About Opus 19
The firm's nineteenth instrument is their largest to date and their first four-manual organ. There are three 32-foot stops, one of the first 19th-century clarinet free reeds in the USA in modern times and a set of horizontal trumpets in a tribute to the great organs of Spain.
The instrument is placed in the rear gallery on either side of the 40-foot-high Resurrection Window. This massive window necessitated a divided layout for the organ's five divisions of pipes, and several unique design solutions were used to compensate for the lack of a traditional central organ case.
The visual design of the instrument combines architectural features found in this building with elements from historic European organs. The organ is entirely encased in white oak woodwork with decorative carvings above the façade pipes. Both the carvings and the façade pipe mouths are gilded with 23-carat gold leaf. The wooden case serves a vital tonal function by blending and focusing the sound of the 5,499 organ pipes, while also protecting them from dust.
The console's four manual keyboards are covered with cow bone and ebony, and the pedal keyboard is made of maple and rosewood. The 111 stop knobs, controlling the organ's five divisions of pipes, are on either side of the keyboards. The stop knobs and toe pistons are made of Pau Ferro. Other species of wood found in the organ include tulip poplar, redwood, sugar pine, basswood, walnut, hornbeam, and Douglas fir.
The organ is laid out vertically in order to take advantage of the given space. The pipes of the Great division are placed on wind chests above the impost on the east side of the window. The Swell division is placed above the Great, hidden behind the façade pipes and gilded carvings. The Positive division is located above the Swell, almost hugging the building's 72-foot-high ceiling. The Grand Choir and Pedal divisions are located on the west side of the window, with the Spanish Trumpets speaking from the very top above the Pedal division. They are placed horizontally, just behind the façade, in order to sound in the most assertive manner possible.
Two electric blowers supply wind to the organ via six bellows measuring approximately 4 feet by 8 feet. The bellows and blowers are located behind and inside the organ's two cases. This wind system imparts a gentle flexibility to the organ's sound, allowing the pipes to sound more like a choir of human voices rather than an inexpressive machine.
The organ's tonal scheme draws most of its inspiration from the great North German and French organs of the 17th and 18th centuries. Its resources are further leavened with many stops inspired by 19th and 20th century models. This enhances its flexibility in playing choral accompaniments and interpreting the monumental solo organ literature of the 19th and 20th centuries.
The organ is tuned in "Mark Brombaugh Mild," an unequal temperament that favors the keys nearest to C major while still remaining harmonious in the most distant keys.
With the exception of the Clarinette 8' stop, all of the metal pipes were made in the Pasi shop—from the casting and rolling of the metal through to the completed pipes. They are made of various alloys of tin and lead, with trace impurities of copper, bismuth, and antimony to help stiffen the metal. To enhance the intensity of the lead pipes' sound, the metal is hammered following casting in order to tighten its molecular structure. The three 32' stops, as well as the large pipes of several other stops, are made of tulip poplar wood.
The three traditional manual divisions—Great, Positive, and Swell—are placed above the console on the east side of the window, and have normal suspended mechanical key action and mechanical couplers. The Grand Choir and Pedal divisions on the west side of the window are modeled after the Resonance division in the famous 1775 Jean-Esprit Isnard organ at St. Maximin, Provence. Most of the Grand Choir pipes are shared between the two divisions, but have independent stop knobs and actions for each division.
This divided layout of the organ, combined with the comprehensive tonal scheme necessitated by the cathedral's vast interior space, posed a special challenge in the design of the key action. Running a horizontal mechanical key action from the console to the west case 22 feet away would have been impractical. Our solution was to use the electric proportional key action developed by NovelOrg of Longueuil (Montreal), Québec.
The NovelOrg proportional key action is an all-electric action with sophisticated electronic control that allows the valves in the wind chests to follow exactly the motion of the key. Applying this action to the remote Grand Choir and Pedal divisions makes it possible to retain the sensitive control of pipe speech found in a traditional mechanical key action. In addition to the regular mechanical couplers the Great, Positive and Swell keyboards are coupled to the Grand Choir through the NovelOrg proportional action.
The stop action is electric, and the solid-state combination action allows up to 20 organists to each have 55 levels of memory, providing for the storage and recall of thousands of stop combinations. This state-of-the-art computer-based technology gives organists maximum flexibility in controlling the instrument's many tonal colors.