Music theorists have worked for hundreds of years on what constitutes harmonious music. This theory helps explain why smashing your fists on a piano will not sound nice, but pressing the black keys in any given order will.
They discovered that we can group note-relationships into different scales. Our culture determines the way we perceive those scales. Western culture perceives the Minor-scale as sad and Major-scale happy. Rampant overuse of the Double harmonic scale in movie-scores for scenes that are set in the middle-east, has turned it foreign and scary. Likewise, a movie about feudal Japan is not complete without a Hirajoshi Scale.
So what happens if we change a song’s key rewrite a song from one scale to another? If we change a song’s key from major to minor, does it become sad? Kinda. Unfortunately there is no algorithm we can apply to change a songs key without creating disharmony that breaks the music theorists rules for what constitutes harmonious music. We are forced to change some notes to make it abide by these laws. The resulting music tends to adopt the qualities of whatever scale you rewrote it in. A song rewritten to the minor key becomes sad and vice-versa.
There is another algorithm we can consistently apply to any harmony which does not result in any broken rules. An explanation of the algorithm can be found here.
If the original music was harmonious, the negative harmony will always be as well. But weirdly enough, it never sounds as good. Why is that? What is the quality that the original harmony possessed, which its negative harmony does not?
To give an example of this, Stairway to heaven’s negative harmony, is bland and forgettable, whereas the original is widely regarded as one of the best pieces of music ever written. What changed that made the song lose its beauty?
Wherein lies the magic that makes a song go from merely harmonious, to beautiful?