Excalibur Diabolus in Machina.

Everyone knows that the devil is in the details. And because creative irreverence is a temptation that Roger Dubuis finds irresistible, Excalibur Diabolus in Machina pushes sophistication to breaking point.
Roger Dubuis has chosen to tune its minute repeater to the sound of the tritone, the famous “Diabolus in Musica” chord outlawed in medieval religious music, the secret key to all clever and complex melodic harmony.