ACTIONS
1998INTERACTIONS
1998
Spanish Organs
Professor Hugh Young describes himself as a "closet organist." His lifelong interest in music began at age four with piano study with his mother, a professional piano teacher. During high school he was organist in a church in his home town in Iowa. At age 18 he considered trying to make a career in music, but decided on physics instead.
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Hugh Young at the console of the organ in the Cathedral of Cordoba. The stop knobs, forming vertical rows on both sides of the keyboards, are connected through mechanical linkage to the wind chests holding the pipes. The keyboards are of wood; the "white keys" are black, and the "black keys" are white! |
In 1968, while teaching physics full time, Prof. Young enrolled as an organ major in the Carnegie Mellon Music Department, and he graduated with a B.F.A. in music in 1972. Since then he has played recitals in several local churches, and he served for four years as assistant organist at St. Paul's Cathedral in Pittsburgh.
A few years ago he presented a program of music for trumpet and organ at Trinity Cathedral, in collaboration with Randy Telfer, a recent physics-music double-major graduate of our department.
In February, Prof. Young participated in an organists' tour of Spain along with a group of organists from the University of Michigan. Members of the group presented recitals in the cathedrals of Malaga, Cordoba and Segovia.
The participants were also granted access to organs in the cathedrals of Toledo and Seville, including the famous "Emperor's Organ" in Toledo. Some of the instruments they played are nearly 300 years old.
Pipe organs provide a wealth of examples of the physics of musical sound. Most large organs include "mixture" stops (called Lleno in Spanish organs) whose pipes are tuned not to the unison pitch of a given note on the keyboard but to higher harmonics of that note, with frequencies that are integer multiples of the unison frequency. The effect is to add color and brilliance to the tone and to improve the articulation of moving voices. Mixture stops in old Spanish organs tend to be particularly brilliant.
These organs are also noted for their very assertive trumpet stops, with tapered pipes to simulate the rich harmonic content of the tones of the trumpet and trombone. The pipes are often mounted horizontally in order to project the sound directly into the room. There is nothing subtle about the sounds of these pipes; they are loud, brilliant and sometimes a little coarse, but very dramatic.
The tuning of old organs often differs from that of most modern organs (and nearly all pianos), which are tuned using "equal temperament." In this scheme, the frequency ratio of a semitone (any two adjacent keys on the keyboard) is uniformly 21/12. Because this number is irrational, this has the effect that the intervals in chords are not exactly "in tune" in terms of the ideal frequency ratios of 3/2, 4/3, 5/4 and so on. But in 1600 a more common scheme for organ tuning was "mean-tone tuning," in which some of the major thirds are tuned to exact 5/4 ratios. Music with only a few sharps or flats then sounds more "in tune" than with equal temperament, but music with many sharps or flats sounds so "out of tune" as to be unpleasant.
The facade of the organ in the Cathedral of Cordoba. Typical of old Spanish organ cases, this structure features flamboyantly elaborate carving, covered entirely with gold leaf.
