A term coined probably by the Orgelbewegung of the 1920s to describe the system for building organs in which each ‘department’ or Werk (i.e. a keyboard with its chest or chests and pipes) has its own separate structure. For convenience the keyboards (manual or pedal) are brought together at one console, but the earliest examples of the Chair organ (Utrecht, c1390) may also have had their keyboard separate, behind the organist. Structurally separate but acoustically an entity, an organ could be built up of several discrete divisions depending on requirements. A likely order of size is:
Usually, each department is built up on a Diapason rank (16' pedal, 8' Hw, etc.), hence the wrong explanation of the term as denoting ‘Werke based on a Prinzipal’. Almost all organs before c1700 were built according to one or other of the plans; exceptions were those French, south-east European, Spanish and English organs in which subsidiary chests were placed within the main case (cadireta interior, Echo, solo Cornet, etc.). The system's reputed advantages are that separate cases ensure maximum resonance and dispersal, departments can be added (at Lüdingworth, Hw/Bw of 1598, Rp/towers 1682) and such departments have different function and sound; but non-Werkprinziporgans also allow for this, and the strongest reason for building Werkprinzip organs today is that the organ music of 1500–1720 was written for this type.
Hw
Hw
+
dep. pedal
Hw
+
Bw
+
dep. pedal
Hw
+
Rp
+
dep. pedal
Hw
+
Rp
+
independent pedal
Hw
+
Bw
+
pedal towers
Hw
+
Rp
+
pedal towers
Hw
+
Bw
+
Rp
+
dep. pedal
Hw
+
Bw
+
Rp
+
pedal towers
Hw
+
Ow
+
Bw
+
Rp
+
pedal towers
(Hw = Hauptwerk; dep. pedal = pedal pulldowns; Bw = Brustwerk; Rp = Rückpositiv; Ow = Oberwerk; pedal towers = 1 or 2 chests in tall boxes to right and left.)