Diabolism and the police

garrick92 · 63300. Sat Apr 01, 2006 3:00 pm

Q: What's so evil about this noise?

[GRAMS: 1970s blues and twos siren]

A: The interval between the 'nee' and the 'naw' in 'nee-naw' (that's a technical term) is an augmented fourth, two notes separated by three whole tones.

This tritone was condemned by religious authorities throughout most of the last millennium as the 'diabolus in musica' (literally: 'the devil in music'), and was actively prohibited. The various supposed ill-effects of listening to the devil's interval included licentiousness and communion with The Evil One himself.

Anyway, the reason it was used for the emergency service sirens is because it is so jarring you can't help noticing it (being played at 5gazillion decibels probably helps). And if someone's dashing around on blues and twos, chances are that something evil HAS actually befallen someone. It just goes to show.

S: Just about any musicological work, including the Oxford Companion to Music (which is what I used).

MatC · 63517. Mon Apr 03, 2006 6:01 am

Oh, lovely! Links to Flash at post 63492

Frederick The Monk · 64279. Fri Apr 07, 2006 11:41 am

and links to decibels of course.

Gray · 64286. Fri Apr 07, 2006 1:11 pm

You'll need some speakers and a modern computer to hear these (it's in MIDI format), but here's a minor third, and here's an augmented fourth (also known as a diminished fifth).

Sirens actually make both noises. European sirens are an augmented fourth (the second one), but British sirens (the ones that go nee-nah, like a spiteful child) are a minor third.

Kodaly composed quite a lot of music around the minor third because he realised that children automatically use this interval the world over, irrespective of culture or race. Pinker picks up on this too in The Language Instinct.