How Do Pipe Organs Make Music?
It starts with air...
After being pressurized by an electric blower, and stabilized by a reservoir,
air enters each windchest of the organ. Air from this windchest will flow into
individual organ pipes when two conditions are met. The organist turns on a
stop action with a draw knob or stop tablet on the console to allow a particular
rank or set of pipes to be played. Then, any keys pressed on one of the
keyboards will open note action valves allowing air to enter the pipes which
sound the corresponding notes. Most pipe organs today use electricity to
control the stop actions and note actions and are called electric action pipe
Then the air vibrates, making sounds...
Each pipe in an organ is unique, having precise length, diameter, shape,
material content, and numerous other details. The most common pipes, called
flue pipes, have a toe, a foot, and a mouth that allow air in and out of the
pipe. When the note action valve is opened at the toe of the pipe, a column of
air is caused to vibrate in and around the body of the pipe. The
characteristics of these vibrations depend on the many details of how the pipe
is designed and determine what the pipe sounds like, including the special way
that the sound starts (the attack) and stops (the decay). Other pipes called
reed pipes feature a brass or phosphor-bronze reed that vibrates as air enters
through the pipe's toe. The characteristics of the reed's vibration are
influenced and supported by air vibrating in a reed resonator, a metal column
similar to the body of a flue pipe.
In both flue and reed pipes, the column of air actually vibrates in many
different ways simultaneously, and the often complex mix of these various
harmonics or partials determine both the pitch and the rank's characteristic
sound or tone color. Within a particular rank of pipes, each pipe has common
features and proportions but every pipe is a different size. Any pipe sounds
similar to the other pipes in its rank, with the shorter length pipes having a
higher pitch. Each rank has its own tone color, and various ranks may be played
in combination with others to create the desired effect.
The sounds are made to blend...
The sound from each pipe is designed and adjusted to blend with all the other
pipes in the organ and to give the best possible results in a room. This custom
design is done by highly skilled craftsmen known as pipe voicers. The size,
shape and acoustic properties of the room, and the number of people the room is
designed to hold, are taken into account.
Every pipe makes its own sound and is in a particular position different from
every other pipe in the room. Because of these unique positions, each harmonic
vibration from each pipe reflects differently from the church walls, pews, and
so forth. As a chorus of notes are played, the sound reaching each person's
ears is very rich and complex. Often described as "thrilling" and "uplifting",
this sound is ideally suited to supporting congregational singing in much the
same way that a full orchestra supports the presentation of a musical play. The
blending of the sounds of many individual pipes into a complex chorus is a key
reason for the superiority of pipe organs over electronic organs, which are
inherently limited to relatively few loudspeakers from which the sound
Pipe organs are unparalleled custom creations for making music!
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