Chord Building: Adding the 7th

Let's enjoy the evening and take a look at major 7th chords.

Now we're going to look at adding one more note to the major triad, making it a 4 note chord;therefore, no longer a triad, but a major 7th chord. Here's how we do it -

C, E, G, B (1, 3, 5, 7)

Just by adding another interval of a 3rd on the top, we have built a C major 7th chord. It can be symbolized in two different ways - CM7 or C Maj 7.
We can also invert this chord, just as we did the C major triad:
Root = C, E, G, B
1st inversion = E, G, B, C
2nd inversion = G, B, C, E
3rd inversion = B, C, E, G
We now have three inversions because of the added interval

Let's look at the intervals of these inversions now:
Root = C, E, G, B - this is three 3rds built one upon the other
1st inversion = E, G, B, C - here we have a 3rd (E to G) on the bottom, a 3rd (G to B) in the middle, and an interval of a 2nd (B to C) on the top.
2nd inversion = G, B, C, E = again we have a 3rd (G to B) on the bottom, a 2nd (B to C) in the middle, and a 3rd on the top.
3rd inversion = B, C, E, G - on the bottom, we have an interval of a 2nd (B to C), a 3rd (C to E) in the middle , and a 3rd (E to G) on the top.

Notice that there are no 4ths in the chords because the 7th (scale degree) has been added.

Next time we will look at building a dominant 7th chord.