Audiometric Zero
The standardised reference sound pressure level representing the average threshold of hearing in a young, otologically normal population, against which hearing levels are measured in dB HL.
Full Definition
Audiometric zero defines the 0 dB Hearing Level (HL) reference point on an audiogram, calibrated to the average detection threshold of a population of young adults with normal hearing as specified by ISO 8253 and ANSI S3.6 standards. It differs from acoustic zero (0 dB SPL — Sound Pressure Level) and is frequency-specific, meaning that the physical sound pressure corresponding to 0 dB HL varies across test frequencies. Editors reviewing audiological research or technical documentation must understand that dB HL values are always stated relative to audiometric zero and should not be equated with dB SPL. The concept underpins the scaling of all standard audiograms and is fundamental to interpreting reported hearing thresholds.
Usage
Usage note: Do not equate audiometric zero with 0 dB SPL. Always note the relevant ISO or ANSI standard when accuracy is critical in research publications.
In Context
- "All thresholds are expressed relative to audiometric zero as defined in ISO 8253-1." — Audiological research paper methods section
- "Editors should note that audiometric zero is frequency-dependent and must not be equated with 0 dB SPL." — Technical standards editorial note