Speech Audiometer or Speech Mode of a Clinical Audiometer: The instrument used for speech audiometry is the speech audiometer. Although devices designed specifically for speech audiometry were used in the past, this function is now incorporated into general-purpose clinical audiometers.
The characteristics of audiometers, including those used for speech audiometry, are given in the American National Standard Specifications for Audiometers (ANSI S3.6-2010).
Block diagram of the speech mode (channel) of a clinical audiometer:
The speech mode (or the speech channel) of the clinical audiometer includes the following components:
(1) various sources of recorded speech material, such as a tape deck, compact disk (CD) player, and a computer.
(2) a microphone for live-voice testing.
(3) an input selector to choose the desired source of the speech material.
(4) an input level control, which is used with a VU meter to ensure that the speech signals are at the levels necessary for them to be properly calibrated.
(5) an attenuator to control the level of speech being presented to the patient.
(6) an output selector to direct the speech stimuli to the desired output transducer.
(7) output transducers (earphones, loudspeakers, bone vibrator).
These components are illustrated In the picture above.
Two-room test setup for speech audiometry:
Typical two-room test setup for speech audiometry. Two enclosed rooms are needed, including one for the examiner, because speech is often presented using live voice and a microphone. The enclosed room for the audiologist helps to minimize pickup of unwanted environmental sounds by the microphone during such testing.
⇒ Essentials of Audiology – Stanley A. Gelfand, PhD (Book)
⇒ Audiology: The Fundamentals – FRED H. BESS, PhD (Book)