Pure tones are used for audiometry because they are frequency-specific

Evidence

The pure tone is one of the most basic forms of sound and, importantly, is the foundation of a typical audiometric assessment in the form of the audiogram, a report of the ability to detect pure tones as a function of frequency. Pure tones are preferred for audiometric testing over other sounds (such as noises or modulated sounds) as they contain a single frequency and therefore are the most frequency-specific sounds. — Jennifer Lentz, Psychoacoustics- Perception of Normal…, 161

Categorization

• DEFINE: Defines both the pure tone and the audiogram while explaining why this particular stimulus was chosen for clinical testing.