Appendix C 199
Calibration
The FP35 provides you with a means to calibrate the system, the probe and cou-
pler microphones, and the insert earphone(s).
The system calibration of the FP35 should be done once a year, but the micro-
phones should be calibrated only when necessary. Even if you have determined
that the microphones are out of calibration, you should contact the factory or
your sales representative before calibrating the microphones. The reason for
taking this precaution is that the microphone calibration is stored in the micro-
phone connector rather than in the instrument. Because of this setup, the micro-
phones should not go out of calibration. If they do, it may indicate that some-
thing more is wrong, and simply calibrating the microphones might not correct
the problem.
Note: For best accuracy, allow the FP35 to stabilize to room temperature before
performing a system calibration. The FP35 will stabilize to room temperature if
it is left on for 15 minutes. The current internal temperature is displayed in the
Calibration Screen.
A. Calibrating the System
To calibrate the system:
1. From the Default Settings Menu press [F3] to enter the Calibration Menu.
2. Use the [∧, ∨] buttons to move the cursor next to “Calibrate System.”
3. Press [START/STOP]. The FP35 will confirm that you want to calibrate the
system.
4. Press [START/STOP] to begin the calibration, or press any other key to can-
cel. The FP35 will ask you to wait while the system is calibrating. Once cali-
bration is complete, the FP35 will return to the Calibration Menu.
5. Select “Store Calibration in EEROM” in the menu.
6. Press [START/STOP] twice. The system calibration is now complete and
stored.
Instructions for storing the system calibration are given at the end of this appen-
dix.
B. Checking the Microphone Calibration
Do the following procedure to determine if the coupler and probe microphones
are out of calibration.
