Why Is Harmony Important?
Harmony plays an extremely important role in creating the mood for a piece of music. Changing the harmony of a song can completely change the mood, even if the melody and the rhythms stay the same. Harmony can make a happy melody sad, and a sad melody happy.
The mysterious thing about harmony is that the human brain seems to add harmony to songs even if the harmony isn’t being played. To some extent, this is because a melody can imply harmony, meaning that the notes in the melody suggest which notes and chords would harmonize well with the melody. But this isn’t an exact science. Some melodies can imply one kind of harmony to one person, and a different kind to another.
Some melodies have many logical options for harmony, and if no harmony has been added, you will likely unconsciously “hear” a harmony, even if you are not a trained musician. To illustrate, I could add harmony to “Twinkle Twinkle Little Star,” and even if you’ve never heard this harmony before, it would sound “right” to you. I could then change the harmony a little, and it would sound “wrong.” Or if not wrong, it would sound unusual and interesting. Why does one set of harmony sound “right” and the other sound “wrong”? It’s because the harmony that sounds “right” is the harmony that you unconsciously attach to this song when you hear it without harmony (see chapter 12 where I play out this experiment in full).
I’m reminded of an experience my dad had with a songwriter he was working with. The songwriter didn’t know anything about music theory or harmony, so she asked my dad, a trained musician, to help her record some songs. All she had was a melody and lyrics, and she wanted my dad to add harmony. Using his highly fluent knowledge of music, my dad chose chords that sounded good with the melody, but sometimes the songwriter said that a chord sounded wrong. When this happened he would change the chord until she said it sounded right. So, even though she didn’t know anything about harmony, and she only had a melody, she still had a strong sense of what the harmony should be. She had unconsciously added harmony to her melodies, but she couldn’t identify what she was hearing. I hope that reading these harmony chapters will help you identify the harmony that you hear in your head.