Key transposition and chord finding accessory - has base grid showing chromatic scales and slide cursors with windows to show chords etc.

摘要

The accessory is intended for finding keys, tone-scales and chords in different keys to facilitate transposition. It comprises a base plate with a grid showing the twelve notes of the chromatic scale, e.g. F, F flat, G etc and F, Fsharp, G etc, along each horizontal line, the scales in alternate lines being displaced by the same amount. A cursor is horizontally slidable above the plate and is provided with windows which are arranged such that, in each position of the cursor, they show a key, or tone-scale and/or chords in that key on the grid below it. Different cursors are provided for different tone-scales.