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Voicing a pipe organ is the ultimate convergence of science and art

pipe organ
Photo: Paul T. Roberts

In a 12-by-12 wood-paneled room, squeezed between hundreds of church organ pipes, Robin Côté lifts a large tin pipe out of the hole in which its resting. He squats onto the narrow walkway where he stands, grabs a “spatula,” and makes an imperceptible adjustment to the edge of a rectangular hole. He replaces the pipe, says, “OK” to someone outside the room, and air rushes into the pipe. Robin listens. He seems pleased and calls for the next pipe to be played.

Robin is president of Juget-Sinclair Organbuildersin Montreal, Canada, and has been an organbuilder since 2002. He is inside an elevated chamber of a 24-foot-high choir organ his company scratch-built and installed at the Cathedral of the Sacred Heart, in Richmond, Virginia. Robin, along with organbuilder Alex Ross, are voicing the organ.

“The voicing process is the final step to complete the project.” Robin explains. “That means we are adjusting the tone, the strength of each pipe to the acoustics of the cathedral.”

Meanwhile, Alex sits at the keyboard console and communicates with Robin via walkie-talkie. He adds, “We need to go through [each pipe] one by one, make sure that it's loud enough or soft enough, bright enough or warm enough.”

For this instrument, that means Robin and Alex will voice 25 stops (groups of pipes simulating other instruments), about 1,400 pipes total. It’s a long, detailed process that takes five to six weeks. Voicing focuses on a few main elements: timbre (or tone), pitch, volume, and attack, which is how a pipe initially reacts when a key is pressed on the console. This is also known as how the pipe “speaks.”

“Timbre is what we call the color of the sound.” Robin says, “We see in the sound the different colors, so a flute doesn't sound like a violin. When you look at the pipes, there [are] different shapes.” Some of these pipes are metal and cylindrical, some are square and wooden. “Some shapes produce string tones, other shapes produce a flute-like tone. And there are other shapes that produce brass.” Perhaps ironically, the brass stops are the pipes made of wood and their sound is generated when air passes by a woodwind-style brass reed.

“What gives the timbre, the tone color of the pipe?” Alex asks, “That's often dictated by how high the mouth of the pipe is [along the pipe’s length], how fast the pipe speaks or how slow the pipe speaks, and also how loud the pipe is. So we need to control all of those parameters to make sure that each of the pipes sounds like its neighbor sounds.”

Robin holds a large pipe in his hand and demonstrates, “When you look at the pipe, you have a wind way, you have two lips, you have a languid [an internal horizontal plate that redirects wind toward the mouth of the pipe creating the windway, similar to a whistle] and you have the length of the pipe [that helps determine] the tuning. All those parameters, they have an impact on the tone and they are linked together.” Robin points out that the final parameter is maintaining a balance, or harmony, between all the parameters.

“Everything is technology in organ building, there's a lot of physics.” Robin says, and Alex continues, “There's acoustics, lots of air column theory [the study of how air moves inside pipes], but also with…the mechanical linkages between the keys of the keyboard and the valves under the pipes. You've got kinematics [the motion of objects without reference to the forces which cause the motion], you've got static for the structure of the organ so that it doesn't fall down. You've got some fluid dynamics with the air flow through the wind system of the organ.”

From the console, Alex plays a note on the keyboard. He is not satisfied with the attack of the pipe. Up in the organ chamber, Robin pulls the pipe out of its place in the ranks. He fetches a petit hammer and what looks like a punch tool. He gingerly places the tip of the punch onto the mouth’s lip, and taps it ever so slightly with the hammer. Robin replaces the pipe and asks Alex to play the note. Both are pleased, and they move on. In light of all the technology it took to construct this organ, including CAD design software, Robin took no measurements when making the adjustment. He instead relied on his experience and artistic judgment to know when the pipe sounded right. “It's all in the hand skills.” He says, “You cannot write a book about that. If I explain it to you, [and] you try to do it. It won't be the same.”

As the sound of the organ reverberates among the stone walls and ornate arched ceiling of the cathedral’s sanctuary, Alex notes, “We also try and get an idea of what are the acoustics in the church … Do we need to have an organ that's really strong to fill the space with sound? Does the sound naturally get amplified by the acoustics? Does the room favor bass [frequencies] or does it just kill the basses? So, we need to control all of those parameters to make sure that each of the pipes sound the way we want it to sound, and sound right in this church. It's really a question of taste.” He then considers the congregation, “Are people going to like the way the organ sounds? What kinds of emotions do you want this organ to be able to convey? How are you going to find a way to convey anger or love or tranquility?

Alex then sums it up, “I think, for me, the organ is the ultimate meeting point between science and art, as far as music is concerned.”

The Cathedral of the Sacred Heart unveiled its new choir organ March 28th, 2022. Robin and Alex were there for the reveal, but soon after, they returned to Montreal to continue work on the company’s biggest project to date, which is also for the Cathedral of the Sacred Heart. In two years, they will return to Richmond to replace the Cathedral’s main organ with a 15 ton instrument comprised of 67 stops and about 4,000 pipes. Robin and Alex will individually voice each one.