Celebrating the pipe organ, the King of Instruments
January 1, 2007
What is a rank, how many pipes are in a rank, and can you estimate the number of ranks an organ has by looking at just the stops?
A ‘rank’ is a set of pipes of a given color and pitch level…such as a Diapason (8′, unison pitch) or Flute (4′, octave-above-unison pitch), etc… with one pipe for each note/pitch/key on the manual or pedal keyboard.
The usual organ manual keyboard compass ranges from 56 to 61 notes (depending on whether the last upper note is G or A or C). Pedal keyboards usually range from 30 to 32 notes, though old, historic instruments may have fewer keys (that’s just the way things were…far from standardized, even today).
So a single rank played from a 61-note keyboard will include 61 pipes in graduated lengths, large to small, as the pitches ascend from low to high. In many instances, one ‘stop’ will control one ‘rank’ of pipes.
(By the way, the ‘number’ you see appended to a stop name…Gemshorn 8′ or Posaune 16′, etc…refers to the relationship of those stops to the common pitch level of the piano. The bottom note (C) of an 8-foot stop/rank on an organ will be physically eight-feet long, and the pitch at middle-C will be the same pitch as middle-C on a piano. A 16-foot rank plays an octave lower, a 4-foot rank an octave higher, etc.)
In many organ specifications you will see some stops listed with a Roman numeral…Flute Celeste II, or Cornet V…these indicating that the single ‘stop’ controls more than one ‘rank’…two, in the case of the Celeste, five in the case of the Cornet (which, just to confuse you, is a ‘stop’ made up of five flute ranks which simultaneously sound at the 8 - 4 - 2 2/3 - 2 and 1 3/5 pitch levels, creating a synthetic tone of reedy character).
If you count carefully, and the organbuilder identifies when he has ‘borrowed’ a stop to allow it to play in several places in the specification, you should be able to come up with an approximate pipe count.
Please realize that the number of ‘stops’ may not clearly account for the number of ranks. It is the number of ranks, which directly relate to the number of pipes, that create the overall sound. Theoretically, you could build an organ with several hundred ‘stops’ but only a few dozen ‘ranks’. Theatre organs, with much ‘unification’ of ranks…borrowed at multiple pitch levels and playable on several different manuals…are most likely to confuse in this area (though they still sound splendid, in their particular way).
Check our resources page and its related links for some additional background. How a pipe organ works.