… use a minor scale as a melody.
This one surprises me. With the almost infinite possibilities at your disposal, why would you use the minor scale as your melody? I wouldn’t believe it if I hadn’t heard it with my own ears, but this sin has indeed been committed. Maybe it’s been a rough week. The inspiration’s not there? Writer’s block is rearing its ugly head? Well, there’s no excuse for this. Except maybe one: You’re shipwrecked on an island with your piano and the island’s inhabitants have never heard Western music. Then , sure, whip out the minor scale and wow them all.
But for the rest of us, the good book demands you go for something a little more original. And no, using the first 7 notes of the minor scale, then slipping in the major 7th degree before getting to the octave still accounts as a definite no-no. Oh, how many movie trailers have used that one?
Like many other melodic no-no’s, changing the harmony under the melody does not give you the right to use a forbidden melody. It is still too noticeable as a compositional disaster. In fact, if you find yourself using even the first 4 notes in sequence of the minor scale, go back to the drawing board. The first 3 notes is even pushing it. Reach down deep and give us something fresh.