(TRD) Diatonic Triad Lesson

Diatonic Triads

Every major and minor scale has seven special triads, called diatonic triads, which are formed from that scale's notes. To discover the diatonic triads, a three step process must be used.

First, construct the scale. We will be using the C major scale for our first example.

Next, stack two generic thirds on top of each note. Finally, analyze the resulting triads.

The first triad is C--E--G, a major third and a perfect fifth. Therefore, the triad is major.

The second triad is D--F--A, a minor third and a perfect fifth. Therefore, it is minor.

The third triad is E--G--B, a minor third and a perfect fifth. Therefore, it is also minor.

The fourth triad is F--A--C, a major third and a perfect fifth. Therefore, it is major.

The fifth triad is G--B--D, a major third and a perfect fifth. Therefore, it is also major.

The sixth triad is A--C--E, a minor third and a perfect fifth. Therefore, it is minor.

The seventh triad is B--D--F, a minor third and a diminished fifth. Therefore, it is diminished.

The eighth triad is a repetition of the first (C--E--G), making it major.

The first triad of a major scale will always be major; the second and third triads will always be minor, etc.

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