Sound field audiometry: recommended stimuli and procedures

Area of Science:

• Audiology
• Acoustics
• Hearing Science

Background:

• Sound field audiometry is crucial for assessing hearing thresholds in specific listening conditions.
• Standardized protocols are needed to ensure the reliability and validity of sound field measurements.
• Previous methods lacked comprehensive guidelines for stimulus selection and calibration.

Purpose of the Study:

• To present detailed recommendations for conducting sound field audiometry.
• To establish best practices for stimulus selection, room acoustics, and calibration.
• To ensure the reliability of sound field testing matches that of earphone audiometry.

Main Methods:

• Utilized frequency modulation tones and narrow bands of noise as preferred stimuli.
• Defined optimal stimulus bandwidths varying with center frequency (e.g., 30% at 0.25 kHz to 10% at 4 kHz).
• Recommended non-reverberant test rooms, adjustable seating, and specific calibration methods (control microphone preferred).

Main Results:

• Established specific stimulus characteristics (FM tones, narrow noise bands) and bandwidths for effective sound field testing.
• Provided a calibration method using sound level meter readings (RMS-FAST) and a conversion table for thresholds (dB HTL).
• Demonstrated that the proposed methods achieve reliability equivalent to earphone audiometry.

Conclusions:

• The presented recommendations offer a standardized and reliable approach to sound field audiometry.
• These guidelines facilitate accurate hearing threshold measurements in a sound field environment.
• The findings support the use of sound field testing as a reliable alternative to earphone audiometry.