A built example by our firm in Washington, D.C. is strikingly similar to several proposals given here. It does, however, exceed by one the given limit of 20 voices.
GREAT
Open Diapason 8 (1-25 in facade)
Hohl Flute 8 (1-12 stopped wood, 13-58 open metal)
Octave 4
Harmonic Flute 4
Twelfth 2-2/3
Fifteenth 2
Seventeenth 1-3/5
Mixture IV 1-1/3
Swell to Great
SWELL (expressive)
Geigen Principal 8 (1–9 = Sal. + L. Ged.)
Salicional 8
Celeste 8 AA
Lieblich Gedackt 8
Gemshorn 4
Flageolet 2
Mixture III 2'
Bassoon 16 (1-17 L/2)
Trumpet 8
Oboe 8
Tremolo
PEDAL
Bourdon 16
Open Diapason 8 (1-4 from Great, 5-14 in facade)
Bass Flute 8 (ext. Bourdon)
Octave 4 (ext. Open Diapason)
Trombone 16 (full length)
Trumpet 8 (ext.Trombone)
Great to Pedal
Swell to Pedal
Mechanical key action, electric stop action
Further details may be found at http://www.dobsonorgan.com/html/instrument..._rockcreek.html
John Panning
Dobson Pipe Organ Builders