STEN TERNSTRÖM & DUANE RICHARD KARNA
Choir singers and directors frequently find themselves grappling with acoustical issues that appear to affect their ability to perform well. Hearing one's own voice, for example, is crucial. It improves with increased singer spacing and depends also on the room acoustics. Singer preferences are diverse but on average one's own voice needs to be about 6 dB stronger than the rest of the choir. In most rooms this implies a fairly spread-out formation. Precise intonation may be jeopardized by pitch perception discrepancies and by mechanisms inherent to voice control but it can also be facilitated by acoustically informed measures such as articulatory enhancement of common partials. Researching such issues necessitates decomposition while remaining aware of the true complexity of the situation: that of many people singing together and hearing each other in a room.
Many people who choose to perform music as a satisfying pastime do so as choir singers. Singing in unison or in harmony with other people is a low-cost, enjoyable activity, which at the beginner's level demands little more than one's time and a certain dedication to the task.
During the past couple of decades, research into the acoustics of choir singing has uncovered numerous interesting effects that are of potential relevance to choral performance. Some concern voice production, others have to do with the acoustics of the stage and the auditorium, while still others are related to our sense of hearing. Many of them are rather subtle and, if taken in isolation, of minor importance. When the acoustical circumstances combine constructively, however, choral singing is certain to become easier; conversely, when they combine destructively, choral performance is likely to suffer. For this chapter, we have chosen to describe in detail some phenomena that we expect and hope to be particularly interesting and useful to choral directors and singers who are curious about acoustics.