User manual

Table Of Contents
RELATED LINKS
Custom tonality systems on page 615
Equal Division of the Octave (EDO)
EDO stands for Equal Division of the Octave: the number of equal pieces, or intervals, into which
an octave is divided.
Traditional Western harmony is based on equal temperament, another method used to describe
tonality systems, or 12-EDO, as the traditional scale from C-C is made up of twelve steps spread
across the seven notes in the scale.
For example, between the notes A and B there are two steps, but between B and C there is one
step. This is because in 12-EDO, each step represents a semitone, and there are two semitones
between A and B according to standard equal temperament, but only one semitone between B
and C.
Other tonality systems can have different equal divisions of the octave, for example, in 24-EDO
each octave division is a quarter tone. However, the only tonality system in
Dorico SE is 12-EDO.
RELATED LINKS
Custom tonality systems on page 615
Custom tonality systems
Custom tonality systems allow you to specify a unique number of divisions of the octave for your
project. This can be useful for music not based on traditional Western harmony. Custom tonality
systems are only available in Dorico SE if you open a project that already contains them, and you
cannot change where they apply.
Key signatures
Tonality systems
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Dorico SE 3.1.10