Frye FONIX FP35 Quick Reference Manual

FONIX

Quick Reference Guide

FP35

®

©2008 Frye Electronics, Inc. All rights reserved

P/N 010-0021-04

Contents

Chapter 1: Introduction................................................................................1

1.1 Front Panel Layout .....................................................................................1

1.2 Key Operation .........................................................................................2

1.2.1 Navigating through the FP35 screens ............................................................2

1.2.2 Getting help .....................................................................................2

1.2.3 Using the local menus ...........................................................................3

1.3 Default Settings ........................................................................................4

1.4 User Level Mode .......................................................................................6

1.5 Printing ................................................................................................6

Chapter 2: Coupler Multicurve .......................................................................7

2.1 Leveling................................................................................................7

2.2 Frequency Response Measurements...................................................................8

2.2.1 Explaining the signals............................................................................8

2.2.2 Performing a measurement......................................................................9

2.2.3 Testing Digital Aids .............................................................................10

2.2.4 Testing Harmonic Distortion ....................................................................11

2.2.5 Testing Intermodulation Distortion .............................................................12

Chapter 3: Automated Test Sequences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

3.1 The ANSI Sequence ...................................................................................15

3.1.1 Setting up for ANSI testing ......................................................................15

3.1.2 Running an ANSI Test ...........................................................................16

3.1.3 Testing Digital Hearing Aids.....................................................................18

3.2 IEC Testing............................................................................................18

3.2.1 Setting Up the Hearing Aid for Testing ..........................................................18

3.2.2 Running an IEC Test ............................................................................19

Chapter 4: Real-Ear Measurements.................................................................21

4.1 Introduction..........................................................................................21

4.1.1 Real-Ear Screens................................................................................21

4.1.2 Navigation ......................................................................................21

4.2 Real-Ear Setup .......................................................................................22

4.2.1 General Setup ..................................................................................22

4.2.2 Internal Speaker Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

4.2.3 External Speaker Setup.........................................................................24

4.2.4 Placing the Probe Tube .........................................................................25

4.2.5 Placing the Sound Field Speaker ...............................................................26

4.2.6 Leveling the Sound Field Speaker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

4.3 Audiogram Entry Screen—Creating A Target .........................................................28

4.3.1 Entering the Audiogram Screen.................................................................28

4.3.2 Entering Audiometric Information & Creating A Target..........................................28

iv FONIX FP35 Hearing Aid Analyzer

4.3.3 Creating an NAL-NL1 Target.....................................................................29

4.3.4 Measuring the Real-Ear to Coupler Difference..................................................30

4.3.4.1 Analyzer Setup for RECD ................................................................30

4.3.4.2 Client Setup for RECD ...................................................................31

4.3.4.3 Taking the RECD Measurement..........................................................32

4.4 Insertion Gain Testing ................................................................................32

4.4.1 Measuring the Unaided Response..............................................................34

4.4.2 Measuring the Aided Response ................................................................35

4.4.3 Testing Automatically...........................................................................36

4.4.4 Testing Directional Hearing Aids................................................................36

4.5 Testing in the SPL Screen .............................................................................39

4.5.1 Viewing the SPL Display ........................................................................40

4.5.2 Running an SPL Test ............................................................................40

4.5.3 Testing Automatically...........................................................................41

4.6 Live Speech Testing...................................................................................42

4.6.1 Using Speech as a Test Signal ...................................................................42

4.6.2 Measuring the occlusion effect..................................................................43

Chapter 5: 2-CC Targets...............................................................................45

5.1 Target Creation........................................................................................46

5.2 Coupler Target ........................................................................................46

5.3 Coupler EarSim .......................................................................................47

Index ....................................................................................................49

Chapter 1 1

Introduction

Welcome to the FP35 quick reference guide. This manual explains all the major
features of the FP35 analyzer, but is not a comprehensive guide to all of its
functions. If you require further explanation or details, see the FP35 Operator’s
Manual.

1.1 Front Panel Layout

Figure 1.1—Front panel

The following is a short explanation of the basic functions of the keys on the
FP35 front panel.

1. Print: Prints the current screen.

2. Help: Open the help window for the displayed screen.

3. Reset: Resets the analyzer, deleting measurements and returning many set­tings to their default selections.

4. Operate: Powers the analyzer on and off.

5. Function keys: F1—F5: Perform various functions, depending upon the dis­played screen.

2 FONIX FP35 Quick Reference Guide

6. Menu: Opens the local menu or the default settings menu.

7. Exit: Exits from a screen.

8. Back & Next: Moves to the next measurement screen or through the menu
system.

9. Arrow keys (up, down, right, left): Changes amplitude and frequency selec­tions when in a measurement screen, and menu selections when in a local
menu.

10. Start/Stop: Starts and stops a measurement.

1.2 Key Operation

This section describes the basic operation of the keys most often used on the
FP35 analyzer. These keys are used to navigate through the different screens
and pull up useful information and settings.

1.2.1 Navigating through the FP-35 screens

Most of the navigation through the FP35’s screens are done with the function
keys, the [NEXT] and [BACK] keys, and the [EXIT] key.

From the Opening screen, the function keys will take you to different measure­ment screens. For instance, [F3] will take you to one of the Coupler Multicurve
screens, and [F2] will take you to one of the real-ear screens. The function of
each key is displayed on the screen above the key.

The [NEXT] and [BACK] keys are used to take you to related screens. For
instance, if you are in the Audiogram Entry screen, pressing [NEXT] will take
you to the Real-ear SPL screen. [NEXT] and [BACK] are also used for navigating
through the different menu levels.

The [EXIT] key is used to exit from the current screen. Pressing [EXIT] will
never delete any measurements.

The [RESET] key can be used to return to the Opening screen. However, press­ing [RESET] will delete measurements and reset settings that you may have
changed. Unless this is your intent, it is recommended to use the [EXIT] key
instead of [RESET].

1.2.2 Getting help

Pressing the [HELP] button will open a help window for the currently displayed
screen. For instance, if you are in the Coupler Multicurve screen, pressing
[HELP] will pop up a window containing a short explanation of all the com­mands available in the Coupler Multicurve screen. See Figure 1.2.2.

1: Introduction 3

Figure 1.2.2—Help Screen

1.2.3 Using the local menus

Pressing the [MENU] button when in a measurement screen will open the local
menu containing selection that pertain to the current screen. For instance, press­ing [MENU] while in the ANSI 96 screen will open a local menu containing
ANSI 96 selections. See Figure 1.2.3.

Advanced features and fine-tuning selections are often “hidden” away in an
advanced menu reachable using the [NEXT] and [BACK] keys. Look at the title
bar of the local menu to see if the [NEXT] and [BACK] keys are active in the dis­played local menu.

4 FONIX FP35 Quick Reference Guide

Figure 1.2.3—Local Menu

1.3 Default Settings

It’s possible to change the default selections of many of the FP35 analyzer’s set­tings. For instance, you might want to select Digital Speech as your default real­ear source type, or have the default source levels of CRV 1-4 be 50, 65, 80, and
90 dB SPL.

Three different sets of default settings can be saved into the FP35 analyzer’s per­manent memory. This allows you to have different default settings for different
clinicians in your office or for different types of hearing aid technology.

To save a setting configuration:

1. Press [MENU] from the Opening screen. This opens the Default Settings
menu. See Figure 1.3.

2. Use [F2], if desired, to select the desired SETTINGS number you want to
save your settings to. Choose between SETTINGS 1, SETTINGS 2, and
SETTINGS 3.

3. Use the arrow keys to make any changes to the displayed selections. The
up/down arrows move between selections. The right/left arrows change the
selection. Use the [START/STOP] key to jump ahead to the next group of
selections.

4. Press [NEXT] to enter the next Default Settings menu, and repeat the process
of setting up everything just the way you like it.

1: Introduction 5

5. Press [NEXT] to enter the final Default Settings menu. Use the arrow keys to
set up your selections.

6. Press [F5] to store all three menus into the SETTINGS number displayed
above [F2].

To switch to a different saved setting configuration:

• Use[F1]fromtheOpeningscreentoswitchbetweenSETTINGS1,2,&3.

—or—

• Press[MENU]fromtheOpeningscreentoopentheDefaultSettings

menu. Use [F2] to switch between SETTINGS 1, 2, and 3. Press [EXIT] to
return to the Opening screen.

Figure 1.3—Default Settings Menu

6 FONIX FP35 Quick Reference Guide

1.4 User Level Mode

The FP35 analyzer has two user levels: EASY and ADVANCED. In Easy Mode,
the measurement screens contain a little less information, but have a cleaner
look. The local menus also contain fewer settings so that the user can focus on
only the most important ones that are used in day to day testing activities. All
of the operations in this Quick Reference Manual assume the user is in EASY
mode, which is the factory default user level.

To change the USER LEVEL:

1. Press [MENU] from the Opening screen to enter the Default Settings menu.

2. Press [NEXT] to go to the Advanced Default Settings menu.

3. Use the [

4. Use the [
ADVANCED.

5. Use [F5] to save the setting, if desired.

5, 6] keys to select USER LEVEL under General Settings.

4] key to select the setting. Choose between EASY and

1.5 Printing

The FP35 analyzer comes equipped with an internal thermal printer so that
the ability to print a hard copy of your results is always available. The thermal
printer prints a clear, easy-to-read image of the display. You can also hook up
an external printer to print your results on normal office paper. You can use
any external printer that supports HP PCL (Hewlett Packard Printer Computer
Language) version 3.0 and above.

The general operation of the FP35 printer is easy:

• Press[PRINT/FEED]toprintanyscreen.

• Press[PRINT/FEED]againtostopprintinginthemiddleofaprintjob.

This will work even when the screen goes dark.

• Pressandholddownthe[PRINT/FEED]buttontofeedthepaper.

If you are in the middle of a test, and you want to switch between using the
internal and the external printer in the local screen, without changing the
default printer:

1. Press [MENU] from any test screen.

2. Press [NEXT] to enter the Advanced Menu.

3. Select PRINTER with the [

4. Select either INTERNAL or EXTERNAL with the [

5. Press [EXIT] to return to the test screen.

6] key.

4] key.

Chapter 2 7

Coupler Multicurve

In the Coupler Multicurve screen, you can view curves in dB SPL or dB Gain,
and run them with pure-tone, Composite, and Digital Speech signals (the latter
two are only available with the Composite Option.) Up to four curves can be
measured and displayed at the same time.

From the Opening screen of the FP35, enter the Coupler Multicurve screen by
pressing [F3].

2.1 Leveling

Leveling is the process by which the response of the sound chamber is mea­sured and computer-corrected so that a “flat” sound field is achieved. In most
cases, leveling is performed using only the measurement microphone. This type
of leveling is accurate enough for most clinicial tests. See the Operator’s Manual
for information on leveling using the reference microphone.

1. Enter the Coupler Multicurve screen by pressing [F3] in the Opening
screen.

2. Open the sound chamber and place the coupler microphone at the center
of the speaker cone in the sound chamber.

If the microphone cables are not positioned properly, the chamber lid can

pinch, and eventually damage them. Avoid damage by placing the cables
between the arrows at the bottom of the speaker face. The foam on the
chamber lid is thicker and softer in this area, offering more protection.

3. Place the coupler that you will be using inside the chamber next to the
coupler microphone. This is necessary because of the small volume of the
FP35 internal sound chamber, and measurement results, particularly in
the high frequencies, could be affected by the space the coupler takes up
inside the chamber. See Figure 2.1.

4. Close the sound chamber lid.

5. Make sure the environment is as quiet as possible.

6. Press [F5], followed by [START/STOP], to level the sound chamber.

8 FONIX FP35 Quick Reference Guide

Figure 2.1—Leveling setup

Leveling is not automatically saved into the analyzer’s permanent memory. If
you want to avoid releveling the chamber after you turn off the analyzer and
turn it back on again, you will need to save the leveling.

1. Press [MENU] from the Opening screen to enter the Default Settings
Menu.

2. Press [F3] to enter the Calibration Menu.

3. Use the [
Leveling in EEROM”

4. Press [START/STOP]. The FP35 will confirm that you want to store the
leveling.

5. Press [START/STOP] again to proceed.

6. Press [EXIT] twice to return to the Opening Screen.

5, 6] keys to move the cursor to the selection “Store Chamber

2.2 Frequency Response Measurements

The main purpose of the Coupler Multicurve screen is to perform frequency
response measurements. This section contains a short description of the signal
types available in this screen and a basic explanation of how to perform fre­quency response measurements.

2.2.1 Explaining the signals

By default, the FP35 analyzer comes with three types of pure-tone sweeps:

• NORMAL: single sweep containing 49 frequencies

• FAST: continuing sweeps containing 16 frequencies

• SHORT: single sweep containing 10 frequencies

• LONG:singlesweepcontaining64frequencies

2: Coupler Multicurve 9

When the Composite/Digital Speech Option is ordered, the FP35 analyzer will
also include these signals:

• COMP: broadband speech-weighted signal

• DIGSPCH: modulated, broadband, speech-weighted signal for testing

digital hearing aids.

You can use any of these signal types when performing frequency response mea­surements in the Coupler Multicurve screen. If you have the Composite/Digital
Speech Option, it is recommended to use DIG SPEECH for most measurements.
If you do not have that option, use FAST if you want a real-time-like measure­ment or NORMAL for a detailed frequency response.

For a more detailed explanation of these signal types, see the FP35 Operator’s
Manual.

2.2.2 Performing a measurement

Measuring the frequency response of a hearing aid is very straight-forward in
the Coupler Multicurve screen.

1. Enter the Coupler Multicurve screeen by pressing [F3] in the Opening
screen.

2. Level the sound chamber, if necessary, as explained in Section 2.1.

3. Attach the hearing aid to the coupler (see the FP35 Operator’s manual for
details), and place the assembly in the sound chamber.

4. Close the sound chamber lid.

5. Select the source type you want to use by pressing [F4]. You can either press
[F4] repeatedly until your desired source type appears on the screen above
the [F4], or you can press and hold the [F4] key to bring up a pop-up menu
containing all the selections. If you bring up a pop-up menu, use the
[

5, 6] keys to make your selection and the [START/STOP] key to close the

menu.

6. Use the [

7. Press [START/STOP] to begin the measurement. If you are using the COMP,
DIG SPCH, or FAST source type, press [START/STOP] again to stop the mea­surement when it has stabilized. See Figure 2.2.2.

8. Press [F2] to select CRV 2 and repeat steps 5-7 to perform a second frequen­cy response measurement.

A total of four frequency response measurements can be made in the Coupler
Multicurve screen in this fashion.

5, 6] keys to select the designed source amplitude.

10 FONIX FP35 Quick Reference Guide

Figure 2.2.2—Frequency response measurement

2.2.3 Testing Digital Aids

The best way to get an accurate frequency response of a digital hearing aid is
to use the Digital Speech signal. It’s also useful to test the digital aid with the
Composite signal. A comparison of these two curves will show you the amount
of noise suppression in the digital circuit—some aids will show a lot of differ­ence between a modulated and a steady state signal. Other aids will show no
difference.

The Composite/Digital Speech Option is required for this test.

1. Follow the instructions in Section 2.2.2 to obtain a Digital Speech frequency
response. In step 5, make sure to choose DIG SPCH.

2. Press [F2] to select CRV 2.

3. Use [F4] to select COMP.

4. Press [START/STOP] to start the Composite measurement. Leave the signal
on for at least fifteen seconds, giving the aid plenty of time to adjust to the
steady-state signal.

5. Press [START/STOP] again to stop the test.

6. Compare CRV 1, made with Digital Speech, to CRV 2, made with the
Composite signal. If the aid has noise suppression, CRV 2 should show less
amplification than CRV 1. See Figure 2.2.3

2: Coupler Multicurve 11

Figure 2.2.3—Digital speech curve comparison

2.2.4 Testing Harmonic Distortion

Harmonic distortion occurs when a hearing aid clips the peak of a pure-tone
input signal, resulting in artifacts at harmonics (integer multiples) of that input
signal. For example, if you present a 500 Hz tone to the hearing aid, distortion
artifacts could occur at 1000 Hz and 1500 Hz.

Definitions:

• 2NDHarmonic:Energyofthesecondharmonicortwicethepresentedfre­quency

• 3RDHarmonic:Energyofthethirdharmonicorthreetimesthepresented

frequency

• TOTAL:Combined2NDand3RDharmonicdistortion

See the FP35 Operator’s manual for more details. To perform a harmonic distor­tion measurement:

1. Enter the Coupler Multicurve curve screen by using [F3] from the Opening
screen.

2. Set up the hearing aid in the usual way. Make sure to close the sound cham­ber lid.

3. Press [MENU] to open the Coupler Multicurve local menu.

12 FONIX FP35 Quick Reference Guide

4. Use the [5, 6] keys to select DISTORTION.

5. Use [

6. Press [EXIT] to close the local menu.

7. Use [F4] to select NORM.

8. Use the [

9. Press [START/STOP] to run the pure-tone sweep. When the measurement

10. Look at the bars at the bottom of the graph. The scaling for these bars is on

3, 4] to select the type of harmonic distortion measurement you

want to make. When in doubt, select TOTAL.

5, 6] keys to select the source amplitude. When in doubt, choose

65 dB SPL.

has finished, it will automatically stop.

the right side of the graph. This is the amount of harmonic distortion mea­sured with the pure-tone sweep. See Figure 2.2.4.

Figure 2.2.4—Harmonic distortion measurement

2.2.5 Testing Intermodulation Distortion

Intermodulation (IM) distortion occurs when more than one frequency is pres­ent in the source signal and those frequencies combine to create new frequen­cies not actually present in the source. IM distortion is visible as jagged peaks in
the frequency response of the hearing aid when a Composite or Digital Speech
source type is used.

2: Coupler Multicurve 13

In the FP35 IM Distortion test, the analyzer presents two tones simultaneously.
The frequency distance between these two tones is set by the user. Any ampli­tudes found at frequencies other than the original two tones is considered dis­tortion. Just as when a harmonic distortion measurement is run, the analyzer
sweeps the tones across the entire frequency range—the only difference is that
two tones are used at a time instead of only one, as in a pure-tone sweep. See
the FP35 Operator’s Manual for more details.

To run the IM test:

1. Set up the analyzer for coupler testing as usual.

2. Enter the Coupler Multicurve screen by pressing [F3] from the Opening
screen.

3. Press [MENU] to enter the local menu.

4. Use the [

5. Use [
TOTAL to get the most IM distortion data.

6. Press [NEXT] to go to the Advanced Coupler Multicurve screen.

7. Use the [

8. Use [
surement.

9. Press [EXIT] to close the local menu.

10. Press and hold down the [F4] key for half a second. This will bring up a
pop-up menu containing all the available source types.

11. Use the [

12. Press [START/STOP] to complete the selection and close the pop-up menu.

13. Press [START/STOP] again to perform the IM distortion sweep. The test will
stop automatically when it is finished. See Figure 2.2.5.

5, 6] keys to select DISTORTION.

3, 4] to select the type of IM distortion sweep you want to make. Use

5, 6] keys to select IM FREQ DIFF.

3, 4] to select the difference between the two tones used in the mea-

5, 6] keys to select DIST.

14 FONIX FP35 Quick Reference Guide

Figure 2.2.5—IM distortion measurement

Chapter 3 15

Automated Test Sequences

3.1 The ANSI Sequence

The ANSI test sequence allows you to test hearing aids according to the ANSI
S3.22 standard. You can use the ANSI test to control the quality of the hearing
aids that you dispense. Compare the manufacturer’s specifications with your
own ANSI measurements of an aid. If they do not conform within expected tol­erances, you can contact the manufacturer.

There are two versions of the ANSI S3.22 standard on the FP35 analyzer: ANSI
96 and ANSI 03. As of the printing of this manual, ANSI 96 is the current stan­dard to which the FDA requires hearing aid manufacturers to label their hearing
aids. ANSI 03 will eventually replace this standard, but the date of the switch­over is not yet known.

The [F4] or [F5] key in the Opening screen is normally used for entering the
ANSI 96 screen. Press whichever key is labeled as “ANSI 96.”

To switch between ANSI 96 and ANSI 03, first enter the ANSI test screen
by using either [F4] or [F5] from the Opening screen: select the function key
labeled either ANSI 96 or ANSI 03. From the ANSI screen, push [MENU] to
open the local menu. Use [
between S3.22-1996 and S3.22-2003. After switching between the standards,

you must press [MENU] twice to update the local menu if you want to make
any further menu changes.

3.1.1 Setting up for ANSI testing

The hearing aid controls must be set to conform with ANSI requirements for the
test results to be valid.

1. Set the controls on the aid (except for the compression controls) to give the
greatest possible output and gain.

2. Set the aid for the widest frequency response range.

3. For ANSI 96, set AGC aids to achieve the greatest possible compression or as
otherwise specified by the manufacturer. For ANSI 03, set the compression
controls to have minimum effect or as specified by the manufacturer.

4. If you are testing a digital hearing aid, put it in “test” mode if possible.

5. Set the gain control to full-on.

6. Set the aid up in the sound chamber as usual.

5,6] to select ANSI TEST and [3,4] to switch

16 FONIX FP35 Quick Reference Guide

Setting up a Linear Aid

For ANSI 96, use [F1] to select LINEAR 50 or LINEAR 60. Your selection should
be based upon manufacturer specifications. If the specifications are unavailable,
use:

• 50 dB for aids with high gain and relatively low output.

• 60dBallotheraids.

In ANSI 03, the full-on gain measurement is always taken at 50 dB SPL, so this
selection is not avialable.

Setting up an AGC Aid

Use [F1] to select AGC or ADAPTIVE AGC.

When you run the ANSI sequence on an AGC aid, you may run up to five dif­ferent input/output curves. The frequencies that you can choose from are 250,
500, 1000, 2000, and 4000 Hz. Choosing AGC or ADAPTIVE AGC with [F1] will
result in additional selections appearing above [F2] and [F3] that let you control
the input/output settings.

Push [F2] to toggle through the frequencies. Use [F3] to turn the input/output
curve for the current frequency on or off.

Press [NEXT] to see the ANSI I/O Screen. If you haven’t yet run an ANSI test,
the I/O curve selection box will show which curves you have selected to test.

3.1.2 Running an ANSI Test

1. Press [START/STOP] to begin the test.

2. Usually the FP35 will pause during the measurement process in order to let
you adjust the gain of the hearing aid to the reference test position.

a. Lift the sound chamber lid and adjust the gain control of the aid until the

MEASURED gain matches TARGET gain.
b. Close the sound chamber lid when finished.
c. The MEASURED gain should be within 1 dB of the TARGET gain.

3. Push [START/STOP] to continue the test. If you are measuring to ANSI 03
and have set the aid type to AGC or ADAPTIVE, the analyzer will pause
again after several measurements have been taken. Adjust the AGC controls
of the aid to have maximum effect (or as specified by the manufacturer) and
press [START/STOP] again to complete the test sequence. The analyzer will
not pause if the ANSI TEST is set to S3.22-1996 or if AGC SWITCHING is
OFF in the local menu. (See Section 4.1.5)

4. Press [NEXT] to view the ANSI 96 I/O Screen for AGC aids.

5. Press [PRINT] for a hard copy of the results.

3: Automated Test Sequences 17

Figure 3.1.2A—ANSI test completed

Figure 3.1.2B—ANSI 96 test, I/O Screen

18 FONIX FP35 Quick Reference Guide

3.1.3 Testing Digital Hearing Aids

The ANSI S3.22-1996 “labeling” standard for hearing aids was not designed
with digital hearing aids in mind. In fact, most of the testing methods employed
by ANSI 96 have been around since the 1970s. However, since ANSI is a stan­dard, in order to conform to that standard, it must use only the testing tech­niques outlined in the standard. For this reason, the FP35 has no provisions for
incorporating composite or digital speech into the ANSI 96 standard.

In order to test digital hearing aids with “noise reduction” or “speech enhance­ment” features to the ANSI 96 standard, put the aid in “test” mode via its pro­gramming software and do the steps outlined in Section 3.1.2.

In order to get an accurate picture of the aid’s actual performance when it goes
home with your client, put the aid in the mode you will use for that client, and
perform response curve measurements in the coupler and in the real-ear via the
procedures described in Chapter 2 and Chapter 4 using the digital speech (DIG
SPCH) signal source.

3.2 IEC Testing

The IEC 118-7 standard was designed by the International Electrotechnical
Commission to assess hearing aids. The performance part of that standard can
be included as an automated sequence on your FP35.

The [F4] or [F5] key in the Opening screen is normally used for entering the
IEC screen. Press whichever key is labeled as “IEC.”

3.2.1 Setting Up the Hearing Aid for Testing

1. Set the controls on the aid (except for compression controls) to give the
maximum output and gain.

2. Set the aid for the widest frequency response range.

3. Set AGC aids for maximum compression.

4. Make sure that the gain control of the aid is full on.

5. Set the aid up in the sound chamber as usual.

6. Press [F1] to select aid type.

7. Press [F2] to select between a full-on gain measurement at 50 dB or at 60
dB.

8. Press [F3] to select a reference frequency of 1600 Hz or 2500 Hz. Select 2500
Hz for high frequency emphasis aids.

9. Press [F4] to choose whether to test an I/O curve during the test sequence.

3: Automated Test Sequences 19

3.2.2 Running an IEC Test

1. Level the sound chamber, if needed.

2. Push the [START/STOP] button.

3. The FP35 will pause during the measurement process in order to let you
adjust the gain of the hearing aid to the reference test position.

a. Lift the sound chamber lid and adjust the gain control of the aid until the

MEASURED gain matches TARGET gain.
b. Close the sound chamber lid when finished.
c. The MEASURED gain should be within 1 dB of the TARGET gain.

4. Push [START/STOP] to complete the test.

5. Press [NEXT] to view the I/O Screen.

6. Press [PRINT] for a hard copy of the results.

Figure 3.2.2A—IEC test completed

20 FONIX FP35 Quick Reference Guide

Figure 3.2.2B—IEC test results, I/O Screen

Chapter 4 21

Real-Ear Measurements

4.1 Introduction

When the Real-Ear Option is ordered with your FP35 analyzer, you can test the
hearing aid inside the patient’s ear using the probe microphone. When performed
correctly, this is the most accurate measurement available of the hearing aid’s
performance because it is performed using the patient’s own ear canal resonance.

In the real-ear measurement screens, you can input an audiogram, generate a target,
and take insertion gain and SPL measurements.

4.1.1 Real-Ear Screens

There are four different real-ear screens on the FP35 analyzer. One of these screens
is for creating a real-ear target: the Audiogram Entry Screen. The other three screens
are for performing real-ear measurements: the Unaided & Aided, Insertion Gain, and
SPL Screen—the insertion-gain technique for fitting hearing aids has been separated
into two separate screens to make it easy to distinguish between gain curves and
insertion gain curves.

Audiogram Entry—Enter your audiograms, choose your fitting rule, perform RECD
and REDD measurements, and generate a target in this screen.

Real-Ear SPL—View thresholds, UCLs, targets, and aided measurements in real-ear
SPL on one screen. This gives you a complete picture of the client’s hearing range
and where the aided responses are falling in that range.

Real-Ear Unaided & Aided—Measure and display your client’s unaided and aided
measurements. You can run up to three separate aided curves and display them all
on the same screen.

Insertion Gain—Measure and view your client’s unaided and insertion gain
measurements. Up to three insertion gain measurements can be displayed at one
time.

4.1.2 Navigation

To enter the Real-Ear Mode, press [F2] from the Opening Screen of the FP35. This
will one of the real-ear screens. To navigate through the four screens of the Real­Ear Mode, press the [NEXT] and [BACK] keys. Continuously pressing one of these
keys will cycle you through the four choices, eventually bringing you back to screen
where you started. See Figure 4.1.2.

To leave the Real-Ear Mode, press [EXIT] at any time.

22 FONIX FP35 Quick Reference Guide

Audiogram

Entry

Real-Ear SPL

Real Ear

Unaided & Aided

Insertion Gain

Top View

Speaker

(45 degrees)

12"

Reference Mic

Probe Mic

12"

Reference Mic

Probe Mic

Front View

Speaker

(45 degrees)

FONIX FP35 Hearing Aid Analyzer

Figure 4.1.2—Real-ear navigation using next and back buttons

4.2 Real-Ear Setup

If you are using the FP35 as a portable unit, you can easily convert the internal
sound chamber into a sound field speaker. If you are using the FP35 primarily in
an office or clinical setting, you may wish to set up an external speaker for real-ear
measurements.

4.2.1 General Setup

If not already in place, slide the Velcro mounting sleeves onto the reference
microphone and probe microphone.

When testing, the loudspeaker should be about 12 inches (30 cm) from the surface
of the client’s head (near the temple) and pointing toward the ear to be tested. We
recommend an azimuth angle of 45 degrees (halfway between the client’s nose and
ear). The height of the loudspeaker should be level with, or a little above the ear. See
Figure 4.2.1.

Figure 4.2.1—Real-ear measurement setup

4: Real-Ear Measurements 23

Note: If you want to use a a 90 dB signal during your measurements, the 12 inch
distance is very important. If the client is too far away, a message box will open,
alerting you to move the client closer. Don’t forget to relevel for the client’s new

position.

4.2.2 Internal Speaker Setup

The technique for converting the FP35 analyzer’s internal sound chamber into a
sound field speaker to use for real-ear measurements is described in this section.

Removing the speaker from the FP35 compartment

• Openthesoundchamberlid.Dothisbypressingdownonthemetallatchat

the front of the sound chamber lid.

• Liftthespeakeroutofthecompartment.

Installing the speaker on the metal post

• Locatethemetalpostattherightsideofthecompartment.Removethepost

and place the wide end in the hole at the bottom, right corner of the sound

chamber.

• Placethespeakeronthetaperedendofthepost.Ifthespeakerdoesnotreach

your client’s ear height, you may want to add an optional extension pole that

raises the speaker by an additional 6.5 inches (16.51 cm).

• PositiontheFP35atoneedgeofatable.Thespeakercanberotatedsothatthe

correct angle for testing is easily achieved.

Figure 4.2.2—Internal sound field speaker setup

Replacing the speaker when the test is complete

• Removethespeakerfromthepost.

• Liftthepostoutofitsholeandreturnittotherightsideofthecompartment.

You must first slide one end of the post into the notch toward the front of the

FP35 analyzer. The post will then fit easily onto the ledge.

24 FONIX FP35 Quick Reference Guide

• Makesureallcablesinthecompartmentareputawaysotheywillnot

interfere with replacing the speaker.

• Set the speaker back in the compartment. As you do this, guide the speaker
wire so it stays to the side of the speaker, not underneath it.

4.2.3 External Speaker Setup

If desired, you can use an external speaker to perform your real-ear measurements.
The external speaker can be mounted to a floor stand or to a swing arm. A swing arm
is especially nice because you can move the speaker around the patient when you
switch ears, rather than move your patient around the speaker.

Figure 4.2.3—External sound field speaker setup

To set up your FP35 software to use an external speaker:

1. Press [MENU] from the Opening screen to enter the Default Settings menu.

2. Press [NEXT] to enter the Advanced Default Settings menu.

3. Select SPEAKER under Real-Ear Settings with [5 , 6] keys.

4. Set EXTERNAL with [3, 4]. All real-ear measurements will now be done with
the external speaker.

5. Press [F5] to save the setting as the new default, if desired.

6. Press [EXIT] to return to the Opening screen.

7. Press [F2] to enter Real-Ear Mode again.

4: Real-Ear Measurements 25

Reference
microphone

Wedge-style
earhook

Probe
microphone

Probe

tube

4.2.4 Placing the Probe Tube

To ensure the proper insertion depth of the probe tube into the ear canal, the
following marking procedure is necessary. After some practice, the procedure is easy.

1. Place an unattached probe tube on a flat surface along with the client’s earmold
or shell as shown in Figure 4.2.4A so that the tube rests along the bottom of the
canal part of the earmold, with the tube extending at least 5 mm past the canal
opening.

2. Mark the probe tube with a marking pen where it meets the outside surface of
the earmold.

3. Place the wedge-style earhook on the client’s ear.

4. Attach the reference microphone, facing forward, on the wedge of the earhook,
directly above the ear to be tested.

5. Attach the probe tube to the body of the probe microphone and then attach the
probe microphone to the round Velcro pad on the ear hanger.

6. Insert the probe tube into the client’s ear so that the mark is at the location
where the bottom of the outer surface of the earmold would be. See Figure 4.2B.

Hints: To help keep the probe tube in place, position the tube so that it runs through
the tragal notch, resting against the lower edge of the tragus (Figure 4.2.4B) If
necessary, reposition the body of the probe microphone lower on the Velcro button
of the ear hanger. If desired, use surgical tape to hold the tube in position.

Figure 4.2.4A Figure 4.2.4B Figure 4.2.4C
Mark the probe tube. Place the microphones. Insert the hearing aid.

26 FONIX FP35 Quick Reference Guide

4.2.5 Placing the Sound Field Speaker

The placement of the sound field speaker can have a big influence on the
accuracy and repeatability of your real-ear measurements. Research has shown
that a consistent placement of 45 degrees azimuth to the client produces the
most repeatable testing results. Some clinicians, however, prefer to use the more
traditional 0 degrees azimuth to the client. See Figure 4.2.1 for a diagram of a client
being tested at 45 degrees azimuth.

In both instances, we recommend a distance of 12–15 inches from the speaker to the
client. A larger distance might make the FP35 analyzer unable to produce a 90 dB
SPL signal to the client. A small distance might place the client in an unstable place
in the field of the speaker.

You can specify which azimuth you are using for your real-ear measurements. This
will have an effect on the real-ear targets.

To set the position of the speaker:

1. Press [MENU] in any real-ear measurement screen or in the Audiogram Entry
screen.

2. Use [5 , 6] to select SOUND FIELD.

3. Use [3, 4] to select 0º or 45º.

4. Press [EXIT] to return to the real-ear screen.

Notes:

• Ifyoutookyouraudiometricmeasurementswithasoundeldspeaker,itis

recommended that you use the same azimuth for the real-ear measurements as
you used in the audiometric assessment.

• Thespeakerpositionissetwhenthesoundeldisleveled.Ifyouwantto

change the speaker position after leveling, you must re-level the sound field
speaker for the change to take effect.

• Thelevelingstatuswillreecttheselectedsoundeldspeakerazimuth.By

default, this is set to 45º.

4.2.6 Leveling the Sound Field Speaker

The leveling process measures the sound field at the client’s ear, and accounts for
inconsistencies in the testing environment. It is essential for obtaining accurate real­ear measurements. You must re-level the sound field for every client and for every
ear.

The client must be in the same position for leveling and real-ear testing—you can
use either a 0º azimuth or a 45º azimuth for leveling, as long as it is consistent with
the speaker position used for the real-ear measurements.

4: Real-Ear Measurements 27

Only the larger reference microphone is used during the leveling process. However,
to speed things up and ensure the client is in the same position during leveling and
during the measurement process, it is recommended that you insert the probe tube
in the client’s ear for the leveling process. See Section 4.2.4 for more details.

To level:

1. Place the earhook on the client’s ear.

2. Position the reference microphone on the earhook’s wedge above the client’s ear.
See Figure 4.2.4B.

3. Insert the probe tube into the client’s ear, if desired. (The probe microphone is
not used during the leveling process.)

4. Position the sound field speaker 12–15 inches from the client’s head, at a 0º
or 45º azimuth. (We recommend 45º azimuth in order to produce the most
repeatable results.)

5. Select the azimuth used in the SOUND FIELD setting in the real-ear menu. See
Section 4.2.5 for details.

6. Press [F5]—LEVEL in any of the real-ear measurement screens (not the
audiogram entry screen).

7. Press [START/STOP]. The instrument will now attempt to level the sound field
speaker.

These are the possible leveling status:

• LEVELED0ºorLEVELED45º—Thelevelingprocesswascorrectwithin2dB.

The azimuth used is indicated.

• UNLEVELED—Thelevelingprocesswasincorrectatleast6dB.Youshould

check the speaker, client, and reference microphone position and try to level
the instrument again. No azimuth is indicated for this status.

• 0ºor45º—Astatusshowingonlytheazimuthindicatesthattheleveling

process was correct somewhere between 2 dB and 6 dB. Just as with the
UNLEVELED status, you should check the speaker, client, and reference
microphone position and try to level the instrument again. However, if
repeated attempts fail to reach a leveled status, you can consider this stage
“good enough.” Be aware that measurements when the instrument is in the in­between stage will not be as accurate as measurements taken when the sound
field is leveled.

Note: The environment should be quiet during leveling. Noise can affect the leveling
results, though the FP35 does use measurement methods to minimize the impact of
external noise.

28 FONIX FP35 Quick Reference Guide

4.3 Audiogram Entry Screen—Creating A Target

Creating a target for one or both ears is actually something you can do before the
client even enters the office. The first thing you have to do is enter the audiogram.

4.3.1 Entering the Audiogram Screen

• Ifnecessary,press[F2]fromtheOpeningScreentoentertheRealEarMode.

• TheFP35 will automatically bring you to the real-ear screen you left the last

time you did a real-ear measurement.

• If necessary, use the [NEXT] or [BACK] buttons to reach the Audiogram Entry
Screen.

Figure 4.3.1—Audiogram Entry screen

4.3.2 Entering Audiometric Information & Creating A Target

Use the following instructions to create a non-NAL-NL1 target. See Section 4.3.3 for
NAL-NL1 instructions. The following step-by-step instructions assume that you are
in the Audiogram Entry Screen.

1. Press [MENU] to enter the main local menu, and select the desired EAR, and
ASSESSMENT.

2. Press [BACK] to enter the Target Menu, and select the desired FIT RULE and
AGE.

3. Press [EXIT] to return to the Audiogram Entry Screen.

4: Real-Ear Measurements 29

4. Use [F2] to select HTL. A small arrow cursor will appear in the HTL column of
the data entry box.

5. Use the [5 ,6] keys to move the cursor through the frequencies. Use the [3, 4]
to enter the client’s threshold levels in dB HL at each frequency.

6. If you have measured your client’s uncomfortable levels:

•Press[F2]toselectUCL.

•Usethe[5 ,6] keys to move the cursor through the frequencies. Use [3, 4]

to enter the client’s uncomfortable levels in dB HL at each frequency.

7. Press [F3] to generate a target using your selected fitting rule. If you did not enter
any measured UCLs, predicted UCLs will also be generated.

8. Press [MENU] and change the selected EAR, if desired. Press [EXIT] to exit the
audiogram menu. If you entered the thresholds for the other ear, those thresholds
will automatically be copied to the current ear as a starting point. The UCL and
target values will not be copied.

9. Repeat steps 4-7 for the new ear, if desired.

4.3.3 Creating an NAL-NL1 Target

The NAL-NL1 fitting rule is more adjustable and slightly more complicated than
DSL and the traditional linear fitting rules. In addition to the client’s air conduction
thresholds, it takes into consideration the client’s bone conduction thresholds,
whether the fitting is binaural or monaural, the number of channels of the hearing
aid, and the type of limiting the aid has. The steps to creating an NAL-NL1 target are
very similar to creating a DSL or a linear target – NAL-NL1 just requires a few more
menu selections.

To create an NAL-NL1 target:

1. Press [MENU] in the Audiogram Entry screen and use the arrow keys to select
the following:

• EAR: Current ear

• ASSESSMENT: Type of transducer used in creating the audiogram

2. Press [BACK] to enter the Target menu. Use the arrow keys to select the
following:

•FITRULE:NAL-NL1

•AGE:Ageoftheclient

•COMPRESSION:Thewidebandcompressionthresholdoftheaid

•CHANNELS:Thenumberofchannelsoftheaid

•AIDLIMITING:Thetypeoflimitingthehearingaidhas

• FIT TYPE: Unilateral or bilateral

3. Press [EXIT] to return to the Audiogram Entry screen.

30 FONIX FP35 Quick Reference Guide

4. Press [F2] until HTL is selected. A small arrow cursor will appear in the HTL
column of the data entry box.

5. Use the [5 ,6] keys to move the cursor through the frequencies. Use the [3, 4]
to enter the client’s threshold levels in dB HL at each frequency.

6. (Optional) Press [F2] to select UCL, and use the arrow keys to enter the client’s
UCL values in the same manner as you entered the HTL values.

7. (Optional) Press [F2] and select BONE in order to enter the client’s bone
conduction thresholds. Use the arrow keys to enter the bone values in the same
manner as you entered the HTL values.

8. Press [F3] to generate the NAL-NL1 target. If you did not enter any measured
UCL values, predicted UCLs will also be generated.

9. (Optional) If you selected a FIT TYPE of “bilateral” in Step 2, you need to enter
audiometric data from both ears.

10. Press [MENU] to enter the menu.

11. Change the EAR by using the arrow keys.

12. Press [EXIT] to return to the Audiogram Entry screen. The threshold values for
the first ear will be displayed on the screen as a starting point for the entry of the
new audiogram.

13. Repeat Steps 4-8 to enter the audiogram for the new ear.

4.3.4 Measuring the Real-Ear to Coupler Difference

The real-ear to coupler difference (RECD) is the acoustical difference between
the response of an insert earphone in the ear versus in a 2-cc coupler. It involves
two measurements: a coupler measurement, and a real-ear measurement. Both
measurements are performed with an insert earphone.

The coupler part of the RECD is performed when you “calibrate” the insert
earphone used in the measurement. When this calibration is performed, the coupler
measurement is saved into the FP35 analyzer’s permanent memory. See Appendix C
of the Operator’s Manual for instructions on performing the calibration of the insert
earphone.

4.3.4.1 Analyzer Setup for RECD

This section describes how to set up the analyzer to perform the real-ear portion of
the RECD.

1. Enter the Audiogram Entry Screen (See Section 4.3.1).

2. Press [MENU].

3. Select desired EAR, using [3] if necessary.

4. Select ASSESSMENT with [5 , 6] keys.

5. Press [3, 4] to select INS. EAR.

6. Press [EXIT] to return to Audiogram Entry Screen.

4: Real-Ear Measurements 31

7. Press [F2] repeatedly until RECD (or REDD) is selected. You will see an
additional column of average RECD information for the selected age appear on
the screen.

8. Make sure that SHOW RECD is displayed above [F5]. If it isn’t, press [F5] to
toggle the display.

9. Look at the bottom right corner of the LCD screen. If you see the message
“Earphone not calibrated,” you will need to follow the instructions found in
Appendix C of the Operator’s Manual for calibrating the insert earphones. See
Figure 4.3.4.1.

10. Press [F3] to select MEASURE RECD.

11. Plug the insert earphone into the “earphone” jack in the back of the FP35.

Figure 4.3.4.1— This screen indicates that the coupler part of the RECD needs to be taken.

4.3.4.2 Client Setup for RECD

This section describes how to set up the client for the real-ear portion of the RECD
measurement.

1. Insert the probe microphone into your client’s ear. See Figure 4.3.4.2A.

2. Insert custom earmold or foam eartip coupled to the insert earphone into your
client’s ear. See Figure 4.3.4.2B.

32 FONIX FP35 Quick Reference Guide

Probe mic

Probe mic

3A

INSERT

EARPHONE

Foam eartip

Figure 4.3.4.2A—Insert probe microphone Figure 4.3.4.2B— Insert foam eartip
connected to insert microphone

4.3.4.3 Taking the RECD Measurement

If you’ve performed the steps described in Sections 4.3.4.1 and 4.3.4.2, you just have
to press [START/STOP] to take the RECD measurement. Results will be displayed in
graphical format in dB GAIN as well as numerical format in the data table.

To erase the measured RECD, press [F4] and [START/STOP].

4.4 Insertion Gain Testing

An insertion gain test measures how much gain the hearing aid is providing over the
client’s unaided response. This section assumes you have already generated a target
curve (see Section 4.3.2 and 4.3.3) and are ready to test.

The Unaided & Aided Response screen and the Insertion Gain Screen are two parts
of the same insertion gain method of fitting hearing aids. The Unaided & Aided
Response Screen lets you measure and view aided gain measurements of the
hearing aid. See Figure 4.4A. The Insertion Gain screen displays the insertion gain
target and lets you measure and view insertion gain measurements of the hearing
aid. See Figure 4.4B. We divided insertion gain into two screens in order to clearly
distinguish between the aided gain and insertion gain curves.

Insertion gain is the difference between the client’s unaided response and his/her
aided response. In other words, insertion gain is the actual gain that the aid is
producing. Aided gain, in contrast, is the gain the aid is producing plus the natural
gain of the ear.

4: Real-Ear Measurements 33

Figure 4.4A—Real Ear Aided & Unaided screen

Figure 4.4B—Real-Ear Insertion Gain screen

34 FONIX FP35 Quick Reference Guide

4.4.1 Measuring the Unaided Response

The first step in taking an insertion gain measurement is to measure the unaided
response. You can do this from either the Unaided & Aided Response Screen or the
Insertion Gain Screen.

If you are using the average unaided response, skip to the next section.

1. Place the probe tube in your client’s ear as described in Section 4.2.4. Level the
sound field speaker. See Section 4.2.6.

2. Press [F4] to select the signal type. Use COMP if you have the Composite Option.
If not, use NORM.

3. Press [F2] to select CUSTOM UNAIDED. If AVG UNAIDED appears, press
[MENU] and use the arrow keys to change the UNAIDED selection to CUSTOM.
Press [EXIT] to close the local menu.

4. Use the [5 , 6] keys to adjust the source amplitude to 65 or 70 dB SPL.

5. Have the client sit still in the same position they were in during leveling, and
press [START/STOP] to begin measuring the unaided response. If you are using
the composite signal, press [START/STOP] when the measurement stabilizes.

6. The real-ear unaided response (REUR) will be displayed on the graph as a dotted
line marked with the letter N.

Note: To display the average unaided measurement, set UNAIDED to AVERAGE in
the menu. Then select AVG UNAIDED with [F2] and turn ON its display with [F3].

Figure 4.4.1—Unaided response

4: Real-Ear Measurements 35

4.4.2 Measuring the Aided Response

The second step in an insertion gain measurement is the aided response.

If you would like to view the measurement as an insertion gain curve and compare
it to an insertion gain target, take this measurement from the Insertion Gain Screen.
If you would prefer to view the aided gain, take this measurement from the Unaided
& Aided Response Screen. Move between the two screens by using the [NEXT] and
[BACK] keys while in Real-ear mode.

Whenever you take a measurement in one of these screens, it will automatically be
converted and placed into the other screen.

To take an aided measurement:

1. Place the aid into the client’s ear taking care not to drag the probe tube further
into the ear canal. Once the aid is in the ear, the red mark on the probe tube
should be at the same position it was for the unaided test. (See Figure 4.2.4C.)

2. Have the client set the aid’s gain control to the normal use level.

3. Press [F4] to select the source type. DIG SPCH is recommended if you have the
Composite/Digital Speech Option. Otherwise, use FAST.

4. Use the [5 , 6] buttons to adjust the source amplitude to the desired level,
usually the same level used for the unaided measurement.

5. Instruct the client to resume the position they were in for leveling and testing.
Tell them to sit very still while the signal is on.

6. Press [START/STOP] to introduce the signal. The aided response will appear on
the graph as a thin line labeled with a curve number. See Figure 4.4.2.

Note: If you are using the COMP, DIG SPCH, or FAST signal, you can change the

source amplitude during testing to see how the aid responds to such changes.

7. Press [START/STOP] to end the measurement if you are using the COMP, DIG
SPCH, or FAST signal.

8. If desired, press [F2] to select a another curve number and repeat steps 3-7.

36 FONIX FP35 Quick Reference Guide

Figure 4.4.2 —Unaided and aided response

4.4.3 Testing Automatically

The FP35 analyzer has the capability of performing automatic real-ear aided
measurements. This feature automatically tests the three aided measurements
automatically without needing user intervention between measurements. Auto Test
always measured AIDED 1, 2, and 3, in that order.

To enable auto test:

1. Press [MENU] in the real-ear measurement screen.

2. Use [∨, ∧] to select AUTO TEST and set it to ON.

3. Press [EXIT] to close the menu.

4. Press [START/STOP]. The analyzer will automatically test AIDED 1, AIDED 2,
and AIDED 3.

The Auto Test feature can be defaulted to on. See Section 1.3 for details

4.4.4 Testing Directional Hearing Aids

The Insertion Gain screen is a good place to perform a directionality test for
directional hearing aids. In an insertion gain measurement, the unaided curve is
subtracted from the aided curve in order to arrive at the insertion gain curve. You
can use this functionality in order to find out how much advantage the directional
microphones of the hearing aid are providing.

4: Real-Ear Measurements 37

To test directionality:

1. Place the probe tube in your client’s ear as described in Section 4.2.4, and level
the sound field speaker as described in Section 4.2.6. Although we usually
recommend a 45º azimuth for real-ear measurements, for this measurement you
should use a 0º azimuth, with the sound field speaker directly in front of the
patient.

2. Place the hearing aid in your client’s ear, making sure not to move the probe
tube.

3. Enter the Unaided & Aided Response screen. Use the [NEXT] and [BACK] keys if
necessary.

4. Press [MENU] to enter the real-ear menu. Make sure that CUSTOM is selected for
UNAIDED. Use the arrow keys to make the selection, if necessary. Press [EXIT] to
return to the real-ear measurement screen.

5. Press [F1] and [START/STOP] to clear all existing curves, if necessary.

6. Use [F2] to select AIDED #1.

7. Use [F4] to select the signal type. DIG SPCH is recommended if you have the
Composite/Digital Speech Option. Otherwise, use FAST.

8. Use [5 , 6] to select a signal source of 65 dB SPL.

9. Press [START/STOP] to take the measurement. If you’re using a FAST, COMP
or DIG SPCH signal, press [START/STOP] again to stop the signal once the
measurement has stabilized. This curve will be the “forward” measurement.

10. Turn your client around so that the back of his head is facing the speaker. See
Figure 4.4.4A. Alternately, if you are using an external speaker on a swing arm,
you can swing the speaker around the client.

11. Use [F2] to select CUSTOM UNAIDED. Although this is an aided measurement,
the “unaided” measurement slot will give you a nice directional subtraction
curve when the second measurement is completed.

12. Use [F4] to select the signal type used in the “forward” measurement.

13. Use [5 , 6] to select a signal source of 65 dB SPL.

14. Press [START/STOP] to take the measurement. If you’re using a FAST, COMP
or DIG SPCH signal, press [START/STOP] again to stop the signal once the
measurement has stabilized. This curve is the “reverse” measurement. See Figure

4.4.4B.

15. Press [NEXT] to enter the Insertion Gain screen. The displayed measurement
curve is the difference between the “forward” and the “reverse” measurements,
or the amplification advantage provided by the directional microphones of the
hearing aid. See Figure 4.4.4C.

38 FONIX FP35 Quick Reference Guide

Figure 4.4.4A—“Reverse” directional aid setup

Figure 4.4.4B—“Forward” and “reverse” directional aid measurements in the real-ear
unaided & unaided screen

4: Real-Ear Measurements 39

Figure 4.4.4C—Amount of amplification advantage provided by the directional microphones

4.5 Testing in the SPL Screen

The SPL screen permits the user to view all the major components of a client’s
hearing loss and hearing aid fitting on one screen in dB SPL. The hearing thresholds
and uncomfortable loudness levels, which are generally measured in HL, are
converted to SPL. The insertion gain target is also converted to SPL. You can
measure and display the unaided response and three aided responses, in SPL, at
three different source amplitude levels. Having all this information in a common
format provides a convenient way to view the hearing loss and the amplification
provided by the hearing aid without the confusion of different frames of reference.

The factory default amplitudes used in this program are generally 50, 65 and 90 dB.
(When DSL is the selected fitting rule, these default levels will vary.) The user may
choose other amplitude levels while conducting the tests. The idea is to make sure
that:

•Softsoundsareaudible(AIDED1).

•Moderatesoundsarecomfortable(AIDED2).

•Loudsoundsdonotexceedtheuser’suncomfortableloudnesslevel(AIDED3).

This technique is especially appropriate for non-linear hearing aids.

40 FONIX FP35 Quick Reference Guide

4.5.1 Viewing the SPL Display

The information on the SPL screen is similar to the information in the other real­ear measurement screens. However, in addition to the measurement curves and the
SPL-converted target, the SPL Screen also displays SPL-converted thresholds and
uncomfortable levels, allowing you to directly compare the measurement curves to
the audiometric information.

X denotes left thresholds
O denotes right thresholds

denotes the target

*

U denotes the uncomfortable levels.

Figure 4.5.1—SPL display

4.5.2 Running an SPL Test

This section assumes you have already entered the client’s audiometric data in the
Audiogram Entry Screen, and that you have generated a target. See Section 4.3.3 and

4.3.4 for more details.

1. Place the probe tube into the client’s ear following the instructions provided in
Section 4.2.4.

2. Insert the aid into the client’s ear, being careful not to drag the probe tube farther
into the ear canal (See Figure 4.2.4C). Do not turn the aid on.

3. Instruct the client to remain still when the signal is on.

4. Press [F5] and [START/STOP] to level.

5. Have the client turn the aid on and set the gain control to the normal use level.

4: Real-Ear Measurements 41

6. Use [F2] to select AIDED 1.

7. Use [F4] to select the source type for AIDED 1, and use the [5 , 6] buttons to set
the source amplitude

8. Have the client resume the position they were in during leveling, and remind
him to stay still while the signal is on.

9. Press [START/STOP] to test. If you are using the COMP, DIG SPCH, or FAST
signal source, you will need to press [START/STOP] again to stop the signal.

10. Repeat steps 6 through 9 for AIDED 2 and AIDED 3. See Figure 4.5.2.

In general, AIDED 1 is tested at low levels (50 dB SPL) to make sure soft sounds are
above the patient’s threshold values. AIDED 2 is tested at medium levels (65-70 dB
SPL) to make sure that the aid meets the target. AIDED 3 is tested at loud levels (90
dB SPL) to make sure that loud sounds are beneath the patient’s UCLs.

Figure 4.5.2—Real-Ear SPL screen with measurements

4.5.3 Testing Automatically

The FP35 analyzer has the capability of performing automatic real-ear aided
measurements. This feature automatically tests the three aided measurements
automatically without needing user intervention between measurements. Auto Test
always measured AIDED 1, 2, and 3, in that order.

To enable auto test:

1. Press [MENU] in the real-ear measurement screen.

2. Use [∨, ∧] to select AUTO TEST and set it to ON.

42 FONIX FP35 Quick Reference Guide

3. Press [EXIT] to close the menu.

4. Press [START/STOP]. The analyzer will automatically test AIDED 1, AIDED 2,
and AIDED 3.

The Auto Test feature can be defaulted to on. See Section 1.3 for details

4.6 Live Speech Testing

In the Spectrum Analysis mode, available with the Composite/Digital Speech Option,
you can use the external signal of your choice with your real-ear measurements,
including sounds from a CD player, the patient’s own voice, or the voice of a spouse
or family member. Several different methods of using external signal in your real-ear
measurements are described in this section.

When you use live speech in the real-ear SPL screen, you can compare the hearing
aid’s response to the actual speech to the patient’s threshold and uncomfortable
levels. This can be a great counseling tool for your patient.

4.6.1 Using Speech as a Test Signal

Live speech can be a very effective tool in showing the aid’s frequency response in
a real-world environment. It is especially useful if you have the spouse or family
member of the client in the testing room and can use his/her voice as the test signal.
This makes a great counseling tool for both the client and his family member in
showing them how close they need to be to each other in order for the hearing aid to
work effectively.

The live speech measurement can be taken in any measurement screen, but this
section will focus on measurements in the Real-Ear SPL screen.

To set up for live speech mapping:

1. Follow the instructions in Section 4.2 to set up the client and hearing aid for
real-ear measurements. The sound field speaker does not need to be leveled for
live speech testing.

2. Insert the patient’s hearing aid carefully and turn it on with the volume control
at the normal user setting.

3. Follow the instructions in Section 4.3 to create a real-ear target, if desired.

4. Enter the Real-Ear SPL screen by using [NEXT] from the Audiogram Entry
screen.

5. Use [F4] to select COMP.

6. Press [6] repeatedly until the SOURCE is turned OFF. This is displayed in the
source box on the display above the F3 key.

To start measuring:

1. Press [START/STOP] to start the measurement.

4: Real-Ear Measurements 43

2. Instruct your patient’s spouse speak to the client about 6 feet away (2 meters).
It helps to have something for them to read. The screen will display the aid’s
response to this speech and how it relates to the speech banana. A second curve
composed of small diamonds will also be displayed. This shows the average
response to the live signal. You can compare this curve to the target. See Figure

4.6.1.

3. Press [START/STOP] to stop the measurement. Show your patient and his spouse
how the hearing aid amplified the speech.

4. Press [F2] to select AIDED 2, and repeat steps 5-6 in the section above. Press
[START/STOP] to start a second measurement.

5. Instruct your patient’s spouse to stand 3 feet away (1 meter) and speak again.

6. Press [START/STOP] to stop the measurement. Show your patient and his spouse
how the distance improved the gain of the frequency response.

7. Experiment in this manner with different distances. This will help demonstrate
how close your patient and his spouse need to be to each other to maximum
speech intelligibility.

Figure 4.6.1—Visible Speech Testing

4.6.2 Measuring the occlusion effect

If you have the Composite/Digital Speech Option, you can use the Aided & Unaided
screen in order to measure the “occlusion effect” of a hearing aid. By analyzing the
spectrum of your patient’s own voice, you can judge whether the occlusion effect
will make the hearing aid uncomfortable, and you can measure an improvement
(lessening) of the occlusion effect after adjusting the vent opening.

44 FONIX FP35 Quick Reference Guide

To set up for measuring the occlusion effect:

1. Enter the Unaided & Aided screen. To do this, press [F2] from the Opening
screen and use [NEXT] or [BACK] until the Unaided & Aided screen appears.

2. Follow the instructions in Section 4.2.4 to insert the probe tube into your
patient’s ear. There is no need to level the sound field speaker when measuring
the occlusion effect.

3. Insert the patient’s hearing aid, becing careful not to move the probe tube. The
hearing aid can be turned on or off.

4. Use [F2] to select UNAIDED. If AVG UNAIDED shows up above F2, press
[MENU] and use the arrow keys to change UNAIDED to CUSTOM. Press [EXIT]
to close the menu.

5. Use [F4] to select COMP.

6. Press [6] repeatedly until the SOURCE is turned OFF. This is displayed in the
source box on the display above the F3 key.

7. Press [MENU] to open the local menu, and use the arrow keys to change NOISE
RED (COMP) to 16X. This will increase the amount of averaging the analyzer
does when the measurements are performed. Press [EXIT] to close the local
menu.

To measure the ocxclusion effect:

1. Press [START/STOP] to start the measurement.

2. Instruct your client to sustain the vowel sound “eee.”

3. Press [START/STOP] while the “eee” is still sounding and the curve has
stabilized. The patient can now stop vocalizing.

4. Look at the gain in the low frequencies. If it seems high, you may consider
adjusting the vent to a more open condition in order to prevent occlusion-effect
discomfort.

5. Press [F2] to select AIDED 1. Make sure COMP is the selected source type
above F4, and the SOURCE is OFF. Use [F4] and [6] to make these selections, if
necessary.

6. Press [START/STOP] to start a second measurement.

7. Ask your patient to sustain an “eee” sound again. Press [START/STOP] during
the vocalization when the measurement has stabilized. (You can then tell your
patient to stop.)

8. Compare AIDED 1 to the “UNAIDED” measurement to see how your vent
adjustments have changed the response of the hearing aid.

9. Press [NEXT] to view the Insertion Gain screen. This will show you the actual
difference that your adjustments made—the first measurement is subtracted
from the second measurement.

Chapter 5 45

Coupler

Multicurve

Coupler

Target

Coupler

EarSim

2-CC Targets

In the 2-cc target screens, you can measure hearing aids using a coupler in a sound
chamber and compare them to a target. This type of testing is especially useful
when fitting a patient who is unable to sit still for a real-ear measurement, such as
an infant or a young child. There are two 2-cc target screens available: the Coupler
Target screen, which converts real-ear targets into coupler targets, and the Coupler
EarSim screen, which converts coupler measurements into simulated real-ear
measurements. The Real-ear Option is required to access these screens.

In the Coupler Target screen, real-ear targets are converted into coupler targets so
that you can compare them to coupler measurements. Targets and measurements can
be displayed in either dB SPL or dB GAIN.

In the Coupler EarSim screen, the opposite approach is used, and actual real-ear
targets are displayed. When coupler measurements are taken, the response curves
are converted, using average or measured RECD transforms, into simulated real­ear measurements, which can then be directly compared to the displayed real-ear
targets. Two displays are available: Insertion Gain and SPL. When the SPL display is
selected, the patient’s HTL and UCL values are also displayed on the screen. These
HTL and UCL values are identical to the ones that would be displayed in the real-ear
SPL screen.

The Coupler Multicurve (described in Chapter 2), Coupler Target, and Coupler
EarSim screens are all connected to each other by the [NEXT] and [BACK] keys,
similar to the way that the real-ear screens are connected to each other. Any
measurements taken in one screen are automatically converted to the other screens,
minimizing your measurement time.

46 FONIX FP35 Quick Reference Guide

5.1 Target Creation

In order to create a target for use in the Coupler Target or Coupler EarSim screen, you
must enter the patient’s threshold values in the Audiogram Entry screen, just as you
would if you were creating a real-ear target.

To create a target in the Target Coupler screen:

1. Enter the Audiogram Entry screen by pressing [F2] from the Opening screen and
using the [NEXT] and [BACK] keys if necessary.

2. Follow the instructions found in Section 4.3 to enter the patient’s audiogram and
to create a real-ear target.

3. Follow the instructions found in Section 4.3.4, if desired, to measure the
patient’s RECD.

4. Press [EXIT] to return to the Opening screen.

5. Press [F3] to enter one of the coupler multicurve screens. If the screen is labeled
COUPLER MULTICURVE (the label is found on top of the large graph), press
[NEXT] to enter the Target Coupler screen.

6. Press [MENU] and [BACK] to enter the Target menu. Set the AID TYPE, FIT
RULE, and AGE in this menu using the arrow keys. If you are creating an NAL­NL1 coupler target, you will also have to set COMPRESSION, CHANNELS, AID
LIMITING, FIT TYPE, TUBING, and VENT. See Section 4.3.3 for details.

7. Press [EXIT] to return to the measurement screen. You are now ready to perform
the coupler measurements.

5.2 Coupler Target

Press [NEXT] from the Coupler Multicurve screen or [BACK] from the Coupler
EarSim screen to enter the Coupler Target screen.

In the Coupler Target screen, the real-ear target is converted into a coupler target
displayed in either dB GAIN or dB SPL. Coupler measurement can be performed and
compared directly to the target. The only major difference between this screen and
the basic Coupler Multicurve screen (described in Chapter 2), is the addiition of the
coupler target. See Figure 5.2.

To get the most accurate real-ear to coupler target conversions, measure the patient’s
unaided response in one of the real-ear measurement screens (Section 4.4.1) and
the RECD in the Audiogram Entry screen (Section 4.3.4). When these measurements
are not taken, average values, corrected for the age of the patient, are substituted
automatically.

See Section 2.2 for instructions on how to perform measurements in the Coupler
Target screen—the operation of the Coupler Target screen is identical to the operation
of the Coupler Multicurve screen.

5: 2-cc Targets 47

Figure 5.2—Coupler Target screen.

5.3 Coupler EarSim

Press [NEXT] from the Coupler Target screen or [BACK] from the Coupler Multicurve
screen to enter the Coupler EarSim screen.

In the Coupler EarSim screen, the actual real-ear target prescribed for the patient
is displayed in either dB IG (insertion gain) or dB SPL. When the Coupler EarSim
display is set to dB SPL, the patient’s threshold and uncomfortable values are
also displayed. Any coupler measurement made in this screen is converted into
simulated real-ear measurements that are directly comparable to the displayed real­ear target.

To get the most accurate real-ear to coupler target conversions, measure the patient’s
unaided response in one of the real-ear measurement screens (Section 4.4.1). The
measured REUR will be used to convert the coupler measurements into simulated
real-ear measurements. See Section 4.4.1 for instructions on performing the REUR
measurement.

In the SPL display (Figure 5.3), the patient’s audiometric data (HTL and UCL values)
are converted from dB HL to dB SPL and displayed on the screen. To get the most
accurage HL to SPL conversion (and the most accurage real-ear target), measure the
patient’s RECD in the Audiogram Entry screen. See Section 4.3.4 for details.

When the REUR and RECD are not measured, the FP35 substitutes average data
to calculate the real-ear target and the coupler measurement conversions. These
averages are sensitive to the selected age of the patient.

48 FONIX FP35 Quick Reference Guide

Figure 5.3—Coupler EarSim screen.

See Section 2.2 for instructions on how to perform measurements in the Coupler
EarSim screen—the operation of the Coupler EarSim screen is identical to the
operation of the Coupler Multicurve screen.

FONIX FP35 Quick Reference Guide 49

Index

A

Aided Response 35
ANSI 15

ANSI 03 15
ANSI 96 15

Arrow keys 2
Audiogram Entry 21
Audiogram Entry Screen 27
Auto Test 36, 41

B

Back 2

C

COMPOSITE 9
Coupler EarSim 47
Coupler Multicurve 7
Coupler Target 46

D

default selections 4
digital aid 10
Digital Hearing Aids 18
Directional Hearing Aids 36
DSL 29
DSP SPCH 9

E

Exit 2
external printer 6
External Speaker 24

F

FAST 8
frequency response mea-

surements 8
front panel 1
Function keys 1, 2

H

Harmonic distortion 11
Help 1, 2

I

IEC 18
Insertion Gain 21, 32
Insertion Gain Screen 32
Intermodulation distortion

12

L

Leveling 7

sound field speaker 26

Live speech 41
local menu 3

M

Menu 1, 3
metal post 23

N

NAL-NL1 29
Navigation 21
navigation 2
Next 2
NORMAL 8

O

occlusion effect 43
Operate 1

P

post 23
Print 1
printing 6
Probe Tube 24

R

Real-Ear SPL 21
Real-Ear Unaided & Aided

21
RECD 30
Reset 1, 2

S

Settings 4
Setup

real-ear 22

SHORT 8
simulated real-ear 47
Sound Field Speaker 25
sound field speaker 23
Spectrum Analysis mode

41
SPL screen 39
SPL Test 40
Start/Stop 2

T

Target 27, 28, 46
target 46
thermal printer 6

U

Unaided & Aided Response

Screen 32
Unaided Response 34