Audioscan Verifit 2 Manuel d'utilisateur télécharger pdf (Page 39)

Verifit

User's Guide Version 4.2 © June 2015

Calibration check for probe module

The calibration curve for the probe module is a comparison of the response of the probe microphone (with tube)

to the response of the on-ear reference microphone. Any change in the curve indicates a change in one of these

microphones (or the probe tube). See Calibration of on-ear probe microphone. As part of a regular calibration

schedule, or to investigate changing calibration curves, the on-ear reference microphone may be checked against

a high quality sound level meter.

1. Right-click to raise the home menu and click [Manual control] under On-ear.

2. Click [Level], then select 70 from the drop-down list.

3. Click [Frequency], then select 2000 Hz from the drop-down list.

4. Click [Start test] (which changes to [Stop test]).

5. Hold the probe module about 45cm (18 in.) in front of the sound-field speaker.

6. Hold the microphone of a calibrated sound level meter next to the on-ear reference microphone as shown.

Set the sound level meter to C weighting and slow.

7. The sound level meter should read 70 ±2 dB.

8. Repeat with the frequency at 250 Hz.

9. To stop the measurement, left-click [Stop test].

The probe module should be replaced if it fails this test.

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Audioscan Verifit 2 Manuel d'utilisateur Page 39