Audioscan Verifit 2 - Manual (Page 37)

Verifit ® User's Guide Version 4.2 © June 2015
of the client’s head. This speaker will be automatically used for the on-ear directional test.
On-ear calibration facts
The probe microphone and its associated tubing does not have a flat frequency response. The on-ear calibration
process compares this response with the flat, factory-calibrated response of the on-ear reference microphone and
compensates all subsequent probe-tube measurements for this difference. It may be performed as often as
desired but will be invalidated at 12 am the following day or at 12 am the following Monday, depending on the
choice of daily or weekly calibration interval. After the calibration has expired, you will be prompted to
calibrate whenever you attempt a test that uses the on-ear measurement microphones.
It is suggested that a copy of the calibration curves for the probe modules when new be posted near the Verifit
for comparison with daily or weekly curves. If there is a drift in calibration with time, the module may need
replacement. See Calibration check for probe module.
Calibration should be repeated if a probe module is replaced or if a probe-tube with different dimensions is
installed.
Switching left and right probe modules after calibration will result in the wrong calibration curve being applied.
Calibration of on-ear probe microphone
For convenience, the probe microphones can be calibrated while seated in the probe dock. Ensure the connectors
of both probe microphone assemblies are plugged into the appropriate jack on the bottom of the probe dock. See
Microphone connection and On-ear calibration facts
1. Right-click to raise the home menu and click on [Calibration] under [On-ear measures].
2. Press the enlarged end of a probe tube as far as it will go, into the recessed opening at the top of the probe
module.
3. Position the open end of the probe tube in front of the reference microphone inlet and press it between the
posts as shown.
4. Hold the probe dock 15 - 90 cm (6 – 36 in.) away from and directly in front of the sound-field loudspeaker
with the microphone to be calibrated facing the speaker.
5. Left-click calibrate. The resulting curve should be similar in shape to that shown but may be shifted +/- 5 dB.
6. To change the calibration interval, toggle [Daily] or [Weekly].
Click on calibrate for the other ear and repeat the process for the other probe module.
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