Acoustics of organ pipes and future trends in the research

The pipe organ produces a majestic sound that differs from all other musical instruments. Due to its wide tonal range, its ability of imitating the sound of various instruments, and its grandiose size, the pipe organ is often called the ""king of musical instruments"" (Figure 1). The richness and variety of sound color (timbre) produced by a pipe organ is very unique because of the almost uncountable possibilities for mixing the sounds from different pipes. According to the art of sound generation, there are two kinds of pipes in the organ that are similar in function to other wind instruments: flue (labial) pipes and reed (lingual) pipes. Although this article focuses on sound excitation by flue pipes, the role of reed pipes is briefly mentioned (see Figure 2). The article also shows how the connection between sound character and pipe shape and dimensions can be understood, and it also considers the trends in the research that focus on helping organ builders in their practical work.