You hear it all the time … major-thirds have all the fun. But minor-sixths get the cold shoulder!!
Okay, maybe you don’t hear that all the time. (Unless you hang out exclusively with mega-music nerds.) But if you step back and think about it, that’s a really good question. Why does the interval of a minor-sixth get less play than its cousin, the major-third? After all, both of these notes are spaced at equal intervals from the tonic note of a key.
In the key of C, for example, the major-third (E) and minor-sixth (Ab) are both spaced at two whole-tone intervals from the tonic. The E note is just below the subdominant (F), while Ab is just above the dominant (G).
Yet the major-third (E) is honored with much more of a presence in the key of C … while the minor-sixth (Ab) hardly shows up at all.
Well, this has to do with the consonance and dissonance of each note. And how good each pitch sounds when paired with the tonic. Or, better said, how nicely each note plays with the other pitches in key.
E (M3) sounds great when paired with both C (1) and G (5) in a major chord … and that’s important. Because it means the major-third is friends with both the tonic and its dominant – which are, decidedly, the most powerful kids on the block in a given key. So M3 is naturally favored in the songs of that key.
Ab (m6), on the other hand, sounds good with C (1), but downright crummy with G (5). And, as a result, it doesn’t get invited to as many musical parties when C is the host/tonic. (It’s all about who’s friends with who, you know?)
As you might expect by now, it’s easy to see this pattern of major-thirds and minor-sixths in every key. Take a minute to soak it in – noting the fascinating symmetry of pitches in the chromatic scale.
In total, the chromatic scale has four groups of major-thirds or major-sixths. There are two groups of squares and two groups of circles. The squares include all of the primary colors and secondary colors … while the circles include all of the tertiary colors.
Oh yeah, and each note connects with its major-third in a clockwise direction and with its minor-sixth in a counterclockwise direction. So, so cool, my friends. If you get a lay of the land by understanding these patterns, you’ll advance very quickly in your mastery of music theory and its use in the art of writing songs.