I am a self taught musician (guitar/keyboards) with a limited knowledge of written music theory. For example if you asked me to play an augmented fourth I wouldn't know what you meant but if I observe you play it I would understand exactly what you were talking about.

Regarding the infamous "Devil's Tritone" that was banned by the church in the middle ages. To my mind tritone implies three notes, yet I only know of two which are used extensively in Heavy Metal for the evil, doomlike quality it lends a composition (Enter Sandman by Metallica is an example: E/A#). Dependent on which key you are playing in - E/A# F/B F#/C G/C# and so on.

My question is all references and instances of this only seem to use two notes. What is the third note that composes the Devil's Tritone?

1 Answer 1


The weird thing about a tritone is that it isn't comprised of three notes, it's technically just an an interval of

three whole tones

...hence the tri tone

in other words, 6 semitones, an augmented [sharp ♯] 4th or diminished [flat ♭] 5th, between only two notes...
... which makes your above 2-note comparisons absolutely correct - each of those is a tritone.

Where the 'devil' may be found, I'm not really sure.

There's nowhere else you can go with a tritone... add another 6 semitones to try make it more 'devilish' & you end up back at the octave.

The most famous example [imho] has got to be the intro to Purple Haze, by Jimi Hendrix.

The opening guitar riff is simply B♭ to its octave.
The bass, meantime, is letting us know we're rooted on E.
There's really nothing more to it - yet it's a game-changing noise.

Wikipedia has a mind-numbing explanation of a Tritone
There's also a fair treatise on Purple Haze itself

  • OK that makes sense, I still don't get what you mean by augmented 4th, but flattened 5th I understand, in the key of A the 5th is E so the flattened 5th is D# (Or E flat). I believe it was labeled the "Devil's Tritone" in the middle ages by the church and there was some ban on using this tritone in any compositions due to it's "Evil" sound . I'll do a bit of research into this and see if i can find some verification. Nov 13, 2016 at 21:34
  • Halfway between a 4th & a 5th - in A that would be D & E - there's D♯/E♭. The name depends on what key you're in, but it's the same note., that note is 6 semitones [three tones] up from A. Whether you consider it to be an augmented [sharp] 4th or a diminished [flat] 5th also depends on what key you are in. They're all just different ways of describing the same interval
    – Tetsujin
    Nov 13, 2016 at 21:43
  • 1
    I think I've got it, sharps or flats, I always wondered what the criteria is for whether you should label a note or a chord a sharp or a flat for example when should you use D# instead of E flat. Nov 13, 2016 at 21:59
  • I ought to tweak my answer to include aug=sharp, dim=flat. I maybe wasn't too clear.
    – Tetsujin
    Nov 13, 2016 at 22:02
  • Augmented = Sharp and Diminished = Flat, no that's cool I think I've got it, if someone asks me to play a diminished 5th I'll know exactly what they mean now. Thanks Tetsujin I've learned something today I didn't know yesterday. Nov 13, 2016 at 22:13

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