WARBLE-TONE AUDIOMETER

Typical Number in Hospital: 1

Cost Bands: 3

References:

Audiology and hearing aid departments often use free-field tests (as opposed to using headphones) for diagnostic and hearing aid fitting purposes. Free-field tests should ideally be conducted in an acoustic booth or audiometric room having a low reverberation time and walls with a high sound-absorbing quality, so that the space appears to be a free field. In all but the highest quality audiometric room, there is a problem with standing waves when using single-frequency test tones. This occurs when the distance between any two surfaces in the room is a multiple of the wavelength of the test tone and results in areas of high and low-intensity sound, reducing the potential accuracy of the method. One way of reducing this problem is to use a warble-tone audiometer which produces test tones with rapidly fluctuating frequency (warble tones) instead of pure tones. A warble-tone generator is often an accessory for a pure- tone audiometer.