Steven Hoover explains different types of pipes and how they are voiced.
Berghaus Pipe Organ Builders Inc. has grown to become a leader in the design and construction of pipe organs. The company continues to explore the art, form and role of the pipe organ in today's environment. To make the presentations more manageable, people were subdivided into groups, which rotated between different topics:
Design
Berghaus designer, Michal Leutsch, showed how he uses AutoCAD to design everything from the decorative casework to the steel support structure to the chestwork layout (where the pipes are located.) There are many aspects of designing the casework of the organ. Each rank (set of pipes of the same sound) must be able to project its sound out into the space, must be reachable by technicians for the purpose of tuning and maintenance, and obviously must be able to physically fit.
Tonal Director Jonathan Oblander described how the "sound design" of each instrument is conceived. He explained how they really work with the client's space to determine what will work best for their needs. This means looking at architectural drawings, visiting the space and even playing the existing organ (if there is one). Many clients already have an organ, which they want to refurbish or expand.
Construction
Construction of the structural as well as aesthetic features of the organ casework all takes place in house. They also build the bellows, windchests, ducts, and console (where the organist sits). Materials and finishes are selected to blend with the client's existing architecture and décor. Commonly used woods are oak, poplar, and walnut. Kelly Monette explained that the organ is completely built in their shop, taken apart, shipped to the client's site, and put back together again.
Voicing
Steven Hoover and his colleagues work with every individual pipe to make small adjustments in the timbre, pitch, and loudness (collectively called "voicing"). A typical instrument can contain thousands of pipes, so this is quite an involved process.
There are two basic types of pipes: flue pipes and reed pipes. Flue pipes are what most people think of as a "pipe." Air flows up through the foot of the pipe and is forced through a small gap at the mouth. Some of the air is diverted outward, while the rest sets up a standing wave in the main body of the pipe, creating the tone.
A reed pipe, by comparison, has a similar mechanism of sound production as a clarinet or saxophone. The actual reed or "tongue" is a thin strip of metal that vibrates as air is blown through the pipe. A resonator tube functions much like the body of an oboe or trumpet.
