introduction to the fonix 7000 hearing aid test system

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