page_title: Short octave
section_title: Broken octave
hierarchical_section_title: Short octave / Broken octave
caption_attribution_description: Français&#160;: clavier de clavecin (Rouaud) avec feintes brisées
context_page_description: The short octave was a method of assigning notes to keys in early keyboard instruments, for the purpose of giving the instrument an extended range in the bass range. The rationale behind this system was that the low notes F♯ and G♯ are seldom needed in early music. Deep bass notes typically form the root of the chord, and F♯ and G♯ chords were seldom used at this time. In contrast, low C and D, both roots of very common chords, are sorely missed if a harpsichord with lowest key E is tuned to match the keyboard layout. A closely related system, the broken octave, added more notes by using split keys: the front part and the back part of the key controlled separate levers and hence separate notes.
context_section_description: 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 G♯. 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."
caption: This harpsichord built by Clavecins Rouaud of Paris employs the broken octave scheme.
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