Learning aid for musical theory, comprises three discs divided into spirally and circular arrangement of sectors for teaching about intervals, harmony and church modes

摘要

A chromatic scale or another tone system comprising an array of equidistant tones rising in notes over more than octave pitch is arranged concentrically in the form of a spiral on a medium disc and is divided in the radial direction into a number of sectors (11-19) corresponding to the number of monoharmonically exchangeable tones per octave. A smaller rotatable disc placed concentrically inside the medium disc is also divided into the same number of sectors arranged as a spiral with the musical interval terms relative to a given field in a sector. The smaller disc has a circle with terms or markings for identifying the chord in the root position and its inversions relative to a given field in a sector. Both discs are mounted on a large disc divided into the same number of sectors arranged in a circle, which contain labels or markings for identifying the scale.