Glossary of Terms Related to the Oaxaca Organs

Accessory stops - Special effect stops found on most table organs up to the mid-18th century. Most common are the drum (Sp. tambor) and little birds or nightingales (pajaritos); also known as toy stops. (Sp. registros de adornos o accesorios).

Bajo - The lower half of the keyboard.

Bellows - Apparatus separate from the organ which collects and distributes air to the windchest. The structure and pleats are made of wood; the pleats are joined by hinges of sheepskin or leather. The topboard is raised manually and lowers freely, creating a determined wind pressure from stone or lead blocks encased in or attached to the topboard. The most common forms are wedge or fan bellows (fuelle de cuña, fuelle de abanico). Reserve or horizontal bellows (fuelle de reserva) with parallel pleats appear in the late 19th century, especially with organs built in Puebla. 

Blower - An electrically powered turbine that feeds a steady wind supply to one of the bellows enabling the pipes to sound. (Sp. ventilador)

Channel board - A thick wooden block perforated with channels and sealed usually with sheepskin.  which was set vertically against the front interior of the organ. It was connected to the windchest and distributed air to the offset toeboards of the façade and clarin pipes.  In the late 19th century the channel board was replaced by the more streamlined system of offset tubing, particularly in organs built in Puebla. (Sp. tablón acanalado)

Compass - The number and extent of the keys in a keyboard. (Sp. extensión)

Disposition - A list of the stops and compass of the organ. (Sp. disposición)

Divided registers - Wind chest construction typical of Iberian baroque organs from the 17th century onwards. The sliders are divided at middle c’/c#’ and may include non-parallel stops on either side. The lower bass half of the keyboard extends from middle c and below (Sp. bajo, baxo) and the upper soprano half from c# and above (Sp. tiple). Each half is controlled by stop knobs (stationary organs) or slider pulls (table organs) on either side of the keyboard, allowing the organist the possibility of choosing a different sound for each hand. The sliders of the highest registers of some 2´ table organs are divided b/c’ even though the toeboards above them are divided c’/c#’. (Sp. medio registro, registros partidos)

Flue pipes - The basic component of pipe organs, which includes the principals and stopped pipes of metal or wood. The pipe sounds when wind is directed through a narrow opening in the conical foot of the pipe to strike against the lip of the mouth, which is then enhanced by the body of the pipe. The pitch and color of the sound is largely determined by the width and height of the mouth and the length and width of the body of the pipe. (Sp. tubos labiales)

Foot - Measure of the speaking length (from mouth to top) of the longest principal pipe used to categorize organs and determine its pitch. Large Oaxaca organs are eight-foot (8´), medium are four-foot (4´), and small are two-foot (2´); an eight-foot pipe sounds at unison pitch, a four-foot pipe an octave higher, a two-foot pipe two octaves higher. (Sp. pies) 

Hips - Rounded protuberances on the sides of the lower case of Oaxaca-built stationary organs, distinguishing them from organs with straight sides built elsewhere in Mexico. Hips on organs are documented from the early 18th to late 19th centuries but probably originated earlier. Their purpose seems to be decorative rather than functional, although they may have provided ballast for stability during earthquakes. Hips may be integrated into the lower case construction or hung on the sides, symmetrical or with a high bulge, small and merely symbolic or extravagant; their profile may be repeated across the façade as a decorative feature. (Sp. caderas)

Horizontal trumpets - A rank or ranks of reed pipes projecting horizontally from the front of the case above the key desk, characteristic of stationary Iberian-style baroque organs. An 8´ rank of trumpets usually corresponds only to the soprano half of the keyboard; a 4´ register is often substituted in the bass half (bajoncillo) because of the unwieldy length of the lowest 8´ pipes. In rare cases the bajoncillo may stand inside the case because of design constraints (e.g., Tlacochahuaya). (Sp. clarines, Fr. en chamade)

Key action - The keys are connected by wooden trackers to the pallets or valves in the pallet box at the base of the wind chest which open to admit air from the wind chest into the pipe. Pressing the key opens the pallet by means of a spring and releasing the key shuts it. The suspended trackers may be directly connected to the pallet box or indirectly by means of a roller board. (Sp. mecánica del teclado) 

Key desk - The recessed square around the keyboard. Some stop knobs may be set along the sides of the key desk, apart from those in the façade of the organ. (Sp. ventana)

Lip - The upper or lower edge of the mouth opening in a flue pipe. In Oaxaca organs the decorative field around the upper lip is either rounded or pointed (Gothic). (Sp. labio) 

Mechanical action: Key action in which the keys are connected by wooden trackers to the pallets which open to admit air from the wind chest into the pipe; pressing the key opens the pallet and releasing the key allows it to shut by means of a spring (Sp. tracción mecánica).

Mixture - A register with multiple ranks of the same scale. Roman numerals indicate the number of ranks of pipes involved, such as Lleno IV. Mixtures are rare in Oaxaca organs, although the term was used in 18th and 19th century contracts to designate a stop. (Sp. mixtura)

Offset tubing - Round conduits of pipe metal which conduct wind from the windchest to the toeboard of pipes in the façade. Their function was similar to that of channel boards, but more efficient and less cumbersome. Offset tubing is apparent in late 19th century organs built in Puebla, but rare in Oaxaca organs. (Sp. Conducto de metal o tubo desviado)

Pallet - A valve in the wind chest of the organ which is opened to admit air to the channel of a particular note. The air then passes to the pipe depending on whether the corresponding slider is in open or closed position. Each pallet is connected to its corresponding key by a tracker and is opened by pressing the key. (Sp. ventilla)

Pallet box - The structure at the base of the chest which stores the wind under pressure and houses the row of pallets. (Sp. arca de viento)

Pipe - The basic phonic element of the organ (Sp. tubo). Wind is blown through the pipe to produce the sound of a single note. The two basic types are flue pipes (Sp. tubos labiales), open or stopped (covered at the top), which may be of metal or wood, and metal reed pipes. (Sp. lengüetas)

Pipe shade - Decorative wood carving which fills in the empty space above the groups of façade pipes and prevents them from falling forward. (Sp. celosía)

Pitch - Based on the frequency of a above middle c and in relation to modern pitch which is a=440 Hz, Oaxaca organs were pitched low, the a at either 392 or 415 Hz approximately (hertz or frequency of vibrations). This means that C on the organ actually sounds like Bb (392 Hz) or B (415 Hz). Pipes were later modified, (i.e., the tops were cut to shorten them) in the late 19th or early 20th century, to raise them to modern pitch. (Sp. diapasón)

Principal - The register with the fundamental sound of the organ on which all the succeeding registers are based. The pipes of the principal register are arranged in the façade of stationary organs; these may be 8´ or 4´ depending on the size of the case. (Sp. flautado mayor)

Rack board - A thin horizontal perforated board, often covered with sheepskin, placed on wooden supports to stand above the toeboards. It holds the pipes in place on the chest and prevents them from falling over. (Sp. panderete)

Reed pipe - An organ pipe whose sound is produced by a vibrating metal tongue modified by a resonator, the upper slightly conical body of the pipe. (Sp. lenguetas)

Register - A specific row or rank of pipes (Sp. hilera) which produces a homogeneous sound. (Sp. registro)

Registration - The art of choosing and combining stops to produce the desired sounds that will properly enhance the music being played. (Sp. registración)

Roller board - A covered wooden vertical panel above and behind the keyboard of stationary organs, with a series of horizontal wooden rods or rollers (Sp. molinete) connected to the keys by trackers. It transfers the movement of the keys to the pallets of the wind chest. It may either face forward toward the organist or backward toward the interior of the organ. (Sp. tablero de reducción) 

Scaling - The relationship between the diameter of a pipe and its length. Wide-scaled pipes produce a stronger fundamental tone, while narrow-scaled pipes produce a higher harmonic development. Oaxaca organs tend to be comprised of flue pipes of a principal scale of average width. In stationary organs the 8´ bardon is usually wide scaled. (Sp. escala, medida, mensura)

Short octave - Keyboard design typical of the 15th to mid-19th century in which the lowest octave of the keyboard is not chromatic but is shortened by the omission of C#, D#, F#, and G#. To the modern eye, it looks as if the keyboard begins at E rather than C. However, the E corresponds to C, F# to D, and G# to E. (Sp. octava corta). 

Slider - A perforated wooden slat in the wind chest which is connected to the mechanism of the registers. It slides back and forth to allow or prevent air from entering the row of pipes above it, based on whether its holes are aligned with those of the wind chest below and the toe boards above. In stationary organs, registers are selected by pushing and pulling the stop knobs or in some cases levers on the façade; in table organs, the ends of the sliders protrude from the sides of the case and are similarly pushed and pulled. (Sp. corredera)

Stationary organ - Instrument in fixed position with an 8´ or 4´ principal. It may be positioned on the floor or set on wooden planks or a cement base. The stop knobs are usually on the façade but sometimes on the sides of the organ. (Sp. órgano estacionario, órgano fijo)

Sticker or pin action - Key action typical of 18th century Oaxaca table organs and a few 4´ stationary organs. When a key is depressed, it pushes on a wooden rocker or backfall which splays out from under the keyboard and serves the function of a horizontal tracker. These push on small wooden pins to open the appropriate pallet. (Sp. tracción de balancines)

Stopped pipe - A flue pipe made of either wood or metal which is sealed at the upper end. Wooden square or rectangular pipes usually have a movable stopper which can be adjusted for tuning purposes. Metal stopped pipes are sealed with a disc of the same metal, soldered on top and tuned by adjusting the large ears on either side of the pipe mouth; they include the 8´ bardón and the 4´ tapado or tapadillo.  (Sp. tubo tapado)

Stop - A register of the organ. (Sp. registro)

Stop action - Mechanism which moves the sliders, allowing air to flow from the windchest into the chosen rank of pipes or register. On stationary organs the stops or register draws are finished with turned knobs (Sp. pomos). They are connected to interior trundles which rotate to move the slider of the desired register to open position. On table organs the action is direct by pushing or pulling the ends of the sliders protruding from the sides of the case; on Oaxaca organs the “on” position is always pushed. (Sp. mecánica de registros)

Table organ - 2´ or 4´ organ which sits on a table with its bellows behind; the ends of the sliders for controlling the stops protrude from the sides of the case. The smallest Oaxaca organs were originally used in processions, but by the 18th century most were in fixed positions. 4´ organs were too heavy and cumbersome to ever be carried in processions. (Sp. órgano de mesa, órgano portatil)

Temperament - System of musical tuning that sets the intervals between half tones of the octave throughout the compass of an organ in order to favor certain keys over others. Meantone temperament (Sp. temperament mesotónico) is common in Oaxaca organs into the 19th century. 1/4 comma meantone temperament is the purest in terms of frequencies and the most restrictive in terms of which major and minor keys can be played. 1/6 comma has less of an “edge” and allows the organist to play in more tonalities. Around the mid-19th century the temperament began to shift toward equal temperament in which each half tone interval is equal and all tonalities may be used. (Sp. temperamento igual)

Tiento - (tento Portuguese) – The predominant Iberian musical form for organ composition from the late 16th to 18th centuries. It is equivalent to a “work” or simply a “piece.”

Tiple - The upper half of the keyboard. 

Toeboard - A long pierced wooden board which sits above the sliders and covers the top of the wind chest. The toe or foot of a pipe stands in each beveled hole and is held firm and prevented from falling over by a pipe rack. The rows of holes correspond to the rows of pipes. (Sp. tapa)

Tracker - A long thin vertical piece of wood, usually rounded (Oaxaca organ-building) or rectangular (Puebla organ-building), which connects the key of an organ to its pallet, either directly or via a roller in a roller board. Pressing the key opens the valve to admit air to the pipe. (Sp. varilla)

Tracker or mechanical action - Key and stop action inside the organ operated by mechanical means. (Sp. tracción mecánica)

Trundle - A rotating wooden hexagonal rod with arms which transfers motion from the draw stop to the slider. (Sp. molinete de registro, árbol giratorio)

Tuning - The adjustment of each pipe to sound at the correct pitch. Open flue pipes are tuned by flaring out or bending in the open top of the pipe with a tuning cone or by raising or lowering the tuning slide or roll, thus modifying the length of the pipe. Metal stopped flue pipes are tuned by adjusting the ears (Sp. orejas) on the sides of the mouth; wooden pipes are tuned by adjusting a stopper at the top; and reed pipes are tuned by adjusting the length of the tuning wire. (Sp. afinación)

Voicing - The process of adjusting the various parts of a pipe in order to produce the desired uniform sound. Pipes in the same rank must be consistent in their attack (the first moment the pipe sounds), the tone quality or color, and the volume or strength of the tone. Voicing is the final, most complex and artistic step in organ-building or restoration and provides or restores to the organ its particular tonal character. (Sp. armonización). 

Wind chest - The wooden box inside the organ with wide and relatively shallow dimensions cut through with tone channels. The pallet box at its base stores the wind from the bellows under pressure and distributes it to the pipes, according to the stop selected and the key pressed. The sliders and toeboards are arranged on top of the pallet box. (Sp. secreto)

Wind trunk - A large wooden square or rectangular conduit which conveys the wind from the bellows to the wind chest. (Sp. portaviento, tronco de aire)