Thu Aug 31, 2017 5:53 pm
Dinko -
The Bonn-Beuel Oberlinger organ is relatively "French" despite its physical location in Germany. (OK, some would argue that the voicing is not adequately or successfully French, but I like it, anyway.) Following the French design paradigm, each division of the Bonn-Beuel organ includes windchest(s) for flue stops that are automatically "on," or in other words receiving wind from the blowers/bellows. (In some French organs, the G.O. flue windchest may not be automatically "on.") In addition to their windchests for flue stops, each Bonn-Beuel division has a separate windchest that receives air only if its own connection to wind supply is opened by activating a "stop" at the console. In the Bonn-Beuel Oberlinger organ, these "stops" or wind controls are numbered 7, 8, 9, and 10. Each includes the words "Appel Anches" (= "add reeds") and then the short reference to each division: PED, G.O., POS, and REC.
It may be unusual that in the Bonn-Beuel sample set (and presumably in the original pipe organ), ALL of the speaking stops on the right-hand side of the console belong to Anches (reed) windchests. The sample set is modeled correctly in that you must "draw" the appropriate "Appel Anches" wind control (#7, 8, 9, or 10) in order to have ANY of the stops in the right-hand panel for that division to produce sound. This kind of design is a historic way to prepare registration for sudden addition (or cessation) of large/brilliant sounds. Note that not all of the "Anches" stops are actually reeds: instead, some are flues that add bright color and are frequently called upon in connection with reeds.
I hope this understanding solves your riddle.
Enjoy!
Don Vlazny