Pitch and Length
The pitch produced by an organ pipe is a function of its length. Longer pipes produce lower pitched notes, while shorter pipes are higher in tone. An organ stop utilizes a set (rank) of pipes of graduated lengths to produce the range of notes needed. Stops having ranks of pipes that are sized and tuned to sound the pitch normally associated with the keys (i.e. the pitch of same keys on a piano) are called "unison stops". Other stops use pipework which is longer or shorter than that of unison ranks to speak at a fixed interval above or below unison pitch. ("octave pitch" or "mutation pitch")
The pitch of a rank of pipes is denoted by a number on the stop knob. A stop which speaks at unison pitch, or "native pitch" is known as an 8' (pronounced "eight foot") stop. This nomenclature refers to the approximate length of the longest pipe in a rank of open pipes. In a rank of stopped pipes, the lowest pipe is about 4 feet long, but because it sounds at unison pitch, it is also known as an 8' stop.
The octave sounded by a given pipe is inversely proportional to its length ("1/2 the length = double the pitch"), meaning that a 4' stop speaks exactly one octave higher than an 8' stop. Likewise, a 2' stop speaks exactly one octave higher than a 4' stop. Conversely, a 16' stop speaks exactly one octave below an 8' stop; and a 32′ stop speaks exactly one octave below a 16' stop. Octave pitch lengths used in actual organs include 64', 32', 16', 8', 4', 2', 1', and 1/2'.
Example:
Read more about this topic: Organ Stop
Famous quotes containing the words pitch and, pitch and/or length:
“Though I have locked my gate on them
I pity all the young,
I know what devil’s trade they learn
From those they live among,
Their drink, their pitch and toss by day,
Their robbery by night....”
—William Butler Yeats (1865–1939)
“It is beyond a doubt that during the sixteenth century, and the years immediately preceding and following it, poisoning had been brought to a pitch of perfection which remains unknown to modern chemistry, but which is indisputably proved by history. Italy, the cradle of modern science, was at that time, the inventor and mistress of these secrets, many of which are lost.”
—Honoré De Balzac (1799–1850)
“I have seen some whose consciences, owing undoubtedly to former indulgence, had grown to be as irritable as spoilt children, and at length gave them no peace. They did not know when to swallow their cud, and their lives of course yielded no milk.”
—Henry David Thoreau (1817–1862)