introduction to the fonix 7000 hearing aid test system
DESCRIPTION
Introduction to the FONIX 7000 Hearing Aid Test System. Software version 1.60. Outline. Coupler Measurements Basic (ANSI, Coupler Multicurve) Testing Digital Aids Open Fit Coupler Measuring directionality Automation Advanced Coupler Real-Ear Measurements Entering an audiogram - PowerPoint PPT PresentationTRANSCRIPT
Introduction to the FONIX 7000 Hearing Aid Test System
Software version 1.60
Outline
Coupler Measurements Basic (ANSI, Coupler Multicurve) Testing Digital Aids Open Fit Coupler Measuring directionality Automation Advanced Coupler
Real-Ear Measurements Entering an audiogram Insertion Gain Testing directionality Real-ear SPL Visible Speech Testing Open Fit hearing aids
Default Settings
Basic Coupler Measurements
ANSI 03 — F4Coupler Multicurve — F1
ANSI 03 Settings
Choose ear
Aid type
Frequencies Telecoil
ANSI 03 Results
OSPL90
Response curve
Max
OSPL90-HFA
Distortion
FOG
TelecoilEIN
Battery current
Telecoil I/O curves
Attack & Release
Coupler Multicurve Features
Realistic frequency response measurements
Variety of signal types: Composite, Digital Speech, Pure-tone sweeps
Display 10 different curves simultaneously
Switch back and forth between gain and output. All curves translated.
Coupler Screen Operation
Choose Ear
Select Curve Source Type
Amplitude
Example
50 dB
60 dB
70 dB
80 dB
Testing Digital Aids
Digital SpeechType of Composite signalModulated to allow testing of noise
reducing digital aidsUsed with ANSI or ICRA speech spectra
Example of digital aid test
Digital Speech
Composite
Testing Open Fit Hearing Aids
The Open Fit Coupler was designed toProvide a realistic response for open fit
hearing aids.Provide an easy mechanism for attaching
an open fit hearing aid to a couplerThe Open Fit Coupler is a non-standard
sized coupler not designed to test to manufacturing specifications
Attaching the Open Fit Coupler
Testing Directionality
Use chamber design to perform “forward” and “reverse” measurements to obtain directional advantage
Chamber speaker mounted at 45 degree angle, pointing towards left side of chamber
Forward/Reverse Positioning
Forward positioning with hearing aid pointed towards sound chamber speaker
Reverse positioning with hearing aid pointed away from sound chamber speaker
Directional Advantage
Forward measurement
Reverse measurement
6 dB RMS Difference
Coupler Automation
Set up own test sequenceSelect signal type for each curveSelect signal amplitude for each curveAdd any desired pauses in test
sequenceSave and auto load test sequence
Programming Auto Mode
F6 — Program Mode
Help window w/instruction
s
F5 — Source TypeAmplitude
START
STOP
Advance to next curve without pause
Advance to next curve with pause
Example of Auto Test
Digital Speech @ 50, 65, 80 dB
Pure-tone sweep @ 90 dB
F6 — Fully Automatic mode
Saving and Loading Settings
Automatically load saved curve group and put analyzer in Auto Mode
Advanced Coupler
Battery Current [F1]Coupler I/O [F2]Attack & Release [F3]Enhanced DSP [F4]
Function key operations available in the Advanced Coupler Navigation Screen
Battery Current Screen
Measure Battery Current as a function of frequency
Measure Battery Current as a function of amplitude
Estimate battery life of hearing aid
Battery Current Test
Battery current by freq
Battery current by amp
Coupler I/O
Composite or Pure-tone source typesAny Freq from 200 to 8000 Hz in 100 Hz
intervalsDisplay results in Output (SPL) or GainGraph and data results given
Coupler I/O Test Results
Frequency
Test Results
F5: Source Type
Attack & Release Test Screen
Visual time graph of Attack and Release tests
Scale graphs independently to zoom in on results
Use Composite or Pure-toneChoose any frequency from 200-8000
Hz in 100 Hz intervalsCustomize amplitudes used in tests
Attack & Release Results
Frequency
F5: Source type
F6 & F7: Change graph scales
Enhanced DSP
Designed to measure the "group delay" of a DSP aid. In other words, the actual digital processing time of a hearing aid. 0 ms for analog aids 1-12 ms for DSP Great way to check if aid is analog or DSP
Also tests the "phase" of a hearing aid. This is useful for binaural fittings. Are the aids working together?
Technical Details: Group Delay
An impulse signal is delivered to the hearing aid. The time of the maximum peak of the response is considered the group delay. The 7000 system delay is subtracted from this value to obtain the final measurement.
Technical Details: Phase
One pulse of a 1000 Hz cosine signal is delivered to the aid. This signal is 1 msec long. The first 20 msec of the aid's response to the signal is displayed in graphical format.
Example
Group Delay Phase
Basic Real-Ear measurements
F1 — Audiogram Entry
F2 — Target EditF3 — Insertion Gain
F4 — Real-ear SPL
Use the function keys to enter a screen
F5 — Visible Speech
Entering an audiogram
F1 — Select ear
F2 — Select HTL/UCL/Bone
F3 — Predict UCLs
Real-Ear SPL only
Adjust amplitude
Adjust frequency
Insertion Gain features
Unaided measurementUp to 4 aided measurementsGives up to 4 insertion gain
measurementsOperation similar to coupler screen
Insertion Gain screen
F1 — Select ear F2 — Select curveF5 — Select source type
Select amplitude
Insertion Gain
Target
Unaided
Aided
Step 1: Setup
Speaker should be 12 inches from patient at 45
degree angle
Reference Mic
Probe Mic
Step 2: Level
LEVEL
Step 3: Unaided Measurement
Peak at 3 kHz
Negative response at 6 kHz shows probe tube could probably be inserted more deeply
F2 - REUR 1 F5 - DigSpeech
Amplitude
START
STOP
Step 4: Aided/IG measurements
F2 — REAR 2
IG Target
IG curve
Multiple Aided/IG measures
Testing Directionality
Directional Advantage
CRV 2 — Forward response
CRV 1 — Reverse response
Real-Ear SPL screen
Check low inputs are above thresholdsCheck average inputs meet targetCheck loud inputs are below UCLsAuto-adjusting REUR shows
amplification benefit at all levelsGives overall look at hearing aid fittingOperation similar to coupler & IG
screens
SPL operation
T = Thresholds
U = UCLs
H, M, L = Targets
Auto-Adjusting REUR Option
REUR 1 automatically adjusts when the 80 dB REAR 4 curve is selected
REUR 1 adjusted to 80 dB
REAR 4 @ 80 dB
Visible Speech
Use live speech signalReal-time response (during test)Average responseMinimum and maximum response per
frequency for the length of the testHTLsUCLsAll on one graph in dB SPL
Visible Speech: Before Test
UCLs
HTLs
Targets
Visible Speech: Test Results
Max boundary
Avg Response
Min boundary
HTLs
UCLs (off screen)
Open Fit Hearing Aids
Some Open Fit hearing aids interfere with the reference microphone measurements outside the ear.
Disable the Reference Microphone in the local menu to perform real-ear on these hearing aids.
Real-ear targets may prescribe low frequency amplification unsuitable for open fit hearing aids.
Default Settings
Press [MENU] from the Opening Screen to enter the Setup Menu
Use [F1] in the Setup Menu to choose between:General SettingsCoupler SettingsReal-ear Settings