Diminished and Augmented Chords

In this lecture, we will delve into the history of opera because that is where the diminished seventh-chord gradually accumulated its expressive power as a chord for dramatic climaxes, demonic intrusions and generally for shock and horror of any kind. The augmented triad came to be used for the mysterious and supernatural. The symmetrical structure of these two chords allowed composers to veer off into unexpected keys or create new scales which have not shed their strangeness, even today. &nb...