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Chapter 8 187
Spectrum Analysis
The FONIX FP35 can be used as a sound spectrum analyzer in either the cou-
pler (test box) or Real-Ear Test Modes. External sounds are measured through
the microphones and displayed in an amplitude-vs-frequency format. See
Section 5.6 for instructions on live speech testing.
8.1 Spectrum Analysis Measurements
Spectrum analysis measurements can be done in most measurement screens on
the FP35 analyzer using the composite, digital speech, or fast pure-tone signals.
If you are using a fast pure-tone sweep to take the spectrum analysis, measure-
ments will only be taken at the frequencies normally measured by the fast
sweep. If you have the Composite Option, it is recommended that you use the
composite signal to take spectrum analysis measurements.
Once you have enter the desired measurement screen and selected your signal
source with [F4], use the [
∨] key to turn the source amplitude to OFF. Now press
[START/STOP] to begin spectrum analysis testing.
8.2 Using the Spectrum Analysis Mode
You should find the following suggested applications clinically helpful, interest-
ing and fun.
A
pp licAtio n 1: m e A s u r i n g t h e o c c l u s i o n ef fec t o f A h e A r i n g Ai d .
This simple procedure will help you measure the occlusion effect of the hearing
aid on the wearer’s own voice. The spectrum analysis measurement will help
you judge the sometimes-uncomfortable feeling caused by the occlusion effect
of a hearing aid. You will be able to measure the effect and the improvements
made after venting adjustments have been made.
Suggested procedure:
1. Enter the REAL-EAR Mode.
2. Press [NEXT] or [BACK] until you enter the SPL Screen.
3. Use [F2] to select AIDED 1.
4. Choose COMP or FAST with [F4]. Press [
∨] repeatedly until the source is off.
5. Place the probe tube into the client’s ear (see Section 7.2.4).
6. Place the hearing aid in the client’s ear. The aid should be off.
7. Push the [START/STOP] key. Instruct the client to sustain the vowel sound
“eee.”