Adlung writes: A Koppeloktave 4' stands at present in the palace at Dresden in addition to an Oktave. Perhaps this means a Gemshorn 4'... Koppeloktave is also found in the stoplist [of the palace organ at Dresden] that Praetorius gives. Audsley, in his entry for Koppel, writes: �This valuable stop in the old Organs was sometimes labeled ... Koppeloctave or Koppeloktav when of 4 ft. pitch. ... The 4 ft. stop [is found] under the name Copula Minor.�
No examples of Coppeloktave, Koppel Octave or Koppeloktav[e] are known. Contributions welcome..