Along with the fundamental wave briefly described above, harmonics or overtones are also formed in the organ pipe. Thus in an open pipe, we observe the second harmonic whose frequency f=V/L. In the case of an 8' pipe we would get the 64 Hz fundamental plus a second harmonic of frequency 128 Hz. Similarly third and higher order harmonics all add to the richness of the sound.
As a general rule of thumb, the narrower the pipe, the more harmonics it will have, and the wider the pipe, the fewer harmonics it will have. Straight pipes also have more harmonics than tapered pipes. So an organ builder has plenty of things to change to make different sounds: tube shape (straight, tapered), whether is it stopped or not, and pipe material composition.
Appendix B. Air Chest -more later.
Appendix C. Organ Divisions for the Village Church Organ
Allen R-465 Digital PEDAL GREAT SWELL CHOIR SOLO STRING |
Pipes new exposed Great - old pipes reconfigured 32 Resultant 16 Violee de Gambe 4 Diapason 16 Trompette 8 Trompette 16 Montre (Swell) 16 Flute Bouchee 2 2/3 Nazard 16 Viole de Gambe |