Short Octave - The Broken Octave

The Broken Octave

A variant of the short octave added more notes by using split keys: the front part and the back part of the (visible) key controlled separate levers and hence separate notes. Assume the following keys:

E F F# G G# A

with both F# and G# split front to back. Here, E played C, the front half of the F# key played D, and the (less accessible) rear half played F#. The front half of the G# key played E, and the rear half played F#. As with the short octave, the key labeled E played the lowest note C. Thus, playing the nominal sequence

E F# (front) G# (front) F F# (back) G G# (back) A

the player would hear:

C D E F F# G G# A

The actual note assignments can be seen in the following diagram.

It can be seen that only two notes of the chromatic scale, C# and D#, are missing. An analogous arrangement existed for keyboards with G instead of C at the bottom.

According to Trevor Pinnock, the short octave is characteristic of instruments of the 16th century. He adds, "in the second half of the 17th century, when more accidentals were required in the bass, 'broken octave' was often used."