of thinking.
How about the Melodic Minor scale.? Take the example of a C Melodic Minor scale:
C - D - Eb - F - G - A - B
When you harmonize the Melodic Minor scale you end up with a Major Seventh chord with a sharped fifth as the III chord. For the above scale, this would be an Ebmaj7#5 chord. Analyzing all of the scale against the chord gives us C as the sixth, D as the seventh, Eb as the root, F as the ninth, G as the third, A as the flatted fifth, and B as the sharped fifth. This will be even more of an "outside" sound.
From these examples you can see that you can play a line with varying degrees of tension, rather than being limited to the usual safe choices. You will always have to let your ear be your guide as to where such choices are appropriate. Nevertheless, by being aware of your choices, you will be able to create much more interesting and exciting lines, with whatever level of tension you desire. The point is to try these kind of ideas out to see how they sound so that you can then put them into your playing. There is no better way to create your own identifiable sound than by looking for more ways to build your lines. By practicing these kinds of ideas, you will train your ear to hear lines that you would otherwise not have thought of.