Oops, hit "reply" instead of "forward". I asked a friend of mine who is an organist about Jim's comments on organs yesterday ... here is his reply. Carleton
One might argue that organ pipes were built before the foot (the measurement, not the carbon-based life form appendage) was invented. It does not matter. The fact remains that common usage refers to the pitch of a rank of pipes as being measured by the "foot" even though every pipe of the same rank will have a different length and likely a different diameter, as well as potentially different material content. An "eight foot" rank speaks an octave lower than a "four foot" rank, and so forth up and down the scale, regardless of the real physical length or shape of the pipe. I am not aware of any organ builder who refers to and labels the various stops of the organ in meters or any other reference than a "foot." When you find one, let me know. Perhaps you can ask your builder in Quebec to produce the first "metric translation" pipe organ with the stop tablets marked accordingly. It is correct that the same pitch will be produced by a pipe of a different length that also has a different width (diameter, if round). My reference book contains a drawing (labeled a classic illustration from Audsley's works) showing 3 stopped wood pipes of different length which all speak at 256 cycles per second. Larger diameter pipes are shorter in length to produce the same pitch. All other dimensions being the same, a stopped pipe will produce a pitch one octave higher than an open pipe. My reference book also contains a table illustrating the eleven octave range of the pipe organ. It lists an 8 foot open pipe as producing the CC tone (two octaves below middle C, or typically the bottom C note of a 61-note manual keyboard). Cycles per second would be 65.41. The lowest note of this rank wold b e CCCCC, with a length of 64 feet speaking at 8.17 cycles. Working your way up, CCCC is 32 feet, CCC (bottom pedal key) is 16 feet, CC as noted is 8 feet, C is 4 feet, C1 (the 1 is shown as a superscript) is middle C with a length of 2 feet, and on up through C4 (the top manual key at 3 inches) to C7 with a length of 3/8 inch. C7 speaks at 16,744.03 cycles per second. Note the references to feet and inches, not meters and centimeters. Thus, a typical open rank of 8 foot pitch with one note for each of the 61 notes on the keyboard (no extensions down or up) will have the longest pipe about 8 feet long, and the shortest about 3 inches in length. When your French Canadian instrument is completed, ask the builder to show you the 8 foot diapason (it may be called a principal on your version). The pipe that sounds CC will be about (but probably not exactly) 8 feet in length from the lip to the open top. As noted above, it might be shorter if the pipe has a larger diameter, and its total length will have the added distance from where air enters the foot of the pipe up to the lip, or the location where the air column is broken in order to create the desired tone. You should also ask the builder about the wind pressure, and tell him/her that you do not want yours measured in inches, but rather in some appropriate metric statement of pressure. Finally, while most organists will be quite at home with pitches (and pipe lengths) of 32, 16, 8, 4, 2-2/32, and 1 foot, they also will usually use the term "meter" to describe the relative speed of the music they play on their 8 foot ranks. If you ask why to any of this, I'll respond that the reasons are "lost in antiquity," a famous Southern Pacific response to any question asking why particular speed limits were set through the town.
