Hierarchy classification:

1. top of the aat hierarchies
2. Objects Facet
3. Visual and Verbal Communication (hierarchy name)
4. Information Forms (hierarchy name)
5. information forms (objects)
6. information artifacts
7. [information artifacts by physical form]
8. recordings
9. sound recordings

Anotations

Scope note:

Visual records or representations of sound created using Fourier analysis, particularly speech, with colors or densities corresponding to time, frequency, and energy comprised in the sound. Created by a sound spectrograph. Sound specrography was developed at Bell Laboratories in the 1940s.