Real-Ear Measurements 153
5. Press [EXIT] to return to the real-ear measurement screen and follow the
directions in Section 5.7.3.2 to perform the IM distortion sweep.
5.7.4 Using the Reference Microphone
The larger microphone that sits on top of the client’s ear is always used for
leveling the sound field speaker. It can also be used in real-ear gain and inser-
tion gain measurements. When the reference microphone is turned on in the
Unaided and Aided measurement screen, or in the Insertion Gain screen, the
analyzer subtracts the reference microphone measurement, made just outside
the client’s ear, from the probe microphone measurement, made inside the cli-
ent’s ear in order to derive gain and insertion gain results.
When the reference microphone is turned off during these measurements, the
FP35 analyzer assumes that the sound field outside the client’s ear is absolutely
perfect, and just relies on the leveling information to achieve the gain (or inser-
tion gain) response. While this can lead to smoother response curves, the mea-
surement will not be quite as accurate. For most purposes, it is recommended to
perform gain and insertion gain measurements with the reference microphone
on. In a noisy testing environment, it might be advantageous to turn the refer-
ence microphone off in order to get a smoother response.
To change the reference microphone status:
1. Press [MENU] in the real-ear measurement screen.
2. Use [
∨, ∧] to select REF MIC.
3. Use [<, >] to turn the reference microphone ON or OFF.
4. Press [EXIT] to return to the measurement screen.
5.7.5 Viewing Target Data
You can view the numerical data of your response curves with the DATA/
GRAPH selection in the main local menu of the real-ear measurement screen
and using [F2] to select the desired curve. However, if you want to view the
numerical data of the target curve itself, you must use the TABULATION field
in the Advanced real-ear menu. This will add a table to the right of the real-ear
measurement graph, displaying the target in numerical format.
The USER LEVEL must be set to ADVANCED in the Default Settings menu. See
Section 2.3.2 for details.
To view the target in numerical format:
1. Press [MENU] to enter the main real-ear menu.
2. Press [NEXT] to enter the Advanced real-ear menu.
3. Use [
∨, ∧] to select TABULATION.
4. Use [<, >] to select TARGET.
5. Use [EXIT] to return to the real-ear measurement screen. The target data will
now be displayed. See Figure 5.7.5.
