AcousticsThe effect of the environment on sounds. Indoors, the effect is caused by the materials used in construction and can range from 'acoustically dead' (no reverberation or echo) to 'acoustically live' (with a long reverberation time or many echoes). In churches, 'good' acoustics means at least one second of reverberation time and no echo. This causes musical sounds to blend together and permits good intelligibility for speaking with a minimum of amplification.
The mechanism which allows wind into the pipes when needed and shuts it off otherwise. When the organist depresses a key at the console
, only those pipes associated with that key and with the stops
in use at the time may speak. The action includes the switching which transmits the motion of the key to the chest, as well as the mechanism inside the chest that actually opens the proper valves under the corresponding pipes.
Recommendations for console dimensions and internal arrangements published by the American Guild of Organists
(AGO). These are based on a consensus of organists, and when followed by organ builders result in consoles that are similar. This reduces mistakes and uncertainty when an organist moves from one instrument to another. Most builders try to follow these standards. A copy of these recommendations in PDF format can be found here.
of the organ placed at a distance from the main organ and the console
, permitting echo-like effects. Named from 'antiphon', or liturgical verses recited alternately by clergy and congregation. Can also be called ECHO
The enclosed, motor driven fan that provides wind under pressure for the organ pipes. The noise generated by the blower is best kept to a minimum by placing it in a sound-resistant enclosure or by locating it remotely from the organ.
Pipes that can be played by more than one stop
control all are called Borrows or Borrowed stops. They duplicate other stops elsewhere in the organ, and permit a single rank of pipes to sound in more than one division
. Borrows usually involve softer accompanimental ranks
and Reed ranks, and are provided to increase the flexibility of smaller organs.
CELESTEA rank of pipes, tuned slightly off unison with another similar rank in the same division, and intended to be sounded with its partner rather than as part of larger combinations. When properly tuned (1 -7 beats per second) this combination produces an undulating sound reminiscent of the effect of string instruments playing in unison. Celestes work best using stops with soft and bright Timbres.
In the organ, the wooden boxes on which the pipes stand. These are usually rectangular, are filled with wind under pressure, and contain part of the mechanism (action)
which allows wind into the proper pipes, causing them to speak as directed by the organist at the console
CHIFFPart of the attack, or very first instant of speech, of a flue pipe. It is a clicking, consonant-like sound that serves to mark the entrance of each note in a moving passage. Chiff can be adjusted in voicing from being a very prominent part of the pipe's speech to being completely inaudible. It is often called articulation, and when not excessive it increases the clarity of polyphonic music.
A grouping of pipes played from the bottom manual
of a 3-manual organ, normally enclosed
, and thought of either as subordinate to the other divisions
and intended to accompany the choir, or as a locale for solo stops
that can thereby be played separately from other divisions
(or Combination Action): A system of thumb and toe buttons (pistons) which permits the organist to pre-set combinations of stops
on the console
and then, by pressing the appropriate button, to bring the preset combinations into action instantly. The settings are stored in a memory and remain available indefinitely, until changed at the console.
The work station for the organist. It consists of a cabinet containing the manual
keyboards and the stop
controls, arranged in a convenient and standardized manner as prescribed by the American Guild of Organists. There is a bench for the organist, and parts of the organ action are found in the cabinet. The console is usually separated from the rest of the organ, to which it is connected with a cable, and is often decorated with cabinetwork that matches the decor of the church.
Controls in the console
which connect together the various keyboards, so that while playing upon one, the stops
drawn upon another also sound (INTER-couplers, e.g. Swell to Great); or transferring the played keys upward or downward an octave on the same keyboard to increase the range or shift the register of the stops drawn (INTRA-couplers, e.g. Swell to Swell 4'). Couplers permit the greatest possible number of combinations of stops and, in effect, extend the reach of the organist's hands and feet.
A pedal which, when gradually depressed, brings on all or most of the stops
of the organ progressively beginning with the softest. If pressed down gradually while playing, it produces a crescendo effect. If then gradually retracted, it produces a diminuendo effect until the registration returns to the actual stops drawn. The Crescendo pedal does not move the stops and has a warning light to indicate when it is engaged.
(also spelled ZIMBELSTERN): A series of small bells, usually high-pitched and not tuned to specific intervals, which ring in a random sequence when activated. It adds a festive sparkle to larger registrations and is used on joyous occasions. Some have a decorative star that rotates while the bells are ringing, hence the name (Stern, German for star).
separated from the rest of the organ, rather than built into the organ case. A detached console permits the most convenient location for the organist, not only for hearing the organ itself, but for conducting the choir and for seeing into the church without needing a mirror.
DIRECT-ELECTRIC™ is a trademark of the Wicks Organ Company of Highland, Illinois. It refers to their all-electric system for controlling the organ, and includes patented electro-magnetic pipe valves in the chests
and the entire switching system that routes the electrical impulses from the keys to the proper valves. This was developed prior to 1920 and has been greatly refined since then. It eliminates both the periodic releathering required by the electro-pneumatic system, and the limitations of the mechanical connections of the tracker system.
Sections into which the pipes of an organ are divided, which are played from different keyboards. This permits contrasting tonal colors from the various keyboards, allows stops
to be used for solos with different stops for accompaniment (when playing on two keyboards), and permits quick changes in registration by shifting from one keyboard to another.
A type of control in the console
for turning on stops
. It is like the original mechanical type of control, in which a knob on the end of a shaft was pulled to turn the stop 'on' and pushed to turn it 'off.
The modern type is electric, and except in very small organs, they are usually arranged on either side of the manual
keyboards on panels called Side Jambs
, arranged for the organist's convenience.
A term describing pipes placed horizontally instead of vertically, and often projecting from the front of the organ case. This method is generally used for powerful reeds, like Trompette en Chamade, whose tone becomes more intense and penetrating through such placement. (Chamade: a military signal intended to be heard in the enemy camp).
This means that the organ (or a division
, if it is used to describe only one division) has its pipes inside one or more wooden cabinets or Cases, which consist of sides, back and top. Their resonance serves to refine and blend the sound and project it into the room, providing an ideal environment for development of the tone. Such cases, sometimes called reflective cases, can be very decorative, and often have a facade of large pipes across the front.
described as 'Enclosed' refers to the pipes located in a wooden enclosure, or organ chamber
, fitted on the front with adjustable louvers or Swell shades. The volume of sound from the enclosed division is controlled by opening and closing the shades. For reasons of clarity, not all divisions of an organ are ordinarily enclosed.
This describes pipes that are located so as to be visible, not encased
. Exposed pipes give the organ tone brightness and clarity, illustrating the rule that what can be seen in the room can also be heard best in the room. In modern organs at least the Great
is generally exposed, to help overcome the somewhat distant effect of the enclosed divisions
. Exposed pipes are frequently employed as a decorative facade for the organ.
Pedals used by the organist to manipulate the adjustable louvers or Swell Shades with which enclosed divisions
of the organ are provided. The shades increase or decrease the volume, enabling the organist to give expression to the division or to adjust the volume of solo stops
Additional pipes, added to the top or bottom of a rank, to permit using the same rank at more than one pitch. For example, the usual 8' rank has 61 pipes, one for each key on the manual
; the largest pipe is 8 feet long, and the pitch sounded on each key is the same as that of the piano (8', or unison, pitch). A pitch one octave higher than unison (4' pitch) can be sounded from the same rank by starting with the lowest key of the manual playing the 13th pipe and so on upward; at the top of the rank a 1 2-pipe extension must be added to complete the compass of the manual.
FREE STANDINGThis describes an organ which is entirely self- contained in its own case. It is supported on its own pedestal and depends on the walls of the room only to keep it steady. Its case is free to resonate on all sides and on top. This type of installation provides the best blending of sound and the most effective projection into the church.
(See Combination Pistons
) Pistons which affect all stops
in the organ. These are distinguished from Divisional Pistons, which affect only the stops in their respective Division
. With a General Piston, the registration in all Divisions can be changed instantly; with a Divisional Piston, a change can be made in one Division without affecting the stops in another.
A grouping of pipes, normally not enclosed
, played from the bottom manual
of a 2-manual organ (or the middle manual of a 3-manual organ). It includes the loudest and brightest ranks
of the Principal family, intended for accompanying congregational singing, and usually also contains a chorus of Flutes and often Reeds as well.
JUNCTION BOARDA panel with rows of connectors, used for splicing multi-conductor organ cables, or for adapting existing chest cables with cotter pin terminals to modern relay terminals without having to re-form the ends of the cables.
Keyboards in the console
, designed to be played with the hands, as opposed to the Pedal
keyboard, which is to be played with the feet. Manual keyboards resemble those of a piano, but normally have only five octaves (61 notes), beginning with C, two octaves below Middle C. Having more than one Manual makes possible quick changes in registration (by moving from one Manual to another) or solo effects with accompaniment (by playing on two Manuals at once).
The original system for connecting the console
to the rest of the organ. In its purest state, all parts are mechanical: 'trackers' and other parts connecting the keys and valves under the pipes, 'sliders' and drawknobs
to turn stops
on and off, mechanical couplers
between keyboards/ and mechanical connections between expression pedal and louvers. This system is also called 'Tracker Action'. It promotes a compact arrangement of the parts of the organ but it limits console placement and is not adaptable to every situation.
MIDIAn acronym for Musical Instrument Digital Interface, a system of encoding signals from a keyboard and sending them through standardized connectors, so that electronic keyboards, synthesizers and other devices of various manufacturers can be interconnected. The pipe organ too can be equipped with MIDI output connectors; this enables the organist to control other instruments from the organ.
consisting of more than one rank of pipes. Some, with high pitches corresponding to various harmonics or overtones of the notes on the keyboard, are used with 8',4' and 2' stops to produce a brilliance and grandeur. These are especially useful in accompanying congregational singing. Others, lower-pitched, are solo stops when used in small combinations.
A system dating back to the days of Thomas Edison and used to allow a single telegraph wire to transmit more than one message at a time. The modern equivalent can transmit the many signals from an organ console
to the relay over a single small cable. Not yet widely used in this way because of occasional problems with long cables, multiplexing can also be used inside the console, where it allows unlimited couplers
utations are stops
that add specific harmonics to color the organ chorus sound. Mutations are usually indicated by fractional length, such as 2 2/3, 1 3/5, 10 2/3.
A room in a building, designed to contain all or (preferably) one division
of an organ. Window-like openings between the chamber and the auditorium project the sound; these are usually backed with Swell Shades to allow the organist to increase or decrease the volume. The sound issuing from such tone openings is only a fraction of the total, causing divisions so located to sound somewhat muffled and distant. It is better to avoid using a chamber by putting the enclosed
division in a Swell box.
he valve under the pipe in the chest, which admits air into the pipe, causing it to speak when the key is depressed. With Mechanical Action the pallet is opened by a rod or tracker connected to the key, and feeds air into a channel supplying all pipes of the corresponding note on that chest. With DIRECT-ELECTRIC™ Action
it is opened by an electromagnet when the key is depressed, and there is a separate pallet for every pipe, assuring an adequate supply of wind to each pipe no matter how many are played at once.
PEDAL or PEDALBOARD
A keyboard in the console
, designed to be played with the feet. It resembles the manual
keyboard, with sharps and naturals, but larger. Like the manual keyboard, it starts at C two octaves below Middle C, but normally has only 32 notes. Every organ has a Pedal, as it is needed to play the bass parts in organ literature.
PIPE RACKA horizontal board located above the pipe chest, solidly fastened to the chest or to an adjacent vertical surface, and in line with a given set of pipes, used to support the larger pipes by means of ties or hooks. It also prevents accidental overturning of pipes during tuning and helps keep reed pipes in tune by reducing their tendency to move from vibration.
Decorative wood carvings or grilles located at the tops of groups of facade pipes (called 'flats' or 'towers') in organ cases to conceal the true length of the pipes and eliminate asymmetry between groups of unequal length. These are generally attached to a cornice which forms the top of the case, behind which the facade pipes extend. Occasionally, pipe shades are placed behind the facade pipes to conceal a void between the tops of the pipes and the top of the case.
The sound-producing elements of the organ, which distinguish it from all other musical instruments. Each pipe produces a single tone, and it takes a series of them, one per key, to play the entire gamut of the keyboard. Such a series is called a Rank, because the pipes are usually arranged in a row for mechanical reasons. Pipes are of two classes: flue pipes, with no moving parts except the air, like a whistle; and reed pipes, which have a vibrating tongue producing the tone and a resonator to modify its quality.
Valves, such as pallets
below pipes, that are opened by air under pressure. This is accomplished by means of leather pouches or membranes, called 'pneumatics,' which move by flexing when the pressure on the two sides of the leather is unequal. Action
systems incorporating pneumatic valves have a major weakness in the relatively short life of the leather, which needs periodic replacement, a costly operation known as 'releathering.'
A grouping of pipes similar to the Great
division in that it is normally not enclosed
, but of considerably lower dynamic level than the Great. Usually used in combination with, or in place of, the Choir
division, and like the Choir normally played from the bottom manual
of a 3-manual organ. The positiv is frequently located in a case separate from other divisions
, and when located behind the console
is called RUCK-POSITIV.
RACK BOARDThe thin board with holes located immediately above, and parallel to the top board, supported by wood blocks and dowels. Rack boards are used to support pipes in their proper vertical position on the chest and prevent them from moving or rattling.
RANKSRows of pipes graduated in length, one per key, corresponding to the entire compass of the keyboard. Each Rank has a different tone color or pitch, and providing multiple Ranks in an organ allows many different combinations, resulting in a great range of volume and tone quality. Ranks are described according to the length of the largest pipe, corresponding to the lowest key ( 2 octaves below middle C), as 16',8',4', etc.
The device which provides low voltage direct current (DC) for the operation of the electrical part of the organ action
. It incorporates transformers and diodes and is connected to the same power source that operates the blower
. Older organs had DC generators, which required periodic maintenance. Rectifiers, as a rule, are trouble-free and need no attention.
A device used to control air pressure into the pipes. Quick response and accurate regulation are essential if the organ tone is to be steady and unwavering, and various kinds have been used over the years. Bellows with leather folds and movable lids were the first to be used successfully, and today Schwimmers
ore in common use.
Relays are the switching devices that direct the organist's movements at the console
to the appropriate pallets
, so that pipes will sound which correspond to the stops
and keys activated at the console. They include switches, which in modern organs are transistorized so there are no contacts and no moving parts, wiring and connectors. Organs with Mechanical Action
do not have Relays, mechanical linkages doing all the work.
When a sound is produced in a room, and then stops
, the ear does not normally perceive a sudden silence. There may be a gradual decline in sound, or there might be one or more echoes, all caused by reflections of sound from the inner surfaces of the room. When sound gradually decays, the effect is called 'reverberation and the length of time it takes a loud sound to die away completely is called the 'reverberation time.' Reverberation times of 1 second or more are necessary in churches. Echoes, that is, quiet periods followed by recurrences of the former sound, destroy speech intelligibility; they can be avoided by proper room design.
Any control on the organ which activates an automatic function when depressed, and 'reverses' or stops
that function when pressed again. Commonly used to engage and disengage couplers
, or to turn on or off things like Sforzando
. They can be in the form of thumb pistons
or toe studs
A type of pressure regulator
that is usually attached to the bottom of a chest
and regulates the wind pressure by means of a movable lid controlling an inlet valve. When wind is consumed in the chest, the lid moves inward, under the tension of springs, and opens the inlet valve, admitting air from the blower
. If the lid is large and the springs of the proper type, this kind of regulator produces the most stable wind pressure.
A control providing a quick way to get 'full organ,' without upsetting stops
drawn in the usual way. Usually a reversible, the Sforzando when activated turns on all of the stops and couplers
of the organ instantly, without moving the stop controls, and when activated again, restores everything to the way it was before. Also labeled Tutti, or Full Organ.
Vertical panels at each side of the manual
keyboards in the console
, on which the stop
controls (in the form of drawknobs
) are arranged by divisions
. Sometimes all the couplers
are included, often only the infra-couplers, with the inter-couplers on another panel (the tablet board) above the top keyboard. The side jambs are set at an angle for easy access to the drawknobs.
These are used in mechanical action. They contain the key channels or grooves into which wind is admitted when keys are pressed; above each channel are all the pipes corresponding to that key. Between the key channels and the pipes are the sliders, movable perforated boards connected to the drawknobs
. These open or close the passages leading to the individual pipes, arranged in ranks
along the length of the chest
. Each pipe will speak only when its key is pressed and when its slider is in the 'on' position. These chests can also be used with electric 'pull-downs' or magnets that open the pallets
electrically: in that case the key action is electric even though the stop
action (via sliders) may be mechanical.
SOLID STATEThis term came into use to describe transistors, which when first invented were used to do things that had previously been done by vacuum tubes. In tubes the electric current is transmitted through a gas at a very low pressure; in transistors it is transmitted through a solid, hence the descriptive name, 'solid-state devices.' As commonly used, solid-state means using transistors and diodes, rather than vacuum tubes or relays and contacts.
A grouping of pipes similar to the Swell division, although normally containing only solo stops
in place of chorus stops
and played from the topmost manual
of the console
. Generally found only in very large instruments.
A type of control in the console
for turning on stops
. It moves up and down, and when down the stop or coupler is 'on.' These usually protrude from a panel above the top manual
keyboard, arranged in one or two horizontal rows. Once popular because they bring all the controls close together, they are now used mostly for smaller organs. Sometimes called stop tablets.
A stop is an individual voice in the organ, composed of one or more ranks
of pipes. Its name includes a number, like 16',4', etc., which designates its pitch according to the length of its largest pipe (corresponding to low C on the keyboard). If it includes more than one rank of pipes it is a Mixture
, with a Roman numeral in front of its name to indicate the number of ranks, as III or IV. The word stop is also applied to the control in the console
which turns on the actual stop. The name comes from the original controls, which were introduced to shut off, or 'stop' some of the ranks so they did not all play at once, as they did in the earliest organs. See the Encyclopedia of Organ Stops
for a information on specific stops.
A grouping of pipes located in a chamber
or an enclosure equipped with Swell Shades, or movable louvers covering tone openings, which enable the organist to make the tone 'swell' or get louder, when desired. It is played from the top manual
keyboard of a 2- or 3- manual console
. The Swell contains stops
to accompany the choir, and louder voices that benefit from the expression afforded by the Swell Shades, usually including a chorus of reeds.
or EXPRESSION SHADES: Movable louvers, normally vertical, which cover openings in chamber
walls or in expression enclosures and which the organist can open or close with an expression pedal at the console
. This arrangement allows the tone to be shaded, louder or softer, and affects all the pipes located within the enclosure. At least one unenclosed division
is desirable to provide a contrast to the somewhat indirect sounds from the enclosed
The panel above the top manual
keyboard in the console
, in which the stopkeys or tilting tablets which control some or all of the stops
TEMPERAMENTThe tuning scheme according to which the intervals between half-tones are adjusted to permit a variety of chords to be played on a keyboard instrument. Various temperaments have developed over the years some of which favor some chords at the expense of others. The most common is 'equal temperament' with each half- tone of equal size.
A type of rocker switch in the console
for turning on stops
. When pushed in at the bottom the control is ON, and when pushed in at the top it is OFF. These switches are located in the tablet board above the top manual
Knobs normally located directly above the pedal
keyboard that can be pressed with the feet, to activate reversibles
or combination pistons
. They are useful for making changes in registration while playing at times when using a thumb piston might be awkward. Toe pistons frequently duplicate the functions of thumb pistons.
The process of going over the voicing
of an organ after the installation is completed and every detail of the building is in its final state. Every pipe is checked, to rectify any irregularities caused by handling, by the location of the individual pipes or by the acoustics
. The needed adjustments are determined by listening in the auditorium while there are no distractions.
An opening through the wall of an organ chamber
, communicating with the church, often covered with, but organs so located also need an exposed
The top surface of each chest
is covered with Top Boards, on which the pipes stand, each over a hole drilled through the top board. Inside the chest is the mechanism (action
) to admit air into the proper pipes. With DIRECT-ELECTRIC™ Action
this consists of magnetically-operated valves; each covers a hole in the Top Board, and uncovers it when the key corresponding to its pipe is pressed, allowing air to enter the pipe and bring it to speech.
A method of imitating the keyboard feel of mechanical
(or 'tracker') action. Because mechanical action includes a direct connection between key and pipe valve, there is a resistance when the key is first moved, followed by sudden relaxation, the 'pluck' caused by the action of the air in the chest
on the valve. Tracker Touch provides the 'pluck' through springs or magnets mounted on the keys.
TREMULANTA mechanical device used to provide an undulation in the tone of the organ, through a rapidly-recurring slight raising and lowering of the wind pressure. Both pitch and volume change in a regular rhythm, reminiscent of the 'vibrato' employed by instrumental players.
The process of adjusting each pipe in the organ to the correct pitch. This is done by changing the length of each flue pipe, using various means such as tuning slides
, caps, etc; and the length of the vibrating tongue of each reed pipe
by means of a tuning wire. Since the pitch is affected by the temperature of the air in and around the pipes, the tuning fluctuates with temperature changes, and must be re-done periodically if the organ is to sound at its best.
Cylindrical or conical extensions of the body of open pipes, made adjustable to permit tuning the pipes. They are adjusted during tuning, and fit tightly enough so they will not move if undisturbed. They can be made of decorative material for exposed
Unification is using a rank of pipes to play either at more than one pitch or on more than one keyboard. Each stop
providing one of these features is called a unified stop, the rank is called a unified rank, and an organ containing all or mostly such ranks
is called a unit organ. Unification is more practical with non-mechanical actions, and when carried too far results in loss of clarity.
VOICINGThe process of adjusting the various parts of a pipe so as to produce the desired tone. There are three aspects to the tone, which need to be correct and consistent from one pipe to the next in the same rank. They are the attack, or the very first instant of speech; the tone quality, or color that distinguishes one kind of sound from another; and the volume, or strength of the tone, each judged strictly by ear.