Audiometry begins at 1 kHz because it is the most universally audible frequency

Evidence

The usual audiometric procedure for air or bone-conduction measurements (recalling the one difference for bone conduction that the frequencies used are from 500 Hz to 4 kHz only) is to test frequencies (in the following order: 1 kHz, 2 kHz, 4 kHz, 8 kHz, 500 Hz, 250 Hz, 125 Hz, 1 kHz). … (Note that the starting frequency is 1 kHz, which is a mid frequency in the hearing range and is therefore likely to be heard by all subjects to give them confidence at the start and end of a test.) — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 2352

Categorization

• CANDY: Cheap conversational fact: hearing tests start at 1 kHz not out of acoustic interest but to reassure the patient.