RM500SL
®
User's Guide Version 3.4
June 2011
11 On-Ear Measures - Setup
Section overview
For accurate, repeatable measurements, the Verifit must be properly set up and calibrated,
the client must be properly positioned and the probe tube must be properly positioned in
the ear canal.
Real-Ear Unaided Response (
REUR
): SPL, or band SPL, in the open (unaided) ear canal for
a given stimulus.
Real-Ear Unaided Gain (
REUG
): Difference, in dB, between the REUR and the stimulus SPL,
or stimulus band SPL.
Real-Ear Aided Response (
REAR
): SPL, or band SPL, in the ear canal for a given stimulus,
with a working hearing aid in place.
Real-Ear Aided Gain (
REAG
): Difference, in dB, between the REAR and the stimulus SPL, or
stimulus band SPL.
Real-Ear Saturation Response (
RESR
): The REAR obtained using a narrow-band signal at a
level high enough to saturate the hearing aid (usually 85 - 90 dB SPL).
Real-Ear-to-Coupler Difference (
RECD
): Difference, in dB, between the real-ear SPL and the
2cc coupler SPL produced by the same transducer driven by the same signal.
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 1 am the following day or at 1 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.
Switching left and right probe modules after calibration will result in the wrong calibration
curve being applied.
Calibration should be repeated if probe modules are switched or if a
probe-tube with different dimensions is installed.
Calibration of on-ear probe microphone
Ensure the probe microphone assembly to be calibrated is plugged into the appropriate
jack. See Microphone connection and On-ear calibration facts
1. Press <Tests>, then highlight & <PICK> [On-ear measures], then highlight & <PICK>
[Calibration].
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.
52
Summary of Contents for RM500SL
Page 1: ...RM500SL User s Guide Version 3 4 March 2010...
Page 9: ...RM500SL User s Guide Version 3 4 June 2011 EC Declaration of Conformity 9...
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Page 43: ...RM500SL User s Guide Version 3 4 June 2011 telecoil test 43...
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Page 78: ...RM500SL User s Guide Version 3 4 June 2011 Screen tour unaided screen 78...
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