Hierarchy classification:

1. top of the aat hierarchies
2. Objects Facet
3. Furnishings and Equipment (hierarchy name)
4. Sound Devices (hierarchy name)
5. sound devices (equipment)

Anotations

Scope note:

Devices comprised of acoustic receivers positioned at right angles to one another and attached to a shaft that is held by the user. The sound collected by these horns is conducted to ear-pieces through rubber hoses. Developed to discover the position of the source of sounds in space, as invented ca.1880, particularly for use on ships to locate the position of foghorns.