The queen of musical instruments

The history of the pipe organ

The earliest the

hydraulus known wind instrument not blown by the human lungs is believed to belong to

Ctesibius of Alexandria (fl. 285–222 B.C.) [146, pp. 1–2]. This instrument was composed of a water tank and a trumpet attached to it, with the mouthpiece connected to an open hole on the

5

top of the tank. To produce sound, air was conveyed into the trumpet by pumping more water into the tank, which forced the remaining air out of the tank through the hole at the top. This idea was extended by Hero—a student of Ctesibius—who attached a row of pipes to the water tank arranged in a musical scale. This instrument is called thehydraulus(hydraulic organ) and it became widespread in antique Greece and the Roman Empire.

While organum

pneu-maticum

the hydraulus enjoyed great popularity, a similar instrument called organum pneu-maticum(pneumatic organ) appeared around the second century [150, p. 35]. In this instrument, which presumably originated from thebagpipe, unlike the hydraulus, the pressure needed for air to flow into the pipes was not provided by water, but air. At that times, the organum pneu-maticum referred to a smaller instrument compared to the hydraulus with less pipes and smaller sound power, used mainly for entertainment in the Roman era. However, by the eighth century, becoming larger and gaining more sound power, the pneumatic organ had assumed its promi-nent place in the liturgy of the catholic church, as initiated by Pope Vitalian [146, pp. 26–29].

In the medieval era medieval

organs

the size of pneumatic organs started to grow rapidly. As an extraordinary example, the organ in the cathedral of Winchester (built around980A.D.), had more than400 pipes,26blower machines, which required70people to operate them [150, p. 52]. At this time one key on the keyboard could sound more than ten pipes at the same time. The increased size also introduced new problems and required technical improvements to solve them. One of the greatest inventions is the mechanical transmission, the so-calledrollerboard(Wellenbrett), which was introduced in the 14^thcentury and enabled the reduction of the size of the keyboard.

The pipe organ modern

pipe organs

has undergone a lot of innovations and technical improvements while pre-serving its main principle of functioning from the 15^th century. Along with the clock, the pipe organ was considered one of the most complex human-made mechanical creations before the Industrial Revolution. Due to its wide tonal range, its ability of imitating the sound of various in-struments, and its grandiose size, the pipe organ is often called the “queen of musical instruments”, after W. A. Mozart.

Parts of the pipe organ

The schematic of a modern pipe organ is depicted in Figure 2.1. The picture only illustrates the most important parts of the instrument and their connections while omitting several details.

In modern pipe organs theventilation system ventilation

system

—or wind system (Windwerk)—consists of four essential parts. Theblower(Gebläse), which is often an electrical fan nowadays, is the air supply of the instrument. It pumps air into the ventilation system, according to the “wind consumption”

of the instrument. Theroller valve(Rollenventil) regulates the air flow from the blower into the bellows. Thebellows(Balg) ensure that the pressure in the windchest remains constant. By plac-ing different weights on the top of the bellows the pressure can be controlled. Finally, thewind duct(Windkanal) connects the ventilation system with thewindchest, providing the air supply for the pipes. In large organs, more ventilation systems can be present and operate at the same time.

Thewindchest(Windlade) is one of the most important parts of the pipe organ that connects the wind system, the keyboards and the pipes. The pipes

voices, ranks, stops

are connected to the windchest, ar-ranged intoranks(Pfeifenreihe) andstops(Register). Each stop covers a certain range of musical tones. Special stops, such as mixtures(Mixtur) can consist of multiple ranks, activated by the same keys and hence multiplevoices(Stimme) can sound at the same time.

There are various kinds of windchest the

windchest

constuctions, such as the slider chest, the spring chest, the cone valve chest, and the Pitman chest, see [57, ch. 7] for further details. In the traditional windchest—the so-calledslider chest(Schleiflade), which is also shown in Figure 2.1—the pipes corresponding to the same musical note from all stops are connected to onekey channel (Tonkan-zelle). The key channels are separated by valves from thepallet box(Windkasten), which is the lowest part of the windchest. The pipes are separated from the key channels by theslides (Schlei-fe), which are controlled by thedrawstops(Registerzug). The slider is a wooden plate that has a

2.1. THE PIPE ORGAN AND ORGAN PIPES 7

Blower Roller valve Bellows Wind duct

| {z }

Wind system Regulator z }| { Keyboards

(and pedals)

Drawstops Windchest (Slider chest)

Slides

Key channels Pallet box

Pipe ranks (Stops)

Rollerboard

Figure 2.1.The schematic of a modern pipe organ and its most important parts

number of holes in it, corresponding to the position of the pipes. By activating a stop, the holes of the slider plate let the air flow from the key channel into the pipes. Thus, by means of the keys (or pedals) and the drawstops the pipes to be sounded are selected like selecting certain rows and columns of a matrix.

The keyboards and pedals keyboards

and pedals

control the valves inside the pallet box and hence the flow of air into the key channels. In organ building, it is usual to express the pitch of the note infeet (Fuß-lage). Usually, the keyboards cover five octaves with 61 keys from the 8’ C to¹/4’ C, while the pedals cover the range of 2¹/2octaves from 8’ C to 1¹/2’ F. By drawing different stops, the pitch corresponding to one key or pedal can be changed (e.g. by choosing a 16’ stop, the first key will sound a 16’ C note), and thus the musical range of the keyboard can be extended. The keyboards and pedals are traditionally connected to the windchest by a mechanical transmission, called the rollerboard(Wellenbrett); however, remote electronical controllers also exist.

All organ pipes produce sound by means of air flowing into the pipe. When a key on the keyboard is pressed the corresponding valve in the pallet opens, which lets air flow into the key channels and the pipes selected by the drawstops. When the key is released a spring closes the valve and the way of the airflow is blocked. Unlike the keys of the piano, for example, the sound power is not controlled directly by the strength of the strike on the keyboard.¹Thus, the loudness of a tone or chord can be controlled by special devices, such as theswell(Schwellwerk); however, the resulting sound power mainly depends on the configuration of the individual pipes. In a usual setup, about the 85–90% of the pipes are labial(Labialpfeife), while the rest arelingual pipes (Zungenpfeife). In some modern pipe organs, a third type of pipes, the so calleddiaphone pipes are also present. These pipes have some characteristics in common both with labial and lingual organ pipes and are mainly used in bass (16’ or 32’) stops. In the next sections, labial and lingual pipes are discussed separately. Diaphone pipes are not addressed in the following parts of the thesis.