58 FONIX FP35 Hearing Aid Analyzer
1. Type of display. This will be either dB SPL (coupler output) or dB Gain (cou-
pler gain). Select between the two in [MENU].
2. Displays leveling status of the sound chamber. See Section 3.2 for more
information.
3. Displays the signal and weighting types used with the selected curve.
4. N.R. = Noise reduction. Select this in [MENU].
5. Status of reference microphone. Select this in [MENU].
6. RMS/HFA data: If a composite signal is selected, the RMS OUT will be dis-
played here. Otherwise, the selected HFA or SPA will be displayed. Press
[MENU] to select HFA/SPA frequencies.
7. Curve ID box. See Section 2.7.2 for more information.
8. Source Signal Statistics Box. The information in the box is dependent upon
signal type.
• COMP,DIGSPCH—DisplaystheRMSsourceamplitude.
• NORM,FAST,SHORT,SINGLE—Displaysthesourceamplitude,frequen-
cy, distortion, and output/gain.
3.2 Leveling the Sound Chamber
Leveling is the process by which the response of the sound chamber is mea-
sured and computer-corrected so that a “flat” sound field is achieved. Usually
leveling is performed using only the coupler measurement microphone.
However, a reference microphone can also be used that theoretically will make
the leveling (and measurement) process more accurate. The reference micro-
phone is available when the Real-Ear option is included on the FP35 or the
M300 two microphone setup is specifically ordered with a sound chamber-
only analyzer. For most clinical situations, leveling with only the measurement
microphone (described in Section 3.2.1) is adequate.
There are three level statuses:
LEVELED—Indicates the leveling process was correct within 2 dB.
UNLEVELED—Indicates the leveling process was incorrect by at least 6 dB, or
that the system has not yet been leveled.
<BLANK>—If the display is blank where the words LEVELED or UNLEVELED
usually appear, the leveling process was correct between 2 dB and 6 dB. You
should attempt to level again. However, if repeated attempts fail to reach a lev-
eled status, you can consider this status “good enough.”
Note: Sections 3.2.1 and 3.2.2 describe how to level the sound chamber in the
Coupler Multicurve screen. These procedures also work in the Coupler Target
and automated test sequence screens.
