1. New Features on the FONIX FP35 Hearing Aid Analyzer
Version 6.00

2. Hardware Features
Battery Current Drain
External Input (v5)
Line In

3. Software Features Improved Digital Speech
Test for Frequency-Shifting Hearing Aids
Modified NAL-NL1 Fitting Rule for low to moderate gain hearing aids
1/3 Octave Analysis

4. Improved Digital Speech
Digital Speech signal sometimes interfered with feedback management and other advanced features on some hearing aids
Modifications have been made to improve test results
New feature automatic with DIG SPCH is the selected input source

5. A little theory… Noise Reduction
Old Method
Sample from Microphone
Averaging to remove noise
Frequency Analysis
Great for eliminating momentary noise, but a problem when testing new, complex hearing aids with feedback management and other advanced features.

6. New Noise Reduction with Digital Speech and Spectrum Analysis
New Method
Sample from Microphone
Averaging to remove noise
Frequency Analysis
Should produce a smoother frequency response without interfering with feedback management software.
Also: Smoothing has been added to Digital Speech measurements in Coupler Multicurve.

7. Comparison of test results using Digital Speech
Version 5.01 software
Version 6.00 software

8. New Test for Freq-Shift Hearing Aids
Graph entire response of hearing aid to a pure-tone signal (default: 4000 Hz)
Peak response
Input signal
Choose DIG FS with F4 in Coupler Multicurve Screen to perform test

9. DIG FS showing no frequency shift

10. Modified NAL-NL1 Targets
Some customers have reported that NAL-NL1 targets are hard to fit with some moderate gain hearing aids
Competing analyzers have version of NAL-NL1 with less gain prescription
We have created a “MOD NAL” target that prescribes 3 dB per octave less gain than standard NAL-NL1
Both NAL-NL1 and MOD NAL are available in v6.00 software

11. Comparison of NAL-NL1 and MOD NAL
NAL-NL1 standard target
MOD NAL reduced target
Modified formula affects both Real-ear SPL and Real-ear Insertion Gain targets
Note: Audiogram used to create these targets is flat 30 dB HL

12. 100 Hz FFT vs Third Octave Analysis
100 Hz FFT analysis

13. First: Thought Experiment: 100 Hz vs 50 Hz Analysis
Think of the output of a frequency response as energy.
Each point on the response is a “bin.”
More bins = better resolution, less output per bin

14. 100 Hz FFT Analysis vs Third Octave
In Third Octave analysis, frequency response is divided into 17 different points: 200, 250, 315, 400, 500, 630, 800, 1000, 1250, 1600, 2000, 2500, 3150, 4000, 5000, 6300, and 8000
Third Octave analysis has been resolution in the low frequencies and less resolution in the high frequencies due to logarithmic scaling
All FONIX analyzers perform “100 Hz FFT” analysis
Frequency response is divided into 79 different points that are 100 Hz equidistant (200, 300, 400… 7900, 8000 Hz)
Difference between 100 Hz FFT and Third Octave analysis is 3 dB per octave

15. Important Notes
This 3 dB per octave difference only occurs when viewing results in terms of dB SPL (coupler or real-ear). Gain measurements are not affected.
This difference only occurs when using broadband signals. During a pure-tone sweep, only one “bin” is filled at a time, so the energy is not distributed.

16. Third Octave analysis on the FP35 analyzer
Available in Real-ear SPL and Coupler Multicurve test screens.

17. Visible Speech Updates
Speech signal input
RMS Output
Diamonds = Peak Pulsed Average Decay
Use a connected CD player or iPod for the input signal!