The swell box appeared in organbuilding before the birth of J.S. Bach, but was only in modest use by the time of his death in 1750. Even though the concept of expression in pipe organs is historically old, the Swell has had mixed reviews in recent years, and a rethinking of its purpose is a constant in organbuilding.
Rather than discuss the swell box itself (July 1980, p.17), I will continue the analysis of the divisions of the organ which began with the Great (Feb. 1985, p.42) and continued with the Pedal (May 1986, p.86) and which now focuses on the tonal design of the Swell.
Beginning in the 17th century as an expressive single stop such as a cornet, or a small echo division, the Swell expanded slowly through the 18th century in Spain, France and England. Some of these early Swell divisions reached to ten or more stops, but were not major divisions of the pipe organs in which they appeared. It is, perhaps, in England where the Swell first took on its character as a major tonal department and contained voices which were the equal of those in other divisions both in strength and musical validity.
The idea of the Swell began to spread throughout the organ world in the late 18th century- a time of some confusion and strange experimentation in organ design. Abbé Vogler and others were introducing such things as a device which brought on more stops as a given key was depressed (a type of crescendo controlled by key depression), variable wind pressure to secure expression, and many theatrical effects and dead-end tonal concepts. The Swell was an integral part of these gimmicks, a fact which did not help its legitimate usage in the pipe organ.
Two developments in the middle of the 19th century brought the Swell to full maturity as a division within the pipe organ.
Henry Willis in England produced the so called full swell, and Cavaillé-Coll in France developed the symphonic organ. The Willis tall swell depended really on only one specific effect achieved by having powerful reeds at 16-8-4 used with a mixture. This controllable fury became a popular sound and was widely copied. It survives today as a basic sound of a large organ with a Swell. There were other sounds in the Swell (pair of strings, diapasons, flutes) and these, too, became as much a part of the Swell concept as the reed-mixture effect. The Cavaillé-CoIl concept was in deep contrast to the Willis idea. The Willis Swell at St. Paul's London had pitches at 16-8-8-8-8-4-2-III-16-8-8-4, and the Cavaillé-Coll at Sainte-Clotilde was 8-8-8-8-4-2-8-8-8-4. Each would have far-reaching consequences in organbuilding, but we generally overrate the importance of these Swell and Récit divisions within the pipe organs in which they were installed; the majority of the ranks in Willis or Cavaillé-Coll instruments were unenclosed, and any good student of Franck will realize that the unenclosed Grand-Orgue is far more important than the Récit.
In Germany and northern Europe the Swell was rare and unusual in design until the late 18th century, and its tonal character remained curious and highly original. Free reeds, strange flutes, no developed chorus work, and exotic atmospheric effects were common. It is hard for us to know now how a division containing a Physharmonika, Terpodion, Bifra and a Harmonika might have been used, and these stops have disappeared from current organ design.
By the 20th century, the Swell had achieved great size, and many organs have been built in which the Swell has more ranks than the Great.
An interesting misconception about the Swell is that it was always the home for the celeste, and that the symphonic organ always had one. A study of American pipe organs from the 19th century reveals that even in late designs containing large Swell divisions the celeste is quite rare. The deficiency would soon be corrected with a vengeance!
The late 20th century found considerable criticism directed at the Swell and the swell box. Purified organ designs had little use for the Swell and its historic development within the pipe organ, so it was discarded. Both the swell box and the tonal designs of the Swell division could not be justified as a part of strict organ reform ideas. Although the reform movement produced a rethinking of organ design theory, the white heat of revolution burned away those things outside the decalogue of dogma. A cooling off of reform fever did eventually allow for the Swell to return, and a broader design philosophy is now available for the organbuilder with the continuing renewal of a wide range of tonal resources from the past. The Swell does not have to be a part of pipe organ design, but it has been continuously used in pipe organ building for 300 years, and its validity can no longer be challenged nor its use denied. The Swell is simply another available aspect of organ design for the builder and client to use or not to use as the situation demands. Its musical value is no longer in question, and like anything else in the organ it can be used or misused for pleasure or embarrassment. The broad range of tonal design available for the Swell has contributed to its widespread use, and its continued development and place in the organ seems secure as the instrument continues to evolve and retain its place as the King of Instruments.