Flue pipe
Encyclopedia
A flue pipe is an organ pipe
that produces sound through the vibration of air molecules, in the same manner as a recorder
or a whistle
. Air under pressure (referred to as wind) is driven down a flue and against a sharp lip called a Labium, causing the column of air in the pipe to resonate at a frequency determined by the pipe length. See wind instrument
. Thus, there are no moving parts in a flue pipe. This is in contrast to reed pipe
s, which are driven by a beating reed, as in a clarinet
. Flue pipes are common components of pipe organ
s.
A flue pipe has two major parts, a foot and a resonator. The foot is the bottom portion of the pipe, usually conical. At its base is the toe hole, through which wind enters it. The length of the foot does not affect the pipe's pitch, so organ builders vary the foot lengths of their flue pipes depending on other factors, including the desired shape of the pipes in the façade, the height of the rackboard in which the pipes are seated, and the weight of the completed pipe.
The resonator supports the oscillations of air generated at the mouth of the pipe, a horizontal opening at the juncture of the resonator with the foot. The voicing, the length of the resonator, and the resonator's volume all determine the fundamental pitch of the flue pipe. The conical taper of the pipe determines the overblown pitch. If the pipe is metal, a tuning sleeve or tuning collar may be fixed at the top of the resonator and raised or lowered to vary its length, thereby adjusting the pitch produced.
Between the foot and the resonator, the side of the pipe containing the mouth is flat. A plate of metal or wood called a languid, fixed horizontally here, blocks the airway, except for a small slot called the windway alongside the mouth. This allows air to flow as a sheet of wind directed towards the pipe's mouth. Flat pieces of metal or wood called ears may be attached to the sides of the mouth for tuning purposes, and a horizontal dowel called a roller or beard may be affixed at the pipe to ensure prompt pipe speech.
, or "siphon effect," causing a low pressure
area to be created just below the mouth. When this low pressure area reaches a critical stage, it pulls the airstream past the edge of the mouth, filling the vacuum. This alternately pressurizes the inside and outside of the opening, pressurizing and rarefying the air in the pipe's resonator. The column of air in the resonator thus vibrates at a frequency determined by the pipe's dimensions.
See Wind Instrument
.
term fonds) sound of an organ is composed of varying combinations of these three tonal groups, depending upon the particular organ and the repertory being played.
The end of the pipe opposite the mouth may be either open or closed (also known as "Gedecked" or stopped). A closed pipe
sounds an octave lower than an open pipe
of the same length. Also, an open pipe produces a tone in which both the even-numbered and the odd-numbered partials
are present, while a stopped pipe produces a tone with odd-numbered partials. The tone of a stopped pipe tends to be gentler and sweeter than that of an open pipe, though this is largely at the discretion of the voicer.
, "flutes" are generally the widest flue pipes and produce the tone with the most fundamental among flue pipes. They are so named because they sound like the flute
; though most flute stops are not intended to imitate the orchestral instrument, they produce a similar sound. A stopped flute, such as the (German
for "covered"), produces a more muffled sound, while an open flute, such as the (German for "forest flute"), produces a rounder, open sound. The (French
for "harmonic flute"), whose use the great 19th-century French organ builder Aristide Cavaillé-Coll
advocated, is a metal flute pipe of double length with a hole punched in the center, which causes the pipe to speak at its first partial with a very round, intense sound. Cavaille-Coll used the names and for the 4-foot and 2-foot harmonic flutes, respectively. The (German for "pipe flute", or more commonly "chimney flute" in English) is a stopped flute rank with a small pipe or chimney built into the cap.
), a range of nine octaves.
A stop of diapason type may or may not actually be labelled "Diapason." The "Diapason" label is most commonly used in English-style organs, whereas the same type of stop is known as a "Prinzipal" or "Principal" on German-style organs and for French language organs they would typically be called "Montre" (literally on "Display" - i.e. the pipes at the front of the organ case) or "Prestant" ("standing in front" Latin 'praestare'). Furthermore, diapasons at pitches higher than 8′ pitch are often labelled with other names. For example, on English-style organs, the stops called Principal and Fifteenth sound one octave and two octave pitches respectively above the 8′ Diapason; on German-style organs, the name Octav is used to indicate the stop an octave above the 8′ Prinzipal, and similarly for French instruments, the names Octave and Doublette for 4′ and 2′ pitches respectively are commonly used.
In Italian organs, the 8' and sometime the 16' pitches are called "Principale" and form the foundation of the entire organ. One characteristic of the classic Italian organ (starting from the 16th century on) is the separated "Ripieno". The "Ripieno" includes many Diapason stops, all separate, on the contrary of the German and French style "Fourniture" and "Mixtur". The 4' pitch is called "Ottava" and all the others are named after the harmonic they produce. They can go up to the "Quadragesima Terza" (43rd), a pipe of 1/8' pitch.
string instruments such as the Violoncelle
, the Gamba
, the Geigen (from the German geige, for violin
), and the Viol
.
). Examples include the Voix céleste (French for celestial voice), typically tuned slightly sharp, and the Unda maris (Latin
for sea waves), typically tuned slightly flat. String stops are most commonly used as undulating stops, though some builders have made undulating flute stops (notably Ernest M. Skinner
's Flute celeste), and rarely an organ may feature an undulating diapason, as in the Italian "Voce Umana" (not to be confused with the Vox Humana
, which is a soft reed stop with a short resonator).
of the pipe: i.e., wide-scaled, normal-scaled, or narrow-scaled. As a pipe's scale increases, more fundamental will be present, and fewer partials will be present in the tone. Thus, the tone becomes richer and fuller as the pipe's diameter widens from string scale to principal scale to flute scale.
The material out of which the pipe is constructed also has much to do with the pipe's final sound. While recent scientific studies have shown that the nature of the metal used in making the pipe has little or no effect on the final sound, organ builders agree that a tin/lead alloy, for example, creates a very different tone than does zinc or copper metals or spotted or frosted alloys.
Organ pipe
An organ pipe is a sound-producing element of the pipe organ that resonates at a specific pitch when pressurized air is driven through it. Each pipe is tuned to a specific note of the musical scale...
that produces sound through the vibration of air molecules, in the same manner as a recorder
Recorder
The recorder is a woodwind musical instrument of the family known as fipple flutes or internal duct flutes—whistle-like instruments which include the tin whistle. The recorder is end-blown and the mouth of the instrument is constricted by a wooden plug, known as a block or fipple...
or a whistle
Whistle
A whistle or call is a simple aerophone, an instrument which produces sound from a stream of forced air. It may be mouth-operated, or powered by air pressure, steam, or other means...
. Air under pressure (referred to as wind) is driven down a flue and against a sharp lip called a Labium, causing the column of air in the pipe to resonate at a frequency determined by the pipe length. See wind instrument
Wind instrument
A wind instrument is a musical instrument that contains some type of resonator , in which a column of air is set into vibration by the player blowing into a mouthpiece set at the end of the resonator. The pitch of the vibration is determined by the length of the tube and by manual modifications of...
. Thus, there are no moving parts in a flue pipe. This is in contrast to reed pipe
Reed pipe
A reed pipe is an organ pipe that is sounded by a vibrating brass strip known as a reed. Air under pressure is directed towards the reed, which vibrates at a specific pitch. This is in contrast to flue pipes, which contain no moving parts and produce sound solely through the vibration of air...
s, which are driven by a beating reed, as in a clarinet
Clarinet
The clarinet is a musical instrument of woodwind type. The name derives from adding the suffix -et to the Italian word clarino , as the first clarinets had a strident tone similar to that of a trumpet. The instrument has an approximately cylindrical bore, and uses a single reed...
. Flue pipes are common components of pipe organ
Pipe organ
The pipe organ is a musical instrument that produces sound by driving pressurized air through pipes selected via a keyboard. Because each organ pipe produces a single pitch, the pipes are provided in sets called ranks, each of which has a common timbre and volume throughout the keyboard compass...
s.
Stop
Flue pipes include all stops of the "Principal", "Flute", and "String" classes, and some stops from the "Hybrid" class.Construction
Flue pipes may be metallic or wooden. Metal pipes are usually circular in cross section; wooden pipes, square or rectangular, though triangular and round wooden pipes do exist.A flue pipe has two major parts, a foot and a resonator. The foot is the bottom portion of the pipe, usually conical. At its base is the toe hole, through which wind enters it. The length of the foot does not affect the pipe's pitch, so organ builders vary the foot lengths of their flue pipes depending on other factors, including the desired shape of the pipes in the façade, the height of the rackboard in which the pipes are seated, and the weight of the completed pipe.
The resonator supports the oscillations of air generated at the mouth of the pipe, a horizontal opening at the juncture of the resonator with the foot. The voicing, the length of the resonator, and the resonator's volume all determine the fundamental pitch of the flue pipe. The conical taper of the pipe determines the overblown pitch. If the pipe is metal, a tuning sleeve or tuning collar may be fixed at the top of the resonator and raised or lowered to vary its length, thereby adjusting the pitch produced.
Between the foot and the resonator, the side of the pipe containing the mouth is flat. A plate of metal or wood called a languid, fixed horizontally here, blocks the airway, except for a small slot called the windway alongside the mouth. This allows air to flow as a sheet of wind directed towards the pipe's mouth. Flat pieces of metal or wood called ears may be attached to the sides of the mouth for tuning purposes, and a horizontal dowel called a roller or beard may be affixed at the pipe to ensure prompt pipe speech.
Actuation
When wind is driven into the foot of the pipe, a sheet of wind is focused by the windway across the mouth to strike just above the edge of the upper lip. This creates a Bernoulli effectBernoulli's principle
In fluid dynamics, Bernoulli's principle states that for an inviscid flow, an increase in the speed of the fluid occurs simultaneously with a decrease in pressure or a decrease in the fluid's potential energy...
, or "siphon effect," causing a low pressure
Pressure
Pressure is the force per unit area applied in a direction perpendicular to the surface of an object. Gauge pressure is the pressure relative to the local atmospheric or ambient pressure.- Definition :...
area to be created just below the mouth. When this low pressure area reaches a critical stage, it pulls the airstream past the edge of the mouth, filling the vacuum. This alternately pressurizes the inside and outside of the opening, pressurizing and rarefying the air in the pipe's resonator. The column of air in the resonator thus vibrates at a frequency determined by the pipe's dimensions.
See Wind Instrument
Wind instrument
A wind instrument is a musical instrument that contains some type of resonator , in which a column of air is set into vibration by the player blowing into a mouthpiece set at the end of the resonator. The pitch of the vibration is determined by the length of the tube and by manual modifications of...
.
Tonal groups
Flue pipes generally belong to one of three tonal families: flutes, diapasons (or principals), and strings. The basic "foundation" (from the FrenchFrench language
French is a Romance language spoken as a first language in France, the Romandy region in Switzerland, Wallonia and Brussels in Belgium, Monaco, the regions of Quebec and Acadia in Canada, and by various communities elsewhere. Second-language speakers of French are distributed throughout many parts...
term fonds) sound of an organ is composed of varying combinations of these three tonal groups, depending upon the particular organ and the repertory being played.
The end of the pipe opposite the mouth may be either open or closed (also known as "Gedecked" or stopped). A closed pipe
Closed tube
In the field of acoustics, a tone is created by the periodic vibrations of air applied to a resonator. There are several ways in music to create such vibrations. One of these is to use a closed tube and to blow across the end. This creates a Bernoulli, or "siphon", effect just below the open end or...
sounds an octave lower than an open pipe
Open tube
In the field of acoustics, a tone is created by the periodic vibrations of air. There are several ways in music to create such vibrations. One of these is to use a tube and to blow across the end. This creates a note of a given frequency, depending on the length of the tube and the pressure of the...
of the same length. Also, an open pipe produces a tone in which both the even-numbered and the odd-numbered partials
Harmonic series (music)
Pitched musical instruments are often based on an approximate harmonic oscillator such as a string or a column of air, which oscillates at numerous frequencies simultaneously. At these resonant frequencies, waves travel in both directions along the string or air column, reinforcing and canceling...
are present, while a stopped pipe produces a tone with odd-numbered partials. The tone of a stopped pipe tends to be gentler and sweeter than that of an open pipe, though this is largely at the discretion of the voicer.
Flutes
In the system of organ flue pipe scalingOrgan flue pipe scaling
The subject of this article is technical in nature and requires an understanding of organ terminology. This is in the process of being rectified. Many of the terms used here are defined in the pipe organ article....
, "flutes" are generally the widest flue pipes and produce the tone with the most fundamental among flue pipes. They are so named because they sound like the flute
Flute
The flute is a musical instrument of the woodwind family. Unlike woodwind instruments with reeds, a flute is an aerophone or reedless wind instrument that produces its sound from the flow of air across an opening...
; though most flute stops are not intended to imitate the orchestral instrument, they produce a similar sound. A stopped flute, such as the (German
German language
German is a West Germanic language, related to and classified alongside English and Dutch. With an estimated 90 – 98 million native speakers, German is one of the world's major languages and is the most widely-spoken first language in the European Union....
for "covered"), produces a more muffled sound, while an open flute, such as the (German for "forest flute"), produces a rounder, open sound. The (French
French language
French is a Romance language spoken as a first language in France, the Romandy region in Switzerland, Wallonia and Brussels in Belgium, Monaco, the regions of Quebec and Acadia in Canada, and by various communities elsewhere. Second-language speakers of French are distributed throughout many parts...
for "harmonic flute"), whose use the great 19th-century French organ builder Aristide Cavaillé-Coll
Aristide Cavaillé-Coll
Aristide Cavaillé-Coll was a French organ builder. He is considered by many to be the greatest organ builder of the 19th century because he combined both science and art to make his instruments...
advocated, is a metal flute pipe of double length with a hole punched in the center, which causes the pipe to speak at its first partial with a very round, intense sound. Cavaille-Coll used the names and for the 4-foot and 2-foot harmonic flutes, respectively. The (German for "pipe flute", or more commonly "chimney flute" in English) is a stopped flute rank with a small pipe or chimney built into the cap.
Diapasons
Diapasons or principals represent the characteristic sound of the pipe organ. They are not intended to imitate any other instrument or sound. They are medium-scaled and are often prominently featured in the façades of pipe organs, often painted and decorated. Diapasons appear throughout the entire range of the instrument, from 32′ pitch to 1′ pitch (not including mixturesMixture (music)
A mixture is an organ stop, usually of principal tone quality, that contains multiple ranks of pipes. It is designed to be drawn with a combination of stops that forms a complete chorus . The mixture sounds the upper harmonics of each note of the keyboard...
), a range of nine octaves.
A stop of diapason type may or may not actually be labelled "Diapason." The "Diapason" label is most commonly used in English-style organs, whereas the same type of stop is known as a "Prinzipal" or "Principal" on German-style organs and for French language organs they would typically be called "Montre" (literally on "Display" - i.e. the pipes at the front of the organ case) or "Prestant" ("standing in front" Latin 'praestare'). Furthermore, diapasons at pitches higher than 8′ pitch are often labelled with other names. For example, on English-style organs, the stops called Principal and Fifteenth sound one octave and two octave pitches respectively above the 8′ Diapason; on German-style organs, the name Octav is used to indicate the stop an octave above the 8′ Prinzipal, and similarly for French instruments, the names Octave and Doublette for 4′ and 2′ pitches respectively are commonly used.
In Italian organs, the 8' and sometime the 16' pitches are called "Principale" and form the foundation of the entire organ. One characteristic of the classic Italian organ (starting from the 16th century on) is the separated "Ripieno". The "Ripieno" includes many Diapason stops, all separate, on the contrary of the German and French style "Fourniture" and "Mixtur". The 4' pitch is called "Ottava" and all the others are named after the harmonic they produce. They can go up to the "Quadragesima Terza" (43rd), a pipe of 1/8' pitch.
Strings
String pipes are the smallest-scaled flue pipes. This produces a bright sound that is rich in upper partials. String stops are generally named after bowedBow (music)
In music, a bow is moved across some part of a musical instrument, causing vibration which the instrument emits as sound. The vast majority of bows are used with string instruments, although some bows are used with musical saws and other bowed idiophones....
string instruments such as the Violoncelle
Cello
The cello is a bowed string instrument with four strings tuned in perfect fifths. It is a member of the violin family of musical instruments, which also includes the violin, viola, and double bass. Old forms of the instrument in the Baroque era are baryton and viol .A person who plays a cello is...
, the Gamba
Gamba
Gamba is a small town in Gabon lying on the southern bay of the Ndogo Lagoon. Historically, the area was populated by gatherer-hunter-fishermen autochthons scattered in small villages around the Ndogo Lagoon and the Yenzi Lake....
, the Geigen (from the German geige, for violin
Violin
The violin is a string instrument, usually with four strings tuned in perfect fifths. It is the smallest, highest-pitched member of the violin family of string instruments, which includes the viola and cello....
), and the Viol
Viol
The viol is any one of a family of bowed, fretted and stringed musical instruments developed in the mid-late 15th century and used primarily in the Renaissance and Baroque periods. The family is related to and descends primarily from the Renaissance vihuela, a plucked instrument that preceded the...
.
Undulating stops
Often, an organ will feature two similarly-voiced stops, one tuned slightly sharp or flat of the other. When these stops are played together, a unique undulating effect results due to alternating constructive and destructive interference (beat frequencyBeat (acoustics)
In acoustics, a beat is an interference between two sounds of slightly different frequencies, perceived as periodic variations in volume whose rate is the difference between the two frequencies....
). Examples include the Voix céleste (French for celestial voice), typically tuned slightly sharp, and the Unda maris (Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...
for sea waves), typically tuned slightly flat. String stops are most commonly used as undulating stops, though some builders have made undulating flute stops (notably Ernest M. Skinner
Ernest M. Skinner
Ernest M. Skinner was one of the most successful American organ builders of the early 20th century.-Early years:...
's Flute celeste), and rarely an organ may feature an undulating diapason, as in the Italian "Voce Umana" (not to be confused with the Vox Humana
Vox humana
The Vox Humana is a short-resonator reed stop on the pipe organ, so named because of its supposed resemblance to the human voice. As a rule, the stop is used with a tremulant, which undulates the wind supply, causing a vibrato effect...
, which is a soft reed stop with a short resonator).
Labial reeds
Some flue pipes are designed to produce the sounds of reed pipes or to imitate the sounds of orchestral instruments which are approximated by reed pipes. The sound is generally more mellow and sweet than that of a true reed pipe. Examples include the Saxophone, the Muted horn, the Clarinet flute, and the Echo oboe.Tonal characteristics
The diameter of a flue pipe directly affects its tone. When comparing pipes of otherwise identical shape and size, a wide pipe will tend to produce a flute tone, a medium pipe a diapason tone, and a narrow pipe a string tone. These relationships are referred to as the scaleOrgan flue pipe scaling
The subject of this article is technical in nature and requires an understanding of organ terminology. This is in the process of being rectified. Many of the terms used here are defined in the pipe organ article....
of the pipe: i.e., wide-scaled, normal-scaled, or narrow-scaled. As a pipe's scale increases, more fundamental will be present, and fewer partials will be present in the tone. Thus, the tone becomes richer and fuller as the pipe's diameter widens from string scale to principal scale to flute scale.
The material out of which the pipe is constructed also has much to do with the pipe's final sound. While recent scientific studies have shown that the nature of the metal used in making the pipe has little or no effect on the final sound, organ builders agree that a tin/lead alloy, for example, creates a very different tone than does zinc or copper metals or spotted or frosted alloys.