This article in our series about tonal architecture looks into the pipe organ stoplist. Some would claim that the stoplist is the most important part of the tonal design of an organ, but I view it as something less, and more confusing and distracting than we would hope for.
In architecture, a sketch is used to convey the basic architecture and style of a building. It may include some dimensions, a few details and outlines, and even a few indications of materials. But a sketch goes only so far, and only the blueprints, a complete book of specifications, and much onsite collaboration can be used to build the building. An organ stoplist is something like a sketch. It conveys the basic ideas of the tonal architecture, indicates some materials, and provides an overview of the instrument and the foundations of its tonal style.
What seems inconceivable is that the pipe organ stoplist gives us only bare hints of the sound We can imagine certain effects based on our interpretation of the stop names and choruses, but the precise and full character of the sound cannot be deduced from a stoplist or for that matter from any other document.
We are on firmer ground when it comes to comparisons. A Great division from 1910 might contain stops at 8', 8', 8', 8', and 4'. A more recent Great might be 16', 8', 8', 4', 2', Mixture, and Trumpet. It would be easy to describe the differences between the two. But given two modern stoplists with exactly the same names and pitches, we would be lost in trying to describe the differences between them. Only until the organs could be heard live would we be able to hear the differences, and they would not relate to the identical stoplists.
If we went beyond the stoplist to pipe scale information, we would only gain a bit more. The scaling is more like a blueprint than the sketch/stoplist but the scaling is such an arcane bit of pipe organ data that it would not convey much to an organ committee member or to an organist. Even at that, the scaling and stoplist together are not the entire picture, since there are more than a dozen parameters of each pipe in an organ that are directly involved with forming the sound. None of this includes what the voicer and tonal regulator will do with the hundreds or thousands of pipes.
Organbuilders are frequently surprised by the results of a finished instrument in the complex acoustics of the room. This is part of the mystery and the glory of trying to design a large and complex instrument, which is the pipe organ, for a specific location.
If not a tonal picture of the organ, then what is the stoplist? It is the start of the tonal architecture, it is a guideline to tell us what we are doing, where we are heading, and what our formal organization will be.
Many organists and enthusiasts hold the stoplist as an all-important never-changing control of the sound and design of the organ. In a small instrument, this may be the case, but in a large pipe organ, the builder is striving to obtain the maximum from the funds and space available. Changes in the stoplist are both inevitable and desirable. Hardly any large pipe organ is installed according to the "original" stoplist. The changes are a study in themselves, revealing something of the complex mental processes a builder uses to create the design.
Even for the builder, the stoplist may not instantly bring up tonal images and a clear sonic picture. The builder uses the stoplist as a way to organize thoughts, create a tonal edifice in the mind, and lead the way to the final construct.
We still do not know the answer to the question, "Which comes first, the stoplist or the sound?" For some, the sound of a proposed organ predates the creation of a stoplist. For others, the sound only emerges into conscious thought as the stoplist is written down. The idea that the sound exists before the stoplist is akin to Michelangelo bringing out the figure already pre-existing in the block of stone; a romanticized concept in which even Michelangelo mocked the idea by stating that he carved marble by removing everything that wasn't needed. In that sense the stoplist evolving from a proto-sound is merely writing down the stops that fit that sound, and leaving everything else out.
I suspect the reality of making pipe organ stoplists is a combination of both having sound in mind while picking out the stops, but also finding the surprise of arranging stops in new ways to elicit a mental sonic image.
Our tonal curiosity is activated when it comes to stoplists of organs long since gone. Trying to imagine what an ancient organ sounded like from studying the stoplist may be a futile effort, but it has rewards for the imaginative builder. It is easy to recreate that which we can never hear, and it is even easier for us to rationalize our own inabilities at replicating that which still exists.
In the 1930s, Ernest M. Skinner became nothing more than a figurehead at Æolian-Skinner, while G. Donald Harrison was fully in charge. Skinner raged at both the company and Harrison for abandoning the "Skinner" organ. Both Skinner and Harrison supervised Æolian-Skinner organ installations at this time, but even modern experts are hard pressed to find the extreme tonal differences between the two that generated such heat from Ernest Skinner; even the stoplists look alike. If we, today, find so little difference compared to the wholesale and obvious differences they saw in their time, then it must be obvious that tonal architecture is a subtlety that can easily elude us, confuse us, and lead us to false conclusions.
The stoplist may not be the total picture and predictor of organ sound we wish it could be, but it does help us to explain ourselves and to convey certain concepts to those who wish to try to understand what the organ is, or will be, all about. The stoplist is a useful and convenient crutch to help us on the treacherous path of the tonal understanding of an organ, and it will survive as the simplest way to categorize and contract for the King of Instruments.