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:

Instruments that give visual representation of sounds, consisting of tubes closed at one end by a taught membrane with a small mirror attached to its centre, which vibrates in response to sound entering the tube at the open end, causing a spot of light reflected by the mirror on to a screen to vibrate with varying amplitude and frequency.