Zombies and Zombettes, gather ye round. It’s that ghoulish time of year when a guitarist’s thoughts turn to such devilish delights as the tritone, the minor third and – gasp! – even the dreaded flat second! The horror! These demonic musical intervals can create an unsettling feeling in the listener, scare off household pets, open a gate to the land of the undead, and maybe even make a few shirtless dudes crowdsurf.

Let’s look at each of these morbid musical mindfreaks individually before combining them into one super-doomy scale…

Diabolus In Musica
Take a regular power chord shape. Sounds nice, huh? Tonally neutral, powerful, straightforward. Now move the higher of the two notes back by one fret. You’ve just unleashed hell, my friend. Known as Diabolus In Musica or more boringly the Tritone, this is the terrifying interval was designated as dangerous in the 18th century. Legend has it that just by playing it you could summon Satan himself and therefore get excommunicated. And probably mauled by Satan, I guess. You can hear this interval put to suitably devilish use in “Black Sabbath” and “Symptom Of The Universe” by Black Sabbath – it’s that ‘set your teeth on edge’ interval that clashes so very perfectly against the rest of the song.

The Minor Third
The Minor Third (three frets higher than the root note) has a powerful and slightly unsettling effect which sets itself up for a nice sonorous resolution when it goes back to the root note of the scale. You can hear this being walloped on “Fuel” by Metallica or the first chord of the main (only?) riff of Ministry’s “Just One Fix” (a riff which makes its way up to the Tritone for extra aggression). It can sound pretty mean in the right context, and it works great in pentatonic blues licks as well as mega evil metal.

The Minor Second
More simply defined as “one fret higher than the bottom note,” the Minor Second has that ‘Jaws is lurking nearby’ feel, and it tends to add an urgent, fevered feel to a riff. You can mine an awful lot of sonic sludge by exploring the relationship between a root note and the fret directly to the east.
So I’ve thrown these three intervals into the cauldron, along with a few gnats, a few newts and a couple of other notes to come up with my own deliciously eeeevil scale. I call it… The Dragon Scale.

As you can see, the first four notes of this scale are chromatically sequential – in other words, each of those notes is one fret away from the next one. Then there’s a big leap from the G on the sixth string to the A# on the fifth, and another big leap from the B on the fifth string to the open D on the fourth. It may sound strangely atonal when played out of context, so let’s listen to it used to form the basis of a song. Just as each of the three intervals explained above has a specific spooky effect when played off against the root note, you’ll find all sorts of devilishly fun intervals buried within this scale.
Wanna hear it in action?

The Dragon Scale by Peter Hodgson
The arpeggio in the second bar is an example of the kind of intervallic unease this scale can conjour.

And here’s the Sabbath-esque riff.

I recorded this using a Buddy Blaze Sevenator seven-string prototype with a poplar body, maple neck and ebony fretboard, and Seymour Duncan Full Shred and ’59 humbuckers. The amp is a Marshall DSL-50, and the speaker cabinet is an AxeTrak isolated cab. And that’s it, aside from a few ambient effects here and there added during the mix.
What’s your favourite evil interval? Which notes do you use to summon the undead, rattle some bones and haunt a foggy cemetery or two?