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First assignment

  The experimental use of listening equipment's of foreign make in the late 1920's did not satisfy the Dutch army. The nature of the complaints has not been found in writing. But one may safely suppose that the complaints were caused by the clumsiness of the equipment affecting transport, installation and accuracy of measurements.
This caused loss of time which additionally was increased by the required cooperation with the other required equipment. Furthermore the acoustic properties were far from ideal due to e.g. mechanically caused noise during use of the equipment.

The study of this complex was the subject of an assignment of the Committee to the Measurements Building. A number of details and the progress of this first order are still known. Therefore the subject will be discussed to some extent to illustrate the working method of the Measurements Building. According to still existing documents a Czechoslvakian equipment of Goerz has been investigated. Because this equipment contained fundamental deficiencies it was decided to construct a new prototype. This development was subsequently compared with three different listening equipments among which a part of the Goerz equipment.

Doppelt Richtungshorer
Doppelt Richtungshörer, manufacturer Askania, Germany
(full size 285 KB)


 Equipment by Goerz
Half of the equipment by
Goerz, Czechoslovakia
(full size 285 KB)

 Equipment by Barbier
Equipment by Barbier, Bénard
and Turenne, France
(full size 214 KB)


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