Wild Air

So, if you’ve been following along, we’ve come up with the perfect recipe for the delicious soup that will be the Shelbyville organ.

Let’s see… In a 4 quart pot, combine 3 quarts of hearty broth, 2 quarts of tomato sauce, 2 1/2 pounds of beef, 4 large potatoes, 2 large onions, 3 celery stalks, and 3 cups of water.

Do you see the problem? If not, reread the recipe carefully.

We’ll wait… … … …

No matter how great the recipe, ultimately¬†it all has to fit into the pot! And, if the pot is too full, you won’t be able to stir the soup (tune the organ) without making a mess. Sadly, we encounter too many organs that are nearly unserviceable because too much was installed in a space that was too small.

Designing an organ that will fit into its allotted space requires a great deal of thought and engineering. In the large organ companies of the past, the first job an up-and-comer would be given was usually in the drafting room. Today, at Reynolds Associates, we use sophisticated computer-assisted drawing to fit our designs into the space available. Later, as we will see in a future posting, those drawings are translated into actual components with our CNC router system.

The first step in the process is to prepare a simple floor-plan of the space where the wind chests and pipes will be placed. Then, we discuss how we want to arrange the divisions of the organ relative to each other. At St. Joseph’s, we decided to place the Swell division behind the Great. This is similar to Moller’s arrangement, although each division will be nearly twice as wide.

Since the Swell will have expression shutters, it has to be behind the Great, so it does not block the sound projection (the fancy term is “tonal egress”) of the unenclosed Great pipes. This also makes sense because the hard wood of the shades helps to reflect the sound of the Great. If, instead, we placed the Swell and Great divisions side-by-side, the swell box would create an acoutical “shadow,” blocking some of the sound of the Great pipes.

Here is the layout for one of the four main windchests for the Shelbyville organ. Each circle represents an individual organ pipe.

The next step is to decide where each stop will be placed within each division. David Reynolds usually does much of the layout work. Based on his experience as a tuner, he knows, for instance, that you have to be able to reach each pipe from the service walkway. Mixtures and reed stops, for instance, are usually close to the tuning walk, while taller pipes are farther away. Celestes and the stops they work with need acoustical separation to work properly. In the particular case of Shelbyville, we are using two different wind pressures on the Great division, so the stops must be arranged based on the pressure upon which they will speak.

Finally, David plans the location of each individual pipe in the organ, taking care that no pipe interferes with the speech of any other pipe. Larger pipes from several stops may be placed together at the back of the swell box, where they won’t get in the way of tuning the smaller pipes.

In some cases, space may require us to revise the stoplist. At St. Joseph’s, for instance, there was not room in the Great for an independent 4′ flute. So, we “borrow” the 4′ flute from the 8′ flute. This means that the pipes of the 8′ Gross Flute also serve for the 4′ flute as well. This small compromise makes it possible for the organ to have some other useful voice in the Great, such as the 8′ Unda Maris, the pipes for which are similar in size to a 4′ flute.

Most of this process takes place before we present a final plan to the committee for approval. While the internal arrangement may undergo some additional revisions, planning it all out on the computer helps us to be sure it will all fit before the decisions are made.

Next time:

Making the new organ affordable…

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