– Int.File (integrated OTOsuite Speech Material or regular sound files)
– Line In (analog input from external sound players, eg. CD, MD, MP3 or cassette recorders connected to the audi-
ometer via the Line In input).
Important • If an external playback device is used to generate speech stimuli via the line input, care must be
taken to ensure that the player has a flat frequency response in the range 125 to 6300 Hz. The maximum allow-
able deviation from the average response level is +/-1 dB; the average response level should be measured over the
range 250 to 4000 Hz.
Both the headset microphone and the desktop microphone are ready for use and do not require calibration or
equalization procedures. The headset microphone should be turned to a position just below the operator’s
mouth. The desktop microphone should face the operator.
If an external playback device is used to generate speech stimuli via the line input of AURICAL Aud, only a high
quality CD player or similar device should be used; tape recordings may not provide a sufficient signal to noise
ratio. Preferably, the external device should deliver its output via a fixed-level line out connector. The input gain
on AURICAL Aud should be adjusted to obtain a 0 dBVU reading when the calibration signal is played by the
external device.
8. You can find speech material files in the File/track/list selection drop-down list.
Caution • You should only use speech materials with a stated relationship between the level of the speech signal
and the calibration signal.
Speech materials delivered on CD or other media are normally accompanied by a description of this relationship.
You should follow the instructions supplied with the speech materials, using the VU-meter in OTOsuite for adjust-
ment of input gain.
If you are using built-in speech materials supplied with OTOsuite, the speech levels have been adjusted according
to the original speech material instructions.
Note • Speech signals are calibrated in dB HL.
18 Otometrics - AURICAL Aud
14 Performing speech audiometry
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