Laryngophone

laryngophone [lə′riŋ·gə‚fōn]

(engineering acoustics)

A microphone designed to be placed against the throat of a speaker, to pick up voice vibrations directly without responding to background noise.

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Laryngophone 

a converter of the mechanical oscillations (vibrations) of the cords and cartilage of the larynx into electrical oscillations, minimally sensitive to oscillations of the environment.

The laryngophone is used in communications devices when the speaker is surrounded by a very high noise level (some industrial and construction sites, airplanes, tanks) but where the use of conventional microphones is inadvisable. The design elements of the laryngophone are arranged in a small, plastic, round or oval case (diameter, 12–35 mm; height, 10–20 mm). One side of the casing or base of the portable laryngophone system should fit tightly against the throat, whose vibration will activate its transforming element (contact with carbon powder, piezo elements, armature of an electromagnet). There are often two laryngophones, one placed on each side of the larynx. Together with telephones, laryngophones make up a head and chest set often mounted in a helmet.

Depending on the principle by which the mechanical oscillations are converted into electricity, a distinction is made between carbon, piezoelectric, and electromagnetic laryngophones. In terms of their electroacoustic parameters, laryngophones are somewhat inferior to the corresponding types of microphones. However, they can provide adequate transmission intelligibility.

A. G. DOL’NIK