In this week's post, we will look at the 12 half steps that make up modern music. And we'll answer this question: Why does the popular worship song "Revelation Song" have such a unique sound?
A Brief History
Almost anywhere in the world, when men and women sing "Happy Birthday" together, they will instinctively and subconsciously gravitate towards singing in octaves, the 2:1 relationship, no matter their musical heritage. This may seem obvious to us now, but in ancient times, there was no music theory. The scales and tunings we use now did not exist. There was no Boss TU-3 Chromatic Tuner for King David's lyre.
hile we know little about the musical systems in King David's time, we do know roughly 500 years later in ancient Greece, guys like Pythagoras started experimenting with vibrating strings. These scientists made interesting discoveries:
A division of the string at the mid-point raised the pitch of each half to an octave above that of the full length, and they took this ratio of 2:1 as the most basic relationship in musical acoustics. A division at a point two thirds of the way along the string's length raised the pitch a fifth, and at three quarters a fourth. Smaller intervals were derived on the same principles, so that the octave could eventually be marked out into tones and semitones. (The New Oxford Companion to Music)
n western music today we break down the octave into 12 equal semitones (notes). This is called the equal temperament system. It is complicated to explain why, but the short answer is the math works out best with it's broken into 12 notes. You can read a detailed article on the 12-tone scale here.
Whole Steps and Half Steps
The distance between each of the 12 tones in an octave is referred to as a half step or semitone. On a guitar, each fret represents a half step, On the piano, each successive key, white or black, is a half step.
Two half steps equal a whole step. For example, C to D on the keyboard is a whole step, while E to F is a half step.
Generally, not all 12 tones are used at one time. Modern music is broken down further into scales.
Scales are the systematic arrangement of half steps and whole steps. Like a painter chooses a color palette, so a composer will choose a scale.
Listen to the audio example as I play through the color palettes listed below:
1. C major (7)
2. C harmonic minor (7)
3. C dorian (7)
4. C whole-tone (5)
5. C minor pentatonic (5)
6. C mixolydian (7)
7. C major (7)
You do not need to know all of these scales to play modern styles of music. This demo is to highlight the colors you can create.
These colors are created by how you combine whole steps and half steps. We'll dig deeper into scales in a later post.
There is more on this topic of semitones and scales, including how to write and read notes at musictheory.ne. (These lessons take just a few minutes to go through. You really should check them out.)
- Learn about how the 12 tones of the octave are written in music.
- Learn more about half steps and how they are notated with accidental.
Next week we will start looking at the horizontal axis of music – rhythm. Tones, semitones, and scales are important, but ultimately it doesn't matter what pitches you play if they don't feel goo in time.
I leave you with a bit of trivia. Ever notice how the popular worship song "Revelation Song" has a unique, almost mysterious sound? f you've played it, you may have noticed the chord progression is not typical. It is in D, but you play an A minor chord in place of an A major chord. This is because the song is based on the D mixolydian scale, not the D major scale*.
*Most song writers aren't thinking in terms of scales when they write. I seriously doubt Jennie Lee Riddle was thinking about mixolydian scales when she wrote "Revelation Song". Similarly, few musicians are thinking "mixolydian" when they play the song. Understanding the basis of the tonality makes you better, but is not a requirement.