The pipe organ is one of the largest and most versatile intruments in the world, combining up to nine octaves through pipes of various sizes, types, and materials. Each pipe produces a unique sound based on the various characteristics of its design.
This article will explore the different types of organ pipes, including different materials for making them, the purpose behind differing sizes, and the reasons behind various styles of pipes.
The Basics of Organ Pipes:
Organ pipes are cylindrical constructions through which air is passed through to produce a musical note. The length, diameter and material of the pipe determines the tone and timbre of the notes produced.
A set of pipes comprising a full musical scale is called a rank. Multiple ranks placed together form a stop.
What Are the Two Main Types of Pipes?
The two main types of organ pipes are known as Flue Pipes and Reed Pipes.
Reed pipes work more like a flute or a clarinet. A vibrating reed is used for manipulating air to produce sound.
Reed pipes can come in two different styles of pipes: Solo Reeds and Chorus Reeds
Solo Reeds can be used alone in their own ranks, and usually work well with chorale pieces.
Chorus Reeds are usually louder and are often used to enhance the sounds of other stops.
Flue pipes work the same way as a recorder, by forcing air through a fipple – a channel through which air is directed to produce sound.
Flue pipes have no moving parts involved in their construction.
Unlike Reed Pipes, Flue pipes have three sub-categories of sound: Principal, Flute, and String
What Are The Differences in the Three Types of Flue Pipes?
Principal Flue Pipes:
These are also called diapasons. Principal flue pipes are the most iconic of organ pipes, and often the most visible.
Principals often form the main stop of the organ.
Many performers prefer these pipes for accompanying choral performances.
Flute Flue Pipes:
Flute pipes often have a larger diameter to produce what is considered a warmer tone.
These can have a variety of shapes to produce different sounds. Some of these include the triangular flue pipe and conical pipes.
These are considered necessary pipes for lyrical organ music. They are also said to have something of a ‘playful’ tone.
String Flue Pipes:
String pipes are designed to imitate the tones of string instruments similar to violins.
They are generally the thinnest diameter pipes in the organ.
These produce softer notes, often integral in performing classical movements.
What Are Open and Closed Pipes?
Closed pipes have one end that is closed off. This is also called a ‘stopped’ pipe.
Open pipes are open on both ends of the pipe.
Each one reflects sound waves differently based on the frequency of the air vibrations.
The closed and open nature of the pipes can create different harmonics and variations when a musician plays.
What Are The Different Shapes of Organ Pipes?
Most pipes are upright cylindrical structures, but not always. Flute pipes in particular often come in special shapes to produce unique tones.
Some are specialized, like the triangular flue pipe. Others can be found in multiple instruments.
The most common and iconic form of pipes. These pipes form the core ranks and stops of pipe organs.
The sizes can range from the length and width of a pencil to the largest pipe, which is 64 feet in length.
Conical pipes can be used as supporting tones in the bass, middle, and treble ranges.
Conical pipes are considered excellent instruments for accompaniment.
According to experts, the conical shape removes some of the resonance of the typical cylindrical shape.
Rectangular pipes are not often found.
Sound generally transmits differently in a rectangular pipe than it does in a circular one, producing a different tone.
Without certain proportions, the sound transmits unevenly, causing different, lighter tonal results.
Many rectangular pipes are flue pipes.
How Do Different Diameters Change the Sound?
There are two different ways that the diameter of the pipe can change the sound.
Wider pipes produce more of a flute-like tone.
Mid-range diameter pipes produce what is called a diapason tone.
Thinner diameter pipes produce more of a string-like tone, to imitate instruments like violins and cellos.
According to some, differing widths provide different ranges of harmonics.
Wider diameters are said to produce fewer harmonics, whereas thinner diameters are reported to provide a richer variety of harmonics.
How Do Different Lengths of Organ Pipes Change the Sound?
Wider and longer pipes produce a lowner, deeper sound. These larger pipes form the core of the bass range.
The thinner and shorter pipes produce the higher treble notes.
What Different Materials Can Organ Pipes Be Made Of?
In theory, organ pipes can be made of almost any material, including stone, porcelain, ivory, glass, plastic, bamboo and even paper.
The most common materials for organ pipes are metal and wood, due to the greater resonance of these materials.
What Kind of Metal is Used in Pipe Organs?
Traditionally organ pipes are made of a lead/tin alloy in various percentages. The lead provides increased rigidity, where the tin and other metals provide different tonal qualities.
Some of the more common alloys, according to organ pipe manufacturers, are:
30% tin, 70% lead – common metal
50% tin, 50% lead – spotted metal
75% tin, 25% lead – plain tin
6% antimony, 94% lead – Antimonial lead
Zinc – used most often for the large bass pipes
These alloys also frequently include trace amounts of metals like copper.
In the 11th century copper pipes began to be used for added brilliance to the tonal qualities of the organ.
Since the 1900s, high purity alloys of copper, zinc and aluminum have been used in organ pipes to make larger pipes. They are also used for improving the tonal transitions in other pipes.
Metal pipes are polished, washed, shined or otherwise altered for visual effect.
What Kinds of Woods Are Used to Make Pipe Organs?
Pipe organs can use several different types of wood in their pipes. Thin planes of wood are glued or lacquered together to form the pipes.
Most wooden pipes are rectangular pipes, but not always.
The type of wood used depends on the tonal qualities desired.
According to expert organ pipe creators, soft woods such as pine and fir are used to provide a more mellow tone.
Harder woods such as oak and poplar, are used to produce clarity and stronger harmonics in the bass lines.
What Are the Uses of Other Materials in Pipe Organs?
Materials other than wood and metal have been occasionally used in pipe organs. Plastic, glass, bamboo and other materials are often used in rare pipe organs.
Plastic Pipe Organs:
Plastic is often used in DIY homemade pipe organs. The most common choice of material is plastic PVC pipe.
Plastic pipes have a decent resonance and are easy to cut to the proper height. PVC pipe organs are often closed pipe configurations.
Different widths are easy to find to include for varying resonances.
Plastic PVC pipes are good for making an inexpensive home instrument.
Glass Pipe Organs:
Glass pipe organs are a rarity due to the delicacy of the material. Most glass pipes are primarily decorative.
Glass is known for it’s high, pure tones, as demonstrated with the common glass instruments.
Ivory in Pipe Organs:
Ivory, like glass, is primarily a decorative feature on pipe organs.
One unique case in Germany ivory and wood combined produce the ‘bird cry’ instrument.
Bamboo in Pipe Organs:
The oldest and most prominent bamboo organ exists in the Philippines. Bamboo is naturally hollow and resonant.
It was originally used due to its prominence in the area, and has similar acoustic properties to wood.
Why Use Alternative Materials for Organ Pipes?
Sometimes the alternative materials are chosen for the visual factors. Others are chosen to experiment with new tones and harmonics.
Others are chosen for availability, for use in homemade or locally made instruments.