Over the course of 1,000 years, four different types or families of organ pipes emerged: (1) Principals, (2) Flutes, (3) Strings, and (4) Reeds. The families are distinguished by the timbre or quality of sound they produce, as well as the manner in which they are constructed.
THE PRINCIPAL PIPES
The "principal" pipes are usually made of a metal alloy with a medium-scaled diameter compared to the relative length of the pipe. The "timbre" or tone-color a Principal is a sound that is unique to the pipe organ alone, in other words, that it does not imitate the sound of any other instrument.
LISTEN
Listen HERE to Dr. Ben Keseley demonstrating the Principal pipes of Martin Pasi's Opus 28 at St. George's Episcopal Church in Arlington, Virginia. These are among the kinds of sounds we will hear from the new St. Michael organ when it is finished.