Why does the Tritone Sound Devilish?

Generally, the sound of the tritone has an unpleasant effect on the listener. Thus, it has been described as hideous, ugly, insidious, and diabolical. Until now, there has been no generally accepted explanation for this effect. In this paper, a reason, based on the theory of musical equilibration, is presented. The music-theoretical peculiarity of this sound is that its two leading tones cannot be clearly identified. One does not know which of its two leading tones points upward and which points downward. In an experiment it can be shown that the tritone loses all its negative sound characteristics if one briefly strikes another interval in addition to the tritone, which gives the leading tones a clear orientation. If you then listen to the tritone again, it suddenly sounds harmless. In this way, the ambivalence of its leading tones proves to be the cause of the tritone's unpleasant effect.