Fear The Diminished: Diabolus In Musica


In my previous article "Harmonic Alchemy - Face the Diminished" I discussed the serious side of the Diminished realm and its infamous interval, the b5th. In this article I look at the lighter/darker side of this enigmatic tritone, the so called 'diabolus in musica'.


The Locrians were a pre-christian Greek tribe circa 2000 BC. Back in ancient Greece, the guitar of the day was the 8 string lyre. It was tuned in a variety of combinations known as modes. We know from published writings of Pythagoras' biographer Iamblichus, that each tuning was deployed in order to create a specific emotional response (in the same way as we use our modern modal system). This said though, the 7 modes or inversions of the major scale as they are played today were only arbitrarily assigned their current Greek tribal names in the 16th century, courtesy of a Swiss monk/theorist called Glareanas.

Original Sin

Legend has it that an 11th century Benedictine monk and vocal tutor Guido d'Arezzo coined the dictum 'mi contra fa est diabolus in musica' (translated: 'Mi with FA is the devil in music') to discourage vocalists from using specific dissonant intervals. His students of Gregorian Chant were taught the major scale (e.g. C D E F G A B C) as follows: fa, sol, la, fa, sol, la, mi, fa. In the C scale, Mi is the B (7th) and Fa is the C (Root) or F (4th). Here are the implied 'mi - fa' combinations including inversions: C to B is a 7th. F to B is a #4th. B to C is a b2nd. B to F is a b5th.

Curiously it is only the b5th of these intervals that retains the demonic moniker in modern times.

Modal Malevolonce

The dissonant intervals of the major scale implied by Guido's dictum are the 7th, #4th, b5th, b2 nd.

B Locrian (as we know it) is the seventh mode or inversion if the major scale. In the key of C, the notes B C D E F G A B represent the B Locrian Mode. A dreaded tritone occurs between B and F (mi to fa ascending). Locrian's other ghoulish interval is its b2nd (mi to fa ascending, B to C).

F Lydian is the fourth mode (F G A B C D E F) of C. F to B is a fiendish #4th (or a cunningly disguised b5th). F to E is a sinister 7th.

E Phrygian (E F G A B C D E) is the third mode and produces a hellish b2nd between E and F.

Harmonic / Melodic Minor Scale Malignancy

By raising the seventh note of the A Aeolian mode in C you get the A Harmonic Minor scale (A B C D E F G# A). A to G# is a stygian 7th.

If you develop its modes you will discover that both D Dorian (D E F G# A B C D) and G# Mixolydian (G# A B C D E F G#) have been infected by the forbidden tritone.

G# Mixolydian also produces a demonic b2nd.

Now raise the sixth note of the Harmonic Minor scale to create the A Melodic Minor scale (A B C D E F# G# A). Its C Ionian mode (C D E F# G# A B C) falls prey to 'tritonic' temptation.

The Devil's Work

Here are just a few famous examples I have come across of the #4th /b5th in action.

  • Henry Mancini - Pink Panther Theme
  • Danny Elfman - The Simpsons Theme

I am sure our monk Guido would have been the first to laugh.

Advocatus Diaboli

Giuseppe Tartini, a violin virtuoso, composed the Devil's Trill Sonata in the 18th century. He claimed in a dream that the devil gave him instructions how to play the tune. I found it almost devoid of nefarious dissonance, although the Vanessa Mae version has a wicked laugh at the end. To be fair to Giuseppe though, he later conceded that the tune as we know it was not a patch on the phantasmagorical version of his dream. In modern times there have been bands and composers seeking to scare the meek with discord. Check out the chilly diminished intervals of Black Sabbath - "Black Sabbath" or Jerry Goldsmith's film score of "The Omen". Perhaps it is examples like these that continue to reinforce the b5th 's reputation.

Black Sabbath's dark image curiously at odds with their upward facing crosses.

Pact At The Crossroads

The common Minor Pentatonic scale e.g. A C D E G has also fallen victim to the subtle shenanigans of the fiery one. Enter the ubiquitous Eb (or 'blues note') chromatic note, courtesy of the Minor Blues scale (which is the Minor pentatonic with an added b5th, Eb). This no doubt reinforces the efficacy of the legend of blues luminary Robert Johnson, who is claimed to have met with Satan at the crossroads and signed over his soul to play the blues and gain mastery of the guitar. Interestingly, there are alternative practitioners on the web still seeking to cash in on this short-cut to stardom e.g. Dr. Snake, King Of The Swampland Hoodoos.

Plato And The Taliban

The b5th aside, history reminds us that music and instruments themselves have been the subject of superstition and derision. In the 4th century BC, Plato banned the Aulos (a double flute) from his utopian Republic because the instrument was associated with the 'evil' Dionysian cult. More relevant perhaps are the activities of the Taliban, the now infamous 'musicathropes' (my term describing despisers of music) of Afghanistan. Check out this quote taken from the Guardian (October 13, 2001), "In December 1998 an official notice was placed in a local newspaper in the city of Herat in western Afghanistan. It reported that a 'number of unlawful instruments and goods' had been collected and publicly burned. The inventory included televisions, cassette players and VCRs and thousands of tapes. The list also included 'musical instruments and accessories', items justified by an accompanying hadith [a report of the sayings or actions of the Prophet Mohammed] declaring that 'those who listen to music and songs in this world, on the Day of Judgment molten lead will be poured into their ears'."


I heard an anecdote recently about a music lecturer who refused to demonstrate the Locrian mode to his aspiring students, declaring it to be the 'devil's scale'. At first I burst out laughing, but levity quickly gave way to a disconcerting gloom when I thought of the naive and impressionable minds that may fall foul of this ignorant superstition. I would urge you be vigilant lest your trusty 6-string be condemned, seized and burned.

PS: Imagine what the ancient Locrian bards and minstrels would have thought about their dubious satanic association in 2008. Perhaps even back then there was a Lyre tuning condemned as the work of Loki, Lord of the Underworld.



Guy Pople is a music, education and multimedia specialist based in the UK`s North-West. He plays guitars, studies theory and runs St Annes Music in Lytham St. Annes, a one-stop shop for musicians on the Fylde coast of Lancashire. St Annes Music offers professional instruments, recording, tuition and accessories.

His live band Nomad is currently building up their original music. You can catch him
on Virtual Strangers.

Guy Pople

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