IFDO

An IDO (inverse-arithmetic division of the octave) or ELDO (equal length division of the octave) is a periodic tuning system which divides the octave inverse-arithmetically rather than logarithmically, which means it is divided proportional to the length of a string to be divided. All IDOs are subsets of just intonation.

Formula

Within each period of n-ido, the frequency ratio c of the k-th step is

[math]\displaystyle{ \displaystyle c = (2n)/(2n - k) }[/math]

Individual pages for IDOs

• 2ido
• 3ido

See also

• EDL – equal division of length, a similar concept
• ADO – arithmetic division of the octave
• EDO – equal division of the octave