|The Principal 8' is a voice that has survived more than 400 years because of the beauty and musical utility of its sound. It is a voice of fundamental importance, so universal that it is often overlooked and taken for granted.
The wonder of this stop is its acceptance across broad national boundaries and centuries of time. I have no explanation for its universality, but a look into its history and development is worthwhile.
In late medieval times, the organ was taking shape as a multi-keyboard instrument of increasing complexity and sophistication. By the Renaissance, the organ contained most of the voices which would characterize it for centuries to come. The Principal 8' became an integral part of these rapid and far reaching developments.
One of the mysteries of musical instrument history is the establishment of pitch. Somehow, a rank of pipes with an 8' open pipe for low C became widely recognized as "normal" pitch. The sound of a rank of 8' open principal pipes seems to have an intrinsic or universal appeal and it became a frequently used rank among organbuilders of every background and era.
There is no record of when the first 8' Principal appeared, what it was made of, how it sounded, or how it was voiced. But in the centuries since its first appearance, it has been made from a bewildering array of materials. Even in ancient times it was made in mixtures (not alloys) of tin and lead ranging from 100% tin to nearly 99% lead (100% lead is not used since it is so soft that the pipes collapse). It can also be successfully made of copper, zinc, aluminum, many kinds of wood, paper, and plastic. Some were made from empty beer cans during World War II. Most people do not realize that the air inside the pipe and not the pipe material creates most of the sound. The pipe material has a slight but important effect on the tone.
The names associated with principals are even more bewildering than the materials used. Diapason is an old, evocative, and somewhat mysterious Greek word for the rank. Principal, Prinzipal, Prestant, and other variants have been popular and even trendy. Montre is French and somewhat carelessly used outside of France. The names, unfortunately, mean nothing and builders have used them with abandon. One person's Diapason is another's Prinzipal, and vice versa.
Though we register by name, we should rely on our ears rather than our eyes to make effective registrations. For years I could not understand how blind organists registered so effectively, but eventually realized that they were not being misled by what was engraved on the drawknobs. They knew far more about sound than those who could "see" what was being registered.
The universal admiration for the 8' Diapason eventually bordered on myopia as the early 20th century found its use being expanded at the expense of the other principals at 4' and 2' and the mixtures. These upper voices disappeared and many organs had one huge engulfing Diapason 8' which covered most other ranks. The number of 8' Diapasons also increased as it became common for large organs to have two, three, or more 8' Diapasons on the Great manual. This culminated in the all-time champion usage of them in the 1930 Atlantic City organ with ten straight and two more borrowed 8+ Open Diapasons on the Great alone, and more than 24 of them in the entire organ. The reason for multiple 8' Diapasons on the Great was that each was different in power and tone. Number one was the loudest (an appropriate word), and higher numbers indicated progressively less intense sound. Thus, the organist could theoretically create any dynamic level of 8' Diapason tone in an ensemble.
As a reaction against such numbers, in the 1930s, the inventive tonal designer Ernest White rejected the 8' Diapason and designed many organs which had none. The idea spread and many organs had a principal chorus but no 8' Principal-an 8' Stopped Flute taking its place. From excess to rejection is a normal process in art history, and the 8' Diapason had in a few years gone from over whelming abundance to near extinction. Such extremes were the work of only a few, but they had far-reaching effects. The neo-Baroque (not true Baroque) trend brought back the complete principal chorus with a small-scaled lightly winded 8' Prinzipal. More recently, the Principal 8' has been strengthened and is now included with rich, substantial voicing in most instruments, and with a complete chorus above it.
The use of the Principal 8' still poses problems for some, and lingering suspicions and doubts in others. This fear is probably based on the difficulties encountered in the voicing extremes of various examples in the recent past. At a recital some years back by a famous touring European organist. the solo in a Bach chorale prelude utilized the Principal 8' alone. A noticeable dither in the audience was a sure sign that the credentials of the performer were being weighed.
In the best traditions. the Principal 8' might be the most frequently used and most important voice in the pipe organ. Its use cannot he avoided, and indeed should be encouraged. It is at the heart of the organ's tonal architecture, as the entire edifice of the' organ's sound is built upon it. Many organs have been built without an 8' Principal, but any organ of consequence and size should develop musical values with it as an important and well-voiced center of sound.
A curious development was the combination of an 8' Stopped Flute and an 8' String used together as a substitute for the 8' Diapason. Some organs had these ranks scaled and voiced not to create good and separate flute and string sound but to resemble the diapason sound when used together. This odd sub-chapter in diapason history has now nearly disappeared, but represented widespread thinking some years ago. It was never totally successful, though some examples were interesting.
One of the great artistic problems for the organbuilder is getting the Principal 8' just right. Too big, and it swamps other voices and muddies the chorus. Too weak, and the organ sounds thin. Too dull, and the sound is fluty. Too stringy, and it does not blend. No two builders voice alike, but one of the acid tests is whether the Principal 8' has that full singing quality that cannot be described.
The 8' Diapason, Principal, or Montre has been with us continuously for hundreds of years, an important and useful sound in the pipe organ. No organist should be unaware of its history or importance, and no organist should avoid it out of ignorance or fear. Its bizarre recent history, and the confusion about its role in the organ, should now be behind us. It has regained its proper place in the organ, and its vital sound is at the very heart of the king of instruments.