Imagine what the keyboard of a piano looks like. Whether an upright or grand, a piano has one set of keys. Now imagine what an organ looks like. Most people visualize multiple rows of keys (called manuals) which are played by the hands, and one big set of keys on the floor (called pedals) which are played by the feet. While pianos vary in quality, size of the soundboard and some other details, they are essentially the same instrument. When someone plays on a unfamiliar piano, it may take a few minutes to get used to the ‘feel’ of the instrument, but that is the primary distinction.
Enter the world of the pipe organ, where no two are exactly alike. True, they have things in common, but oh my, be ready for surprises. Pipe organs are made one at a time and for specific installations. The purchaser often gives the organ builder very exacting instructions on what sounds they want, how many manuals, even the degree of ’tilt’ on a keyboard, and countless other details, limited only by imagination, space, and finances. Additionally, the organ, being much older than the piano, has gone through many changes of what was considered necessary or even fashionable. Most organs have two manuals. While a few have only one manual, three manuals is not uncommon. Four or five manuals? Or more? Yep, they are all out there. Most modern organs have 61 notes per manual, and 32 pedals. But I have played on contemporary organs with fewer notes or pedals, playing right off the end of a keyboard during one audition. Surprise!
All of that is to say organ music must be adapted to the organ on which it is being performed. The composer may suggest a stop (a sound) that is not available on the organ being played so the performer must select a substitute. Sometimes a note originally intended to be played by the hands must now be played by the feet. This is just accepted as the way it is with organ music.
In 18th century England, most organs did not even have pedals, so music was written for manuals only. Among the composers of English organ music was Henry Heron (1730? -1795). He was the organist at the St. Magnus Church in London for 50 years. Heron’s published compositions include “voluntaries,” a term generally used to describe a piece performed on the organ. Like many 18th century voluntaries, the Trumpet Voluntary we will hear today has two sections. The first section is solemn. The lively second section also uses a contrasting stop.