The “Kempelen” speaking machine

In the context of the simultaneous exhibition “8 Objects, 8 Museums” by the Leibniz research museums, the Deutsches Museum in Munich presents a research project regarding a speaking machine, which is considered the oldest of its kind.

Speaking machine by Deutsches MuseumLeibniz Association

Kempelen speaking machine 

Synthetic speech is an old dream, albeit with an eerie connotation. The Deutsches Museum houses a speaking machine that is considered the oldest of its kind.  It is a precursor of speech programmes such as Siri. Its performance and functions were previously unknown. The machine is now subject to close examination, and a replica plays a crucial role in this process.

Wolfgang von Kempelen, self-portrait by Szépmüvészeti Múzeum, BudapestLeibniz Association

The inventor

Wolfgang von Kempelen (1734-1804), a high-ranking official at the Austrian court, was a pioneer in the field of speech synthesis. At the time, he was one of the numerous “amateurs” who dabbled in natural sciences and mechanics. His best-known invention was the “Chess Turk.” Since 1769, he worked on his speaking machine, which is considered the first such machine capable of generating entire words. In 1783/84 he presented both inventions during a tour across Europe.

Johann Jacob Ebert: News of the famous chess player and the speaking machine by the Imperial-Royal Court Councillor Herrn von Kempelen. by Deutsches MuseumLeibniz Association

Kempelen's "Chess Turk" was an apparatus that pretended to play chess. It consisted of a puppet and a box in which an elaborate mechanism was concealed with which the pieces were moved. Of course, the box contained a human being who was cleverly concealed. Many people worked on solving the mystery, but it took a long time until it was revealed.

Wolfgang von Kempelen: Mechanisms of human speech, including the description of his speaking machine by Deutsches MuseumLeibniz Association

Kempelen was intent on demonstrating the seriousness of his speaking machine and responded with his book “Mechanismus der menschlichen Sprache” (Mechanism of Human Speech and Language). On more than 450 pages, he examined the origin of speech, its sounds and the human speech organs. At the centre is the chapter dealing with the “Speaking Machine,” in which he describes his research and various devices. Finally, he offers a detailed description of his latest attempt, including numerous scale drawings. This was meant to facilitate replication and further development of the machine.

Speaking machine by Deutsches MuseumLeibniz Association

A disembodied voice 

The speaking machine in the Deutsches Museum was built around 1800. A note labels it as the speaking machine by Wolfgang von Kempelen. The various parts of the device replicate the human speech organs. It is not an automaton with pre-programmed words or sentences; it was played like a musical instrument.

The bellows acts as the lungs. It creates an air flow, the so-called “wind.”

The sound-producing part – the windchest – is hard to see in this picture. It is contained inside a box, which serves as protection and hides the windchest from the spectators’ eyes.

Speaking machine, windchest (top view) by Deutsches MuseumLeibniz Association

The term “windchest” is derived from pipe organ construction. Various mechanisms were operated with levers to produce consonants.

Speaking machine, windchest (interior view) by Deutsches MuseumLeibniz Association

In the speaking machine, the air is not distributed to pipes but to the various devices for sound production that are found on and in the windchest.

Detail of the speaking machine: Reed (right) of the windchest by Deutsches MuseumLeibniz Association

The windchest contains a reed made of a thin strip of ivory just 0.4 mm thick, to which a strip of leather is glued. When air streams into the windchest, the reed (comparable to the reed of a clarinet) begins to vibrate, thus producing a sound.

The speaking machine’s windchest by Deutsches MuseumLeibniz Association

Vowels, as well as the nasals “M” and “N”, were produced by opening and closing the funnel, which represents the oral cavity.

The nostrils are represented by two small tubes. They are important for producing the “M” and “N” sounds and are made of rolled-up paper.

Replica of the speaking machine by Deutsches MuseumLeibniz Association

Construction of a replica

In order to understand the speaking machine and its workings without damaging the original, the Deutsches Museum built a replica. The construction was preceded by a detailed documentation of the original, which also included a computer tomography.

Windchest, as represented by computer tomography by Deutsches Museum / Klinik Augustinum MünchenLeibniz Association

The computer tomography formed the basis for understanding the machine and for creating a replica. Transect images represent each level in a distortion-free manner, which can be used to obtain the measurements necessary for building the replica. The images were particularly helpful to gain insights about the inaccessible parts in the speaking machine’s interior.

Replica of the speaking machine, Deutsches Museum, 2013/14 by Deutsches MuseumLeibniz Association

Various scientists and workshops at the museum as well as external experts collaborated in the construction of the replica. In this, traditional craftsmanship techniques were used as well as modern manufacturing methods. In order to allow a view into the exciting interior, the replica, in deviation from the original, is built with transparent walls.

Kempelen speaking machine, replica by Deutsches Museum MünchenLeibniz Association

Aufnahme des Sprechapparats (Replik)

A highlight of the research process was the systematic experimenting with the replica. This provided answers to questions that had been a mystery to science until then: What is the effect of various techniques, e.g., when using the bellows? As with a musical instrument, playing the device involves a learning process – without a teacher. It became apparent that the speaking machine’s functional range is smaller than originally thought. It can say “mama”, “papa”, “oma” and similar basic words (see audio recording).

Speaking machine, box hiding the windchest by Deutsches MuseumLeibniz Association

An original Kempelen?

“Kempelen or not Kempelen?” – that is a frequently raised question. For several years, the machine’s authenticity has been increasingly doubted. Therefore, the Deutsches Museum carefully checked the dating and attribution of the speaking machine. There is no doubt that it is a device of the type described by Kempelen, but did Kempelen actually build it? Or was it a reproduction or a compilation of parts from different periods?

Wolfgang von Kempelen: Mechanism of human speech, including the description of his speaking machine by Deutsches MuseumLeibniz Association

The comparison of the speaking machine with the description given by Kempelen in his book of 1791 was largely consistent.

Speaking machine, windchest (top view) by Deutsches MuseumLeibniz Association

All deviations represent improvements compared to the described device; in part, they even realise suggestions formulated by Kempelen himself.

Note attached to the speaking machine by Deutsches MuseumLeibniz Association

The note was attached to the device at a later time – presumably, it only became necessary once a direct link to Kempelen no longer existed. To determine when the note was attached, the paper, the ink and the writing need to be examined and historical photographs and potential comparison material must be researched.

Speaking machine, detail, mouth funnel, Deutsches Museum, From the collection of: Leibniz Association
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Infrared spectroscopy revealed that the mouth funnel is made of natural rubber. It is cut from a container with a floral embossing. This is in keeping with Kempelen’s statement that the mouth funnel is a “piece from an ordinary bottle made of elastic rubber.”

Bottle made of natural rubber, Deutsches Museum, From the collection of: Leibniz Association
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A historical bottle from the Amazon region, which is part of the Chemistry collection at the Deutsches Museum, was used for comparison: It is also made of natural rubber and bears a floral pattern.

Mechanical reproduction of the lung in Kempelen’s “Mechanism”, 1791 by Deutsches MuseumLeibniz Association

Man and machine 

Kempelen’s speaking machine combines some of the major historical trends of the 18th century. The period of Enlightenment led to a growing interest in exploring nature. The human body was regarded as a machine, and learned techniques such as playing the trumpet and natural skills were imitated by automata. 

Jacques de Vaucanson: Le Mécanisme,, Universitätsbibliothek Erlangen, 1738, From the collection of: Leibniz Association
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The inventor Jacques de Vaucanson (1709-1782) achieved particular fame for his automata, including his tambourine and flute players. His artificial duck not only flapped its wings and paddled its feet but also ate and appeared to digest (with a rubber tube as intestine) and defecate.

Automatic trumpet player, Friedrich Kaufmann, Deutsches Museum, 1810, From the collection of: Leibniz Association
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The melodies of the life-sized trumpet player automaton by Friedrich Kaufmann (1785-1866) are encoded on pinned barrels. Contemporaries were deeply impressed by the virtuosity of its playing and discussed why the machine was able to play notes impossible to achieve by human trumpet players. The excitement was so great that is was suggested to replace human trumpet players with mechanical counterparts. Today, the trumpet player is housed in the Deutsches Museum.

The Deutsche Museum by Deutsches MuseumLeibniz Association

Masterpieces of science and technology

The Deutsches Museum is one of the largest natural science and technology museums in the world. Its collections comprise more than 100,000 objects, and there are more than 50 individual exhibitions in the main building on the museum island – ranging from astronomy to oceanography. The main building is supplemented by three additional branch museums: The Verkehrszentrum (Transportation Museum) showcases surface transport, the Flugwerft (Aviation Museum) in Schleissheim features aviation, and the Deutsches Museum Bonn displays research and technology since 1945. In addition, the archive, the library and the Deutsches Museum Digital portal serve as important research resources.

Benz Patented Motor Car (1886) by Deutsches MuseumLeibniz Association

The more than 100,000 objects in the collections of the Deutsches Museum include a wide variety of different items such a scientific instruments, all kinds of machines, vehicles, airplanes, musical instruments and household gadgets. Highlights include the first gasoline-powered car by Carl Benz, the Magdeburg hemispheres, the motorised aircraft by the Wright brothers, the U-boat U 1 and the first computers. Even today, adding to the collections forms one of the museum’s core tasks, and the collections continue to grow.

Exhibition view „Willkommen im Anthropozän”. by Deutsches MuseumLeibniz Association

The research in the Deutsches Museum is based on specimens in the collection, such as the speaking machine, or is dedicated to preservation-related issues – e.g., how can objects made of plastic be preserved? Other projects go beyond the collections and examine scientific computing in Germany from 1871 to 1960 or environmental history. The latter led to the first exhibition on the Anthropocene.

Credits: Story

“8 Objects, 8 Museums” is a collaboration project between the Leibniz research museums and the Leibniz-Institut für Wissensmedien in Tübingen in the Leibniz Year 2016.

Research project regarding the “Kempelen speaking machine” of the Deutsches Museum in Munich

All documents and photos:
Deutsches Museum, photos Hans-Joachim Becker
Kempelen self-portrait: Szépmüvészeti Múzeum, Budapest
Vaucanson, Mécanisme: University Library Erlangen

Project management: Silke Berdux

Replica: Alexander Steinbeißer, Claus Grünewald, Model building workshop, workshops for sculpture and electronics

Material examination: Dr. Marisa Pamplona Bartsch

Computer tomography: Augustinum Clinic, Munich

Text and object selection: Silke Berdux
Text: Silke Berdux, Stephan Speicher
Translation: Hendrik Herlyn

Credits: All media
The story featured may in some cases have been created by an independent third party and may not always represent the views of the institutions, listed below, who have supplied the content.
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