Free-field audiometry, also known as sound-field audiometry, is a hearing testing method used to assess an individual's hearing sensitivity in a sound field without the use of headphones or insert earphones. In free-field audiometry, the sound is presented through loudspeakers, and the individual being tested is in an open listening area.
Setup and Procedure:
Sound Booth or Room: Free-field audiometry is conducted in a sound booth or a sound-treated room to control the ambient noise and prevent sound reflections.
Loudspeakers: Several calibrated loudspeakers are placed around the room at specific locations. These speakers emit pure tones (single-frequency sounds) or speech stimuli at predetermined volume levels.
Audiometer: An audiometer is used to generate the pure tones or speech signals and control the intensity (volume) of the sounds presented through the loudspeakers.
Response Mechanism: The individual being tested responds when they hear the sound by raising their hand, pressing a button, or giving a verbal response.
The individual being tested is seated in the sound booth or room at a specified listening position.
Pure tones of varying frequencies and intensities or speech stimuli are presented through the loudspeakers.
The individual responds to the sounds they hear, and the audiologist or hearing care professional records the responses.
Based on the individual's responses, the audiologist plots the results on an audiogram, which is a graphical representation of the individual's hearing thresholds at different frequencies.
Advantages and Uses:
Free-field audiometry is particularly useful for testing young children or individuals with cognitive or physical impairments who may not be able to use conventional headphones or insert earphones.
It allows for a more natural and less intrusive way to assess hearing sensitivity in certain populations.
Free-field audiometry is also commonly used in pediatric audiology settings, where engagement and cooperation may be enhanced through the use of sound-field speakers and toys or visual reinforcement.
However, it's important to note that free-field audiometry may have limitations in accuracy compared to conventional audiometry with headphones or insert earphones. For most adults and older children, conventional audiometry remains the preferred method for obtaining precise and standardized hearing threshold measurements.