• Scale Formation: Casting Out The Devil In Music

    in Piano,Scales

    Today, we’ll be casting out the devil in music.

    In medieval times (400AD – 1400AD), the intervals of an augmented fourth or a diminished fifth were known as diabolus in musica. Translated to English, it means “the devil in music.”

    “What are augmented fourth and diminished fifth intervals?”

    An augmented fourth is larger than the perfect fourth by a semitone (half step). Using the major scale of C:

    …if we make the perfect fourth interval:

    ….larger by a semitone (half step):

    …this will produce the augmented fourth interval:

    A diminished fifth interval is smaller than the perfect fifth interval by a semitone (half step). Using the major scale of C:

    …if we make the perfect fifth interval:

    …smaller by a semitone (half step):

    …this will produce the diminished fifth interval.

    “Why are they called the ‘devil in music?’”

    Perfect intervals sound very pleasant and agreeable. They are described as consonant intervals because they have a sense of repose.

    Making them larger or smaller makes them sound unpleasant (dissonant).

    Augmented fourth vs perfect fourth

    The augmented fourth is dissonant because it is larger than the perfect fourth by a semitone (half step).

    Diminished fifth vs perfect fifth

    In the same vein, the diminished fifth is dissonant because it is smaller than the perfect fifth by a semitone (half step).

    These intervals consist of three adjacent whole tones (aka “whole steps”).

    An augmented fourth in the key of C:

    …consists of three adjacent whole tones:

    C-D:

    D-E:

    E-F#:

    A distance of three tones in Latin means tritone.

    The “devil in music” is popularly known as the tritone. In medieval times, it was forbidden because of its extreme dissonance.

    In today’s post, we’ll be doing a little scale formation exercise by casting out the devil in music.

    I can’t wait anymore, let’s get started!

    Parallel Fourth Intervals

    An interval of a fourth consists of four scale steps.

    In the key of C major, we’ll be looking at fourth intervals from every degree of the major scale. Check them out below:

    Four scale steps from C is F:

    …C, D, E, and F:

    C to F is a perfect fourth.

    Four scale steps from D is G:

    …D, E, F, and G:

    D to G is a perfect fourth.

    Four scale steps from E is A:

    …E, F, G, and A:

    E to A is a perfect fourth.

    Four scale steps from F is B:

    …F, G, A, and B:

    F to B is an augmented fourth.

    Four scale steps from G is C:

    …G, A, B, and C:

    G to C is a perfect fourth.

    Four scale steps from A is D:

    …A, B, C, and D:

    A to D is a perfect fourth.

    Four scale steps from B is E:

    …B, C, D, and E:

    B to E is a perfect fourth.

    Moving in parallel fourths from one degree of the major scale to another will produce perfect fourth intervals, except on the fourth degree of the major scale:

    …where an augmented fifth is formed:

    It is worthy to note that when fourths are played in parallel, the augmented fourth interval (aka – “the devil in music”) is formed between the fourth and seventh tones of the scale:

    F and B.

    Parallel Fifth Intervals

    An interval of a fifth consists of five scale steps.

    We’ll be forming fifth intervals from every degree of the C major scale, just like we did in the last segment. Check them out below:

    Five scale steps from C is G:

    …C, D, E, F, and G:

    C to G is a perfect fifth.

    Five scale steps from D is A:

    …D, E, F, G, and A:

    D to A is a perfect fifth.

    Five scale steps from E is B:

    …E, F, G, A, and B:

    E to B is a perfect fifth.

    Five scale steps from F is C:

    …F, G, A, B and C:

    F to C is a perfect fifth.

    Five scale steps from G is D:

    …G, A, B, C, and D:

    G to D is a perfect fifth.

    Five scale steps from A is E:

    …A, B, C, D, and E:

    A to E is a perfect fifth.

    Five scale steps from B is F:

    …B, C, D, E, and F:

    B to F is a diminished fifth.

    Moving in parallel fifths from one degree of the major scale to another will produce perfect fifth intervals, except on the seventh degree of the major scale:

    …where a diminished fifth is formed:

    When fifths are played in parallel, the diminished fifth interval (aka – “the devil in music”) is formed between the seventh and fourth tones:

    B and F.

    Consider this carefully…

    The augmented fourth and diminished fifth are equal in size, but differ in spelling.

    C augmented fourth interval:

    C diminished fifth interval:

    If you’re familiar with inversion of intervals, you’ll know that the inversion of an augmented fourth will produce a diminished fifth and vice versa.

    In the parallel fourths series, we encountered F-B:

    …an augmented fourth. Inverting it to B-F:

    …will produce the diminished fifth interval we encountered in the parallel fifth series.

    In the major scale of C, the devil in music, whether as an augmented fourth:

    …or diminished fifth:

    …is connected to the fourth and seventh degrees of the major scale (B and F respectively).

    Having said that, let’s get into the segment everyone’s been waiting for.

    Casting Out The Devil In Music

    The fourth and seventh tones in the major scale of C are:

    F:

    …and B:

    …and they are the devil in music:

    If we cast the devil in music out of the major scale, this will produce:

    …a major scale without the fourth and seventh tone.

    Incidentally, this new scale is an already known scale. It is called the major pentatonic scale.

    The term major is used to define this scale because of its relationship to the major scale, while the term pentatonic is used to define scales that have five scale tones per octave.

    3 Facts about this new scale

    The pentatonic scale is a major scale without the devil in music and here are three things I know about the pentatonic scale.

    #1 – It’s very flexible in improvisation. Unlike the major scale, the pentatonic scale can be used over various chord progressions that move in and out of the key. In fact, the pentatonic scale does the job better than the major scale.

    #2 – The pentatonic scale has no avoid notes. In a previous post, we covered the avoid note (which is the fourth tone of the major scale). In the pentatonic scale, there is no avoid note because, as you already know, we casted it out. Lol.

    #3 – It is used in early childhood education. In certain parts of the world, before children are introduced to the major scale, they are exposed to the pentatonic scale. This is because even experienced improvisers can attest to the fact that one can hardly make mistakes while improvising with the pentatonic scale.

    Final Words

    At this point, you should know that the goal of this post is to familiarize you with formation of the pentatonic scale.

    Forgive me if the term “casting out the devil” got you curious and maybe scared.

    My intentions are far from that. I really do hope that with any given major scale, you can derive a pentatonic scale simply by casting out the devil in music (the 4th and 7th tones).

    Until next time.

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    Chuku Onyemachi

    Head of Education at HearandPlay Music Group
    Onyemachi "Onye" Chuku is a Nigerian musicologist, pianist, and author. Inspired by his role model (Jermaine Griggs) who has become his mentor, what he started off as teaching musicians in his Aba-Nigeria neighborhood in April 2005 eventually morphed into an international career that has helped hundreds of thousands of musicians all around the world. Onye lives in Dubai and is currently the Head of Education at HearandPlay Music Group and the music consultant of the Gospel Music Training Center, all in California, USA.



    Tagged as: devil in music, pentatonic scale, tritone


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