FONIX® FP35 Hearing Aid Analyzer Operator’s Manual Ver. 4.00 Ver. 4.00: 5/12/08 ©2008 Frye Electronics, Inc.
Table of Contents iii Contents Chapter 1: An Overview of the FP35 1.1 A Guide to Using this Manual . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.2 Layout, Controls, & Safety . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 1.2 .1 Lamps and LCD . . . . . . . . . . . . . . . . . . . . . . . . .
iv FONIX FP35 Hearing Aid Analyzer 2.5.1.1 Delay Settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 2.5.1.2 Harmonic Distortion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 2.5.1.3 Noise Reduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Table of Contents 3.6 CIC Option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 3.7 OES Option . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74 3.8 Advanced Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
vi 5.3 5.4 5.5 5.6 5.7 5.8 FONIX FP35 Hearing Aid Analyzer 5.2.5 Placing the Sound Field Speaker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116 5.2.6 Leveling the Sound Field Speaker . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116 5.2.7 Testing Digital Aids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Table of Contents vii 5.9 CROS, and BICROS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162 5.9.1 Measuring the Head-Baffle Effect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162 5.9.2. Measuring the Overcoming of the Head-Baffle Effect . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Chapter 1 1 An Overview of the FP35 Welcome to the FONIX FP35 analyzer! The FONIX FP35 provides quick, accurate information about how well a hearing aid works. It uses a graphical display or numerical table to show how much amplification the aid provides, which frequencies it amplifies, and how much distortion is creates. The FP35 hearing aid analyzer is a lightweight instrument notable for its ease of use.
2 FONIX FP35 Hearing Aid Analyzer 1.1 A Guide to Using this Manual The FP35 is easy to use. You can begin testing right away, and, if you do happen to get stuck, the pop-up help menus will guide you through what to do next. In addition, this manual contains detailed instructions and information about all the different testing capabilities and options that the FP35 gives you. The FP35 Operator’s Manual follows a logical, sequential order and is meant to be read in order.
3 An Overview of the FP35 Figure 1.2.1—FP35 front panel 1.2.2 Front panel layout The front panel of the FP35 analyzer consists of 8 function keys, 4 arrow keys, and 9 other keys with varying operations. Together, these keys are used to control all the operations of the FP35 analyzer. Function Keys: There are five “function keys” located just below the FP35’s front panel, labeled [F1] through [F5]. The function of these keys change from screen to screen, according to the need of the screen.
4 FONIX FP35 Hearing Aid Analyzer [NEXT] [BACK] Moves back and forth between screens that are in a sequences. Examples include menus and the real-ear measurement screens. [∧, ∨] Moves the cursor up and down in a menu screen and in the Audiogram Entry screen. Adjusts the level of the source amplitude in a measurement screen.
5 An Overview of the FP35 Video Connects to an external monitor (optional). Earphone Connects an insert earphone to the FP35 in order to perform RECD or audiometric measurements. It can also be used to connect a Telewand or telecoil board for telecoil measurements. Speaker Connects an external sound field speaker or external sound chamber to the FP35 analyzer. Can also be used to connect an external telecoil board or Telewand (new rear panel only) Contrast Changes the contrast of the LCD display.
6 FONIX FP35 Hearing Aid Analyzer 1.3 Accessories 1.3.1 Standard Accessories HA-1 2-cc Coupler Dimensions per requirements of ANSI S3.7 for testing in-the-ear hearing aids HA-2 2-cc Coupler Dimensions per requirements of ANSI S3.7 for testing ear level, eyeglass and body aids Ear-Level (BTE) Adapter Snaps into the 1/4 in (6.35 mm) diameter cavity in the HA-2 2-cc coupler. Equipped with a 0.6 in (15 mm) length of 0.076 in (1.93 mm) ID tubing, the adapter allows ANSI S3.
7 An Overview of the FP35 Coupler-only Microphone Shipped with all units that do not have the Real-Ear Option. See optional accessories list for a sound chamber-only two microphone setup. Microphone Adapter 14 mm to 1-inch diameter microphone size. Couples the microphone to a calibrator. Other Standard Accessories • Standard External Power Supply • Roll of Paper • Operator’s Manual • Fun-Tak • RS232 Cable 1.3.
8 FONIX FP35 Hearing Aid Analyzer Wedge Style Earhook Standard size. Holds probe and reference microphones during real-ear testing. Improved design eliminates need for Velcro headband. Other Real-Ear Option Accessories: • Probe Calibration Adapter—Provides a means of coupling the probe microphone to a calibrator. • Calibration Clip—Used to couple the probe and reference microphones together for calibration purposes.
An Overview of the FP35 9 External Monitor Option Used for the external display of the FP35 analyzer. Requires the external monitor option. Quest QC-10 Sound Level Calibrator For calibration of microphone amplifier; operates at 1000 Hz at a level of 114 dB SPL. Swing Arm Speaker Gives you a wide range of speaker-position angles and heights to work with when testing in real ear.
10 FONIX FP35 Hearing Aid Analyzer Child Size Wedge Style Earhook Holds probe and reference microphones during real-ear testing. Infant Headband Package Used for performing real-ear measurements on infants and small children. Includes infant, child, and adult headbands, six flexible ear hooks, and two sets of “animal ears.” Single Insert Earphone (RECD) Consists of one ER3A earphone with a phono plug, a 72 inch cable, an assortment of ear tips, a calibration certificate, and a lapel clip.
An Overview of the FP35 11 Dual Insert Earphones Y Cable 3.5 mm stereo phone plug to 1/4” phone jack. Connects dual insert earphone to FP35. Included with the Dual Insert Earphone Option. Two Microphone System This two microphone setup can be ordered for sound chamber-only FP35 analyzers in order to enable testing with a reference microphone. Earphone Calibration Adapter Connects the Insert Earphone to the HA2 coupler. Included with the Audiometer Option.
12 FONIX FP35 Hearing Aid Analyzer Telewand Allows the measurement of telecoil per ANSI S3.22-1996 and ANSI S3.22-2003. Also allows real-ear telecoil measurements. Telecoil Board Allows the measurement of telecoil in sound chamber measurements. External Sound Chamber Connect the FP35 analyzer to an external sound chamber for better sound isolation and positioning. Sound chamber models 6040 and 6050 can be used. 1.
An Overview of the FP35 13 The composite signal is especially important for the measurement of automatic gain control and signal processing hearing aids. The digital speech signal is a randomly interrupted composite signal used for testing high-end digital aids with “noise-reduction” or “speech enhancement” features. See Appendix F for details. Real-Ear Option You can order the FP35 with the Real-Ear Option so that you can do tests on the hearing aid while it is in the client’s ear.
14 FONIX FP35 Hearing Aid Analyzer Note: The FP35 is fully upgradeable. These options can be added to an existing unit. ISI An automated test sequence conforming to the Indian ISI IS-10775-1984 standard. 1.5 Setup Unpack and locate all of the accessories. If you ordered the briefcase as an optional accessory, the FP35 and its accessories will be packed inside. Otherwise, the instrument and its accessories will be packed in boxes.
An Overview of the FP35 15 b. The equipment complies with relevant IEC and ISO safety standards and is supplied from a medical grade isolation transformer. c. The equipment complies with relevant IEC and ISO safety standards and is kept at least 1.5 meters from the patient. The allowable leakage currents of IEC 60601-1-1 must not be exceeded. IEC 60601-1-1 should be consulted when assembling such a system. Electromagnetic compatibility The FP35 complies with IEC 60601-1-2.
16 FONIX FP35 Hearing Aid Analyzer Frye Electronics, Inc. is a Registered Firm of British Standards Institution, and we conform to the ISO 13485 standard. Safety Classification for IEC 60601-1 Protection against electric shock—Class 1, Type B Protection against harmful ingress of water—Ordinary Mode of operation—Continuous Warning: This equipment is not suitable for use in the presence of a flammable anaesthetic mixture with air or with oxygen or nitrous oxide.
An Overview of the FP35 17 first, since many problems can be fixed without returning the whole unit. If something must be returned, a return authorization number (RMA) will be issued to be attached to all returned materials. When contacting the factory, please have the serial number of your instrument on hand. Look for this number on the rear panel of the instrument. It will also be helpful for you to be able to tell us the software version installed on your machine.
Chapter 2 19 General Operation This chapter describes the general operation of the FP35 analyzer, including basic operation of the keys, screen navigation, default settings, source types, and printing. 2.1 Operation of Keys The general operation of the various keys on the FP35 analyzer is described in this section. This includes a description of the function keys, the arrow keys, and the Menu, Help, Reset, Exit, Level, Feed, Print, Stop, and Start keys. 2.1.
20 FONIX FP35 Hearing Aid Analyzer Note: To exit from any screen, press the [EXIT] key. OPENING SCREEN F2 F3 F4/F5 Audiogram Entry Coupler Multicurve ANSI Real-Ear SPL Coupler Target IEC Unaided & Aided Coupler EarSim JIS Insertion Gain ISI Figure 2.1.1A—Flowchart of the FP35 screens Toggle Pressing a function key in a measurement screen will usually toggle a selection. For instance, pressing [F2] in the Coupler Multicurve screen will toggle through the various curves.
General Operation 21 Action Sometimes function keys perform an action. For instance, in most measurement screens, [F5] levels the sound chamber. By looking at the label of the function key, you should be able to determine the action of the function key. Figure 2.1.1B—Function key balloon menu 2.1.2 Using the Local Menus Each screen contains a local menu that is displayed when you press the [MENU] key.The local menu, overlaid on the current screen, contains only settings that pertain to that screen.
22 FONIX FP35 Hearing Aid Analyzer There are three different types of menu items: local variables that are only active within the current screen, global variables that are available in all screens that use it, and resetable variables that change to a default value when [RESET] is pressed or the unit is first turned on. Resetable variables can be local or global. Most global and resetable variables are available in the Default Settings menu. Local variables are not available in the Default Settings screen.
General Operation 23 Changing a global variable will change its value in all screens where it is available, including the Default Settings menu. 2.1.3 Using the Help Menus Each screen of the FP35 analyzer contains a pop-up help feature to aid you if you ever get stuck. If you find yourself uncertain of your next step, press the [HELP] key. A pop-up window (Figure 2.1.3) will appear that lists the active keys and explains what they will do from your current screen. Figure 2.1.3—Pop-up Help Screen 2.1.
24 FONIX FP35 Hearing Aid Analyzer 2.2 Opening Screen The Opening Screen of the FP35 hearing aid analyzer is the starting point and the returning point for all operations. To switch between coupler measurements, real-ear measurements, and the automated test sequences, you always go through the Opening Screen. It is also the only screen from which the Default Settings Menu is accessible. 2.2.
General Operation 25 2.2.3 Switching Between Settings The FP35 analyzer lets you save up to three different sets of default settings. You may want to set up your analyzer in different ways for testing analog hearing aids versus digital hearing aids. Or you may have multiple users, each with his own default settings preferences. See Section 2.3.1 for details on saving default settings setups. [F1] in the Opening Screen is normally used for switching between different setups.
26 FONIX FP35 Hearing Aid Analyzer 2.3.1 Customizing Your Instrument Default Settings All of the settings available in the Main, Advanced, and Resets Default Settings menus can be saved to the FP35 analyzer’s power-on default condition. In recognition that the FP35 might be used by several different users who might prefer different default settings, three different sets of defaults can be stored to SETTING 1, SETTING 2, and SETTING 3, respectively. To store the default settings: 1.
General Operation 27 2.3.3 Changing the use of [F1] in the Opening screen By default, [F1] is used in the Opening screen to switch between default settings, as described in Section 2.3.1. However, if you do not have a need for different sets of default settings, you can use it as a shortcut to any real-ear or coupler screen. Unlike [F2] and [F3], whose functions change depending upon the last real-ear or coupler multicurve screen you entered, the function of [F1] will remain constant.
28 FONIX FP35 Hearing Aid Analyzer The following 15 colors are available in each selection: BLACK, BLUE, GREEN, CYAN, RED, MAGENTA, YELLOW, GRAY, L BLUE, L GREEN, L CYAN, L RED, L MAGENTA, L YELLOW, WHITE. You cannot set both the VIDEO FOREGND and VIDEO BACKGND selections to be the same color except for BLACK and WHITE. If BLACK is selected as both the FOREGND and the BACKGND colors, both selections will change to DEFAULT display mode, which will follow the FP35 LCD display settings.
General Operation 29 AGE—The age of the patient. This is used for creating real-ear and coupler targets. Available with Real-Ear Option only. AID GROUP—Type of hearing aid being tested. Choose STANDARD, AGC, or ADAPTIVE (for adaptive AGC circuits). This selection sets the various delay times used in pure-tone tests so that they are appropriate to the aid’s circuitry. See Section 2.4 for more information on delay times. AID TYPE—Style of hearing aid being tested, used for creating coupler targets.
30 FONIX FP35 Hearing Aid Analyzer Real-Ear (only available with Real-Ear Option) REF MIC—Status of the reference microphone during real-ear measurements. NOISE RED (TONE)—The amount of noise reduction used in pure-tone real-ear measurements. See Section 2.5.1.3. NOISE RED (COMP)—The amount of noise reduction used in Composite or Digital Speech real-ear measurements. See Section 2.5.2.3 for more information.
General Operation 31 F3 KEY—Operation of the F3 key in the Opening screen. Choose from MULTICURVE (Coupler Multicurve), TARGET (Coupler Target), and EARSIM (Coupler EarSim). TARGET and EARSIM are only available with the Real-Ear Option. F4 & F5 KEY—Operation of the F4 and F5 keys in the Opening screen. These settings will appear only if you have more than two automated test sequences on your analyzer. These are the available choices: ANSI 96, IEC, JIS and ACIC (ANSI 96 with CIC correction factors).
32 FONIX FP35 Hearing Aid Analyzer OUTPUT LIMIT—The maximum dB SPL value that the analyzer will allow when taking coupler measurements. When this value is exceeded, the measurement will automatically stop and the source will turn off. SPEAKER—Selected source device.
33 General Operation 2.3.8 Explaining the Settings in the Resets Default Settings Menu The Resets Default Settings lets you set up your own default source levels. To reach it, press [MENU] from the Opening screen and then push [NEXT] twice. Coupler: CRV #1-4 SRC LEVEL: Set the default source level for curves 1-4 in the Coupler Multicurve, Coupler Target, and Coupler EarSim screens. STD/AGC/ADAPT PREDELAY/SETTLE: Set the default delays for each aid type and delay type displayed.
34 FONIX FP35 Hearing Aid Analyzer • The Long Settle time is the amount of time each frequency in an input/output sweep is presented before a measurement is made. It also sets the delay between the individual frequencies of three-frequency averages and distortion measurements.
35 General Operation • DIG SPCH—A randomly interrupted composite signal designed to mimic speech. This signal is for use with hearing aids with a “noise reduction” or “speech enhancing” feature that lowers the gain of the aid in the presence of a continuous signal (such as the regular composite signal). See Appendix F for more details. • LONG—A frequency response curve that measures 64 different frequencies, containing more information (and taking longer) than the standard NORM sweep. 2.5.
36 FONIX FP35 Hearing Aid Analyzer Historically, the harmonic distortion measurement has been taken only at signal levels below 90 dB SPL. This is because it was assumed that most hearing aids went into saturation at that loud of a level, resulting in very high harmonic distortion measurements. For this reason, we introduced a “90 dB harmonic distortion” rule on our analyzers that automatically turned off harmonic distortion measurements with signals that are 90 dB SPL or higher.
37 General Operation Here is an explanation of the available warble selections: • FAST is usually used in real-ear measurements. In all screens except the Audiogram Entry Screen, it warbles at a rate of 33 Hz. In the Audiogram Entry Screen, it warbles at a rate of 20 Hz, ±5% deviation from central frequency. • SLOW is used for testing digital hearing aids and for audiometric measurements. It warbles at a rate of 6.25 Hz, ±5% deviation. • OFF turns off all pure-tone warbling in all measurements.
38 FONIX FP35 Hearing Aid Analyzer 2.5.1.6 Three-Frequency Averages Three-frequency averages are usually performed within an automated test sequences. When the USER LEVEL is set to ADVANCED (see Section 2.3.2), you can also perform them from within the Coupler Multicurve, Target Coupler, or any of the real-ear measurement screens. The three frequencies that are used to perform the average measurements are chosen in a menu selection and represented by the last frequency of the three-frequency average.
39 General Operation 2.5.2.1 Filter Type Filters are the type of speech weighting applied to the test signals as they are presented to the hearing aid. By default, the FP35 analyzer automatically chooses the appropriate speech weighting to use with a particular type of signal. For instance, when you use a pure-tone signal, a flat weighting is used. That is, every frequency of the pure-tone sweep has the same amplitude. When you use the composite signal, the Frye ANSI speech weighting is used.
40 FONIX FP35 Hearing Aid Analyzer • FLAT with DSL fitting rule and pure-tone signal above 85 dB SPL • A-LTASS with DSL fitting rule for adults (all other signal types) • C-LTASS with DSL fitting rule for children (all other signal types) 2.5.2.2 Intermodulation Distortion 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.
General Operation 41 Harmonic Distortion measurement If desired, IM distortion tests can be performed with only one frequency instead of two. This turns the test into a simple harmonic distortion test. The only difference between this type of harmonic distortion test and the standard harmonic distortion test is that the results are displayed as a line on the graph instead of bars, and more frequencies can be measured than in the standard harmonic distortion measurement. See Section 2.5.1.
42 FONIX FP35 Hearing Aid Analyzer Here’s the technical details of the frequencies examined for those of you who are interested: 2ND: [F1 + F2] + [F1 – F2]_3RD: [(F1*2) + F2] + [(F1*2) – F2] + [(F2*2) – F1] + [(F2*2)+F1]_TOTAL: All frequencies excluding F1 and F2. (F1 and F2 are the primary frequencies of the IM distortion sweep.) Delays Just like a pure-tone sweep, you can change the delays in the IM distortion sweep.
General Operation 43 Default Settings When IM DIST is saved as the COUPLER or REAL-EAR RESET SRC in the Advanced Default Settings Menu, the IM FREQ DIFF, DISTORTION SWEEP, and DIST SWEEP END settings in the local menu will also be saved as default settings, even though these settings are not available in any of the Default Settings Menus. 2.5.2.3 Noise Reduction Composite noise reduction is a little different than pure-tone noise reduction (discussed in Section 2.5.1.
44 FONIX FP35 Hearing Aid Analyzer True RMS (TRMS) does not compensate for system response errors. It can be more accurate for measurements using external signal sources or measurements in an extremely noisy test environment. It is also a much faster measurement because it doesn’t use an FFT – using TRMS can speed up the measurement by nearly 50%. TRMS does contain a frequency response correction at 1 kHz, regardless of the selected frequency. TRMS cannot be used with the probe microphone.
45 General Operation TRMS: • RMS OUT will be measured as TRMS with Composite or Digital Speech. • ERMS will be measured with real-ear pure-tones at or above 85 dB SPL. • ERMS will be measured with coupler pure-tones at or above 90 dB SPL when the reference microphone is on. • TRMS will be measured with coupler pure-tones at or above 90 dB SPL when the reference microphone is off. NONE: • RMS OUT will not be measured for Composite or Digital Speech.
46 FONIX FP35 Hearing Aid Analyzer for a 3 dB error at 500 Hz, the reference quality will be “3.” Only the worst error is indicated. In order to minimize the effect of noise and other problems on the reference quality, only the frequencies between 260 Hz and 6000 Hz are checked for quality. Most of the chamber quality errors encountered will be the result of probe tube errors. Doing a custom calibration of the probe microphone with the probe tube that will be used with the measurement will improve this.
General Operation 47 5. Choose SPEAKER to enable only the speaker, MONO EAR to enable only the left channel of the earphone jack, STEREO EAR to enable both channels of the earphone jack, or ALL ON to enable both earphone jack channels and the speaker. 6. Press [EXIT] to return to the measurement screen. 2.5.6 Using Impulse Rejection Impulse rejection reduces the amount of noise measured in the testing environment by working together with the noise reduction setting.
48 FONIX FP35 Hearing Aid Analyzer Figure 2.5.7—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 and/or COUPLER with [∨, ∧] keys. Use [<, >] to make the selection. The SPEAKER selection under REAL-EAR selects whether the INTERNAL or EXTERNAL speaker will be used for realear measurements.
49 General Operation dard size of an insert earphone. The speaker jack was changed from a non-standard modular plug to a 3.5 mm connector. If you have the new style rear panel, you can use either the earphone jack or the speaker jack to connect the external telecoil board or the Telewand device. You will need a 3.5 mm to 1/4 inch adapter to use the earphone jack with the new rear panel. 1. Press [MENU] from the Opening Screen. 2. Use [∨, ∧] to select TELECOIL under COUPLER. 3.
50 FONIX FP35 Hearing Aid Analyzer 3. Connect the hearing aid to a coupler. Don’t insert the measurement microphone. 4. Walk around your possible testing location and listen for raspy humming sounds from the hearing aid. This will be the aid responding to magnetic fields in the room. 5. Pick a location that is as free of such sounds as possible. Rotate the aid in all directions when looking for a good site. 2.
General Operation 51 2.6.2 Adding a Label A label with your printout allows you to record useful information about the client and hearing aid to go along with the test results. See Figure 2.6.2. To view the label set on your analyzer, press [MENU] from the Opening screen to enter the Default Settings Menu, and then press [BACK]. This will display the label that will be printed on your analyzer whenever the labeled is turned on.
52 FONIX FP35 Hearing Aid Analyzer Note: With the RS232 Option, you can use a computer to store your own label and graphic logo in the FP35. A program called “Set Label,” available in the “download” section of our website www.frye.com, will help you change your analyzer’s label. The internal printer of the FP35 uses high quality thermal paper. This section will show you how to change the paper, fix any paper jams, and minimize the fading of the thermal printout. 2.6.
53 General Operation paper tape Side view of printer showing paper path Figure 2.6.3A—Paper path for FP35 Note: If the roll of paper is full, it can be difficult to grip. Loosen some of the paper, pinch it into a fold, and use the fold to pull the paper and spool out of the cavity, as in Figure 2.6.3B Figure 2.6.3B—Removing a full roll of paper 2.6.4 Fixing Paper Jams If you do not get a response from pressing the [PRINT/FEED] key, check for a paper jam.
54 FONIX FP35 Hearing Aid Analyzer print-outs away from the light in a cool, dry place. Do not store the strips in plastic or put cellophane tape on them, and avoid fingerprints. If you want to be absolutely certain that you will have data for many years, use a regular copier to duplicate the printed results. 2.6.6. Using an External Printer You can hook up an external printer to your FP35 analyzer to print your results on normal office paper.
General Operation 55 Figure 2.7.1—Display of numerical test data To use the data feature, select it as your DISPLAY in the menu: 1. Press [MENU]. 2. Select DATA/GRAPH using the [∨, ∧] keys. 3. Set DATA using the [<, >] keys. 4. Press [EXIT]. To see the numerical data of an existing curve, press [F2] to select desired curve. To gather new information, press [START/STOP], and a new curve will be run, updating the data table once the measurement is complete.
56 FONIX FP35 Hearing Aid Analyzer Figure 2.7.2—Curve ID box Number: This identifies the number of the relevant curve. The arrow to the right of these numbers indicates the current selected curve. Source: This identifies the amplitude of each curve. Type: The curve type is a little more complicated; each curve is identified by three letters.
Chapter 3 57 Coupler Measurements Coupler measurements are electro-acoustical tests performed using a coupler acting as an artificial ear inside the sound chamber. This chapter describes how to perform coupler measurements manually in the Coupler Multicurve screen. For instructions on how to perform ANSI, IEC, or other automated test sequences, see Chapter 4, Automated Test Sequences.
58 FONIX FP35 Hearing Aid Analyzer 1. Type of display. This will be either dB SPL (coupler output) or dB Gain (coupler gain). Select between the two in [MENU]. 2. Displays leveling status of the sound chamber. See Section 3.2 for more information. 3. Displays the signal and weighting types used with the selected curve. 4. N.R. = Noise reduction. Select this in [MENU]. 5. Status of reference microphone. Select this in [MENU]. 6.
Coupler Measurements 59 Figure 3.2.1—Normal leveling setup 3.2.1 Leveling without the Reference Microphone (Standard) Leveling the sound chamber using only the measurement microphone is accurate enough for most clinical tests. 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.
60 FONIX FP35 Hearing Aid Analyzer 3.2.2 Leveling Using the Reference Microphone If your analyzer has the M300 two microphone setup, you can level using the probe microphone as a reference microphone. If you choose to do this type of leveling, you will need to level every time the hearing aid set up changes significantly (e.g. you begin to test a different style or model of aid). This method is more exact than the general purpose leveling described in the previous section and performed at the factory.
Coupler Measurements 61 3.2.3 Saving the Leveling Information The FP35 can store leveling so that you do not need to re-level the sound chamber every time you turn on the FP35 analyzer. To store 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 [∨, ∧] keys to move the cursor to the selection “Store Chamber Leveling in EEROM” 4. Press [START/STOP]. The FP35 will confirm that you want to store the leveling. 5.
62 FONIX FP35 Hearing Aid Analyzer 3.3 Hearing Aid Setup To set up the analyzer and the hearing aid for testing, you connect the hearing aid to a coupler. The standard couplers of the FP35 analyzer are the HA-1 and HA-2 couplers. These couplers contain 2 cc of space, simulating the amount of place in a person’s ear canal. The procedure for connecting a hearing aid those couplers are described in this section.
Coupler Measurements 63 3.3.2 Setting up an ITE Roll the Fun-Tak, provided with each instrument, into a rod long enough to go around the transmitting end of the aid (approx. 2 in or 5 cm). Modeling clay can also be used, but it doesn’t work as well. Bend the Fun-Tak rod around the canal end of the aid, making the resulting “donut” flush with the end of the aid. (Some users choose to seal the vent opening at this end with a small amount of Fun-Tak.
64 FONIX FP35 Hearing Aid Analyzer Press down on the Fun-Tak with a pencil or your finger to create an acoustic seal between the aid and coupler. You may want to double-check the aid placement through the open end of the coupler at this point. Slowly insert the microphone into the coupler. You may feel an initial resistance when the mic reaches the O-ring. Continue to push the microphone until it stops. Place the completed assembly over the center of the speaker in the test chamber.
Coupler Measurements 65 3.4.1 Running a Test Curve 1. Enter the Coupler Multicurve screen by pressing [F3] from the Opening screen. If the Coupler Target or Coupler EarSim screen is displayed when you do this, instead of the Coupler Multicurve screen, use the [NEXT] key. 2. Press [MENU] from the Coupler Multicurve screen to make any necessary selections. See Section 3.9 for details. 3. Level the sound chamber as described in Section 3.2, if necessary. 4.
66 FONIX FP35 Hearing Aid Analyzer Figure 3.4.1A shows a completed normal pure-tone sweep. Example Following the instructions above, run 4 Gain curves using amplitudes 50, 60, 70, and 80 dB SPL. Use a signal source of NORM, COMP, or DIG SPCH. This scenario will provide you with a family of curves. Whenever the curves sit on top of each other, the gain of the aid is the same for the amplitudes of those curves. This indicates the aid is running linearly.
Coupler Measurements 67 Figure 3.4.1C—This aid shows a great deal of compression between 50 dB and 90 dB. 3.4.2 Running a Single Frequency Measurement At times, you may want to find out what the frequency response of the hearing aid is to a single pure-tone signal. 1. Push [F4] and hold the key down for half a second until the Source Selection box appears. 2. Use [∧,∨] to choose SINGLE. 3. Press [START] to make the selection and close the selection box. 4.
68 FONIX FP35 Hearing Aid Analyzer Figure 3.4.2—Measuring a single frequency 3.5 Distortion Measurements There are several different methods to measure distortion in a hearing aid. This section describes how to measure harmonic distortion and intermodulation distortion. 3.5.1 Measuring Harmonic Distortion Harmonic distortion is when the hearing aid returns energy at frequencies not present in the source signal. The FP35 allows you test for this phenomenon very easily. See Section 2.5.1.
Coupler Measurements 69 In the past, FONIX analyzers have not measured harmonic distortion when the signal level was set to 90 dB SPL or higher. This is called the “90 dB harmonic distortion rule.” Since hearing aids in recent years have become more sophisticated and able to handle loud signals, we have turned this off this rule by default. However, if you would like to use it, first set the USER LEVEL to ADVANCED in the Default. See Section 2.3.2 for details.
70 FONIX FP35 Hearing Aid Analyzer 3. Press [NEXT] to enter the Advanced menu. 4. Select IM FREQ DIFF using [∨, ∧]. 5. Use [<, >] to select the fixed distance between the primary and secondary frequencies used in the measurement. You can choose from no distance (HARM) to 4000 Hz. 6. Press [EXIT] to return to the Coupler Multicurve screen. 7. Press and hold down [F4]. This will pop up a list of the available selections, including DIST. 8. Use [∧,∨] to select DIST. Figure 3.5.
Coupler Measurements 71 3.5.3 Performing an IM Distortion Sweep In the IM distortion sweep test, the FP35 analyzer produces a sweep of the two frequency combination mentioned in the section above. This is similar to a normal pure-tone frequency sweep, but two frequencies are used at a time instead of one at a time. The FP35 analyzer measures the IM distortion by looking at frequencies that have a mathematical relationship to the primary frequencies.
72 FONIX FP35 Hearing Aid Analyzer 8. Press [EXIT] to return to the Coupler Multicurve screen. 9. Use [∨, ∧] to select the RMS source of the test. Each frequency will have an amplitude 3 dB less than the RMS source. 10. Set up the aid for test in the sound chamber as usual. Make sure to close the lid of the sound chamber. 11. Press [START/STOP] to perform the IM distortion sweep. See Figure 3.5.3 for an example. The percentage scaling for the measurement is located on the right side of the graph.
Coupler Measurements 73 2. Use [∨, ∧] to select NOISE REDUCTION. 3. Use [<, >] to set the level of noise reduction. This must be at least 2X. 4. Press [NEXT] twice to enter the Custom menu. 5. Use [∨, ∧] to select IMPULSE REJ. 6. Use [<, >] to select the amount of impulse rejection you would like in the IM distortion test. Lower values will make the FP35 analyzer reject more measurements. Higher values will make the FP35 analyzer less sensitive. 7.
74 FONIX FP35 Hearing Aid Analyzer 4. Select CIC with the [<, >] keys. 5. Press [EXIT]. 6. Select the desired source type with [F4]. 7. Select the desired source amplitude with the [∨, ∧] keys. 8. Press [START/STOP] to perform the measurement. You should see CPLR CIC appear on the right column of the screen. If necessary, press [START/STOP] to end measurement. Figure 3.
75 Coupler Measurements 1. Attach the MZ coupler to the aid. See Table 3.7 for details on choosing the correct MZ coupler. 2. Set up the hearing aid for testing as described in Chapter 3. 3. Press [MENU] from the Coupler Multicurve screen. 4. Highlight COUPLER TYPE with the [∨, ∧] keys. Table 3.7—Which is the Correct MZ Coupler to use? TYPE OF AID COUPLER COMMENT ITE, ITC MZ-1 BTE, or EYEGLASS MZ-1 With custom earmold attached. (NOTE: Vents must be plugged.
76 FONIX FP35 Hearing Aid Analyzer Figure 3.7—Comparison of the responses with the MZ and HA-2 couplers 3.8 Advanced Testing This section contains information of interest to the advanced user including instructions for testing digital and directional aids, and procedures for reversing and splitting the measurement microphones. 3.8.1 Testing Digital Hearing Aids The FP35 seamlessly incorporates the testing of digital hearing aids into its normal testing procedures.
Coupler Measurements 77 Confusion with Terminology With the new testing technology of hearing aid analyzers combined with the new technology of hearing aids, it’s easy to get terminology confused. Frye Electronics has always used “noise reduction” to denote the averaging that the analyzer makes when analyzing data, as described in Section 2.5.1.3 and Section 2.5.2.3. Some high-end hearing aids have a function often referred to as “speech enhancement” or “noise reduction.
78 FONIX FP35 Hearing Aid Analyzer 4. Enter the Coupler Multicurve screen. 5. Press [MENU] to open the local menu. 6. Use the arrow keys to make sure that DISPLAY is set to GAIN and REF MIC is set to OFF. 7. Press [NEXT] to enter the Advanced menu. 8. Use the arrow keys to change LEVELING SOURCE to 70 dBSPL. 9. Press [EXIT] to close the local menu and return to the Coupler Multicurve screen. 10. Hold the measurement microphone about six inches from the speaker, and press [F5] to level it. See Figure 3.8.
Coupler Measurements 79 Figure 3.8.2C—Make the measurement 16. Press [START/STOP] to start the measurement. When it stabilizes, press [START/STOP] to stop the measurement. 17. Press [F1] to select CRV 2. 18. Repeat Steps 9-10 to select the same source type and level as used for CRV1. 19. Press [START/STOP] to start the measurement. As it is running, slowing rotate the hearing aid, maintaining the same distance from the sound field speaker.
80 FONIX FP35 Hearing Aid Analyzer Figure 3.8.2D—Comparison of the directional response of the hearing aid at 0 °(CRV1) and 180 °(CRV2) 3.8.3 Testing with the Reference Microphone If your FP35 has the M300 microphone, you have two microphones available for taking measurements. The normal, recommended method for taking coupler measurements involves the use of just the coupler microphone.
Coupler Measurements 81 Figure 3.8.3—Testing using the reference microphone If you choose to use the reference microphone, you should use the leveling procedure described in Section 3.2.2. 1. Press [MENU] 2. Select REF MIC using the [∨, ∧] keys. 3. Set REF MIC to ON using [<, >] keys. 4. Press [EXIT] to exit from menu. 5. Set up the aid as described in Section 3.3. 6. Place the tip of the probe microphone as close as possible to the hearing aid microphone without touching it. 7. Test as usual.
82 FONIX FP35 Hearing Aid Analyzer To reverse the microphones: 1. Press [MENU] from Coupler Multicurve screen. 2. Press [NEXT] twice to enter the Custom Menu. 3. Highlight MICROPHONES. 4. Use the [<, >] keys to select REVERSE. 5. Press [EXIT] to return to Coupler Multicurve Mode. Once you have reversed the microphones by following the above procedure, the coupler multicurve screen will be slightly altered.
Coupler Measurements 83 Figure 3.8.5—Curve 1 is the measurement microphone. Curve 2 is the reference microphone 3.8.6 Changing the Signal Filters Filters are the type of speech weighting applied to the test signals as they are presented to the hearing aid. By default, the FP35 analyzer automatically chooses the appropriate speech weighting to use with a particular type of signal. For instance, when you use a pure-tone signal, a flat weighting is used.
84 FONIX FP35 Hearing Aid Analyzer 3.8.7 Running a Three-Frequency Average The ANSI and IEC automated test sequences call for running three frequency average measurements. This can be done in the Coupler Multicurve screen when the USER LEVEL is set to ADVANCED in the Default Settings menu. See Section 2.3.2 for details. To measure the three frequency average: 1. Select a signal type of NORM with [F4] in the Coupler Multicurve screen. 2. Check the bottom left corner of your screen.
Coupler Measurements 85 4. Use [∨, ∧] to select TELECOIL and use [<, >] to choose ON. 5. Press [EXIT] to close the local menu. The source box at the bottom of the measurement graph will now indicate TMFS. 6. Follow the instructions in the Telecoil Board Setup or Telewand Setup sections below, depending upon the device you are using for your telecoil measurements.
86 FONIX FP35 Hearing Aid Analyzer Figure 3.8.8A—Orienting hearing aid for maximum output Telewand Setup Follow these instructions for setting up the hearing aid and the FP35 analyzer for telecoil measurements using the Telewand. 1. Plug the Telewand into the earphone jack or the speaker jack (new style rear panel only) on the back of the FP35 analyzer. 2. Attach the hearing aid to a coupler in the usual way and set the hearing aid to telecoil mode. 3.
Coupler Measurements 87 Figure 3.8.8B—Using the Telewand 3.9 Reference This section contains specific information on the function of each of the function keys, and the function of each available menu item. The menu system in the Coupler Multicurve Mode has been divided into three different screens: the Primary Menu, the Advanced Menu, and the Custom Menu. The Primary Menu contains the most basic selections; things you may want to change frequently.
88 FONIX FP35 Hearing Aid Analyzer 3.9.2 Explaining the Menu Items This section describes the menu selections available in the Coupler Multicurve screen. When the USER LEVEL is set to EASY in the Default Settings menu (see Section 2.3.2 for details), fewer menu items are available. The items starred (*) below are only available when the USER LEVEL is set to ADVANCED.
Coupler Measurements 89 Advanced Menu For more advanced control of your unit, press [NEXT] to go to the Advanced Menu. *AUTO-SCALE—The type of scaling used. ON scales the graph to the selected curve. OFF scales the graph to the highest curve displayed. *REFERENCE STATUS—The type of RMS measurement made with the reference microphone.
90 FONIX FP35 Hearing Aid Analyzer Custom Menu Press [NEXT] from the Advanced Menu to enter the Custom Menu. *OUTPUT LIMIT—Level of output limiting, which shuts off the source when the measured signal exceeds the limit set here. Choices are: OFF; 80-140 dB SPL. This is usually used only for real-ear type measurements. *WARBLE SOURCE—The warble rate in pure-tone signals. Warble is usually used in sound field speaker measurements to reduce problems caused by standing waves.
Coupler Measurements 91 *MICROPHONES—Special operational selections for your microphones. Choices are NORMAL, REVERSE, and SPLIT. See Sections 3.8.4 and 3.8.5 for more details. *SPECTRUM WINDOW—When performing spectrum analysis of random signals such as speech or room noise, leave this ON. If you would like to perform a spectrum analysis of a “phase synchronous” signal such as might be found in one of our other instruments, turn this OFF. See Chapter 9 for more details.
Chapter 4 93 Automated Test Sequences There are several different automated test sequences available with the FP35 analyzer. One test sequence of your choice is included as a standard feature when the FP35 is ordered. The other test sequences can be added as optional features. The available automated test sequence include: ANSI 96, ANSI 03, IEC, JIS, and ISI. 4.1 The ANSI Sequence The ANSI test sequence allows you to test hearing aids according to the ANSI S3.22 standard.
94 FONIX FP35 Hearing Aid Analyzer 4.1.1 Viewing the ANSI ’96 Display Figure 4.1.1A—ANSI 96 test results, Frequency Response Screen Figure 4.1.
Automated Test Sequences 95 Refer to Figure 4.1.1A and 4.1.1B for the following explanation of the graphical display: 1. OSPL 90 curve: full-on gain frequency sweep taken at 90 dB SPL. 2. RESP 50 curve: reference test gain frequency sweep taken at 50 dB SPL. 3. FOG: amplitude of the full-on gain measurement. 4. HFA/SPA: three frequency average chosen in the MENU. 5. OSPL 90 HFA: three frequency average of the OSPL 90 curve. 6. MAX: amplitude and frequency of the maximum output of the aid. 7.
96 FONIX FP35 Hearing Aid Analyzer 4.1.3 Leveling Before you run an ANSI test, you should make sure the sound chamber is leveled. Even if the screen says that the chamber is leveled, it is a good idea to periodically re-level it to account for any differences that might have entered into the testing environment. The ANSI standard requires that you do a special leveling that accounts for everything that will be in the chamber during the test.
Automated Test Sequences 97 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. If you are unsure which to choose, press [EXIT] to return to the Main Screen and [F3] to enter the Coupler Multicurve screen. Run a full-on SPL curve at 60 dB and at 90 dB. (See Section 3.4.
98 FONIX FP35 Hearing Aid Analyzer 4.1.6 Running an ANSI Test After making any necessary menu selections as described in Section 4.1.8, leveling the sound chamber as described in Section 3.2, and setting up the aid as described in Section 3.3, follow these instructions: 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.
Automated Test Sequences 99 In order to test digital hearing aids with “noise reduction” or “speech enhancement” features to the ANSI 96 or ANSI 03 standards, put the aid in “test” mode via its programming software and do the steps outlined in Section 4.1.6.
100 FONIX FP35 Hearing Aid Analyzer Advanced ANSI Menu Reach the following menu choices by pressing [NEXT] while the main menu is open. HDIST 12DB—Status of the harmonic distortion rule. The ANSI standard states that when measuring harmonic distortion, if the amplitude of the response curve at second harmonic of the distortion frequency is 12 dB greater than the response curve at the distortion frequency, the harmonic distortion measurement should be ignored. Choose ON to apply this rule.
Automated Test Sequences 101 3. RESP: reference test gain frequency sweep taken at 60 dB SPL. 4. Aid type. Select with [F1]. 5. Leveling status. 6. OSPL90 REF: frequency response of OSPL90 curve at reference frequency (1600 or 2500 Hz). Select with [F3]. 7. MAX: amplitude and frequency of the maximum output of the aid. 8. CALC: target reference test gain 9. MEAS: measured reference test gain 10. TOT H DIST: total harmonic distortion measured at frequency selected in [MENU]. 11.
102 FONIX FP35 Hearing Aid Analyzer Figure 4.2.1B—IEC test results, I/O Screen 4.2.2 Defining the Function Keys [F1] Selects aid type: LINEAR, AGC, or ADAPTIVE AGC. [F2] Selects whether full-on gain curve will be run at 50 dB or at 60 dB. [F3] Selects the reference test position to be 1600 Hz or 2500 Hz. [F5] Levels the sound chamber. 4.2.3 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.
Automated Test Sequences 103 4.2.4 Running an IEC Test 1. Level the sound chamber as described in Section 3.2, if needed. 2. Push the [START/STOP] key. 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.
104 FONIX FP35 Hearing Aid Analyzer LONG SETTLE—The time delay between the frequencies of three frequency averages and distortion measurements. PRINT LABEL— Status of the printing label. Choose ON or OFF. PRINTER— Printer used for printouts. Choose INTERNAL to use the built-in thermal printer. Choose EXTERNAL to use an attached laser or ink-jet printer. 4.3 JIS Testing The JIS 2000 automated test sequence allows you to test hearing aids according to the Japanese Instrument Standard.
Automated Test Sequences 105 F2: frequency at which the RESP 50 (or 60) curve crosses the response limit level on the way down. 16. TOT H DIST: total harmonic distortion measurements and the frequencies and amplitudes at which they are taken. 17. I/O CURVE: input/output curve at reference frequency (1600 or 2500 Hz). Select with [F3]. Figure 4.3.
106 FONIX FP35 Hearing Aid Analyzer Figure 4.3.1B—JIS test results, I/O Screen 4.3.2 Defining the Function Keys [F1] Selects aid type: LINEAR, AGC, or ADAPTIVE AGC. [F2] Selects whether the full-on gain curve will be run at 50 dB or at 60 dB. [F3] Selects the reference test position to be 1600 Hz or 2500 Hz. [F5] Levels the sound chamber. 4.3.3 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.
Automated Test Sequences 107 4.3.4 Running the JIS Test 1. Make sure the sound chamber is leveled. Follow the instructions found in Section 3.3, if needed. 2. Push the [START/STOP] key. 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.
108 FONIX FP35 Hearing Aid Analyzer ment should be ignored. Choose ON to apply this rule. Choose OFF to ignore this rule. PREDELAY TIME—The delay after the first tone is presented and before the first measurement is taken. See Section 2.4 for more information.. SHORT SETTLE—The time delay between the frequencies of pure-tone sweeps and input/output curves. LONG SETTLE—The time delay between the frequencies of three frequency averages and distortion measurements. PRINT LABEL— Status of the printing label.
Automated Test Sequences 109 5. Amplitude used to measure the full-on gain curve 6. Reference frequency 7. Leveling status 8. OSPL90 HFA: High frequency average of the OSPL90 curve 9. OSPL90 MAX: Maximum output of the OSPL90 curve and the frequency at which it was measured 10. FOG: Reference frequency response made at full-on gain 11. HFA: High frequency average made at full-on gain 12. CALC: Calculated reference test gain 13. Equivalent input noise 14.
110 FONIX FP35 Hearing Aid Analyzer Figure 4.
Chapter 5 111 Real-Ear Measurements 5.1 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 test available of the hearing aid’s performance because it is measured 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. 5.1.
112 FONIX FP35 Hearing Aid Analyzer Audiogram Entry Real-Ear SPL Insertion Gain Real Ear Unaided & Aided Figure 5.1.2—Real-ear navigation using next and back keys 5.2 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. 5.2.
Real-Ear Measurements 113 Note: If you are using a 90 dB signal, 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. 5.2.2 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.
114 FONIX FP35 Hearing Aid Analyzer • 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. 5.2.3 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.
115 Real-Ear Measurements 5.2.4 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 5.2.4A 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.
116 FONIX FP35 Hearing Aid Analyzer 5.2.5 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 5.2.1 for a diagram of a client being tested at 45 degrees azimuth.
Real-Ear Measurements 117 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. Only the larger reference microphone is used during the leveling process.
118 FONIX FP35 Hearing Aid Analyzer 5.2.7 Testing Digital Aids The FP35 seamlessly incorporates the testing of digital hearing aids into its normal testing procedures. If you have the Composite/Digital Speech Option, just follow the steps outlined in Section 5.4.4 (Insertion Gain) or Section 5.5.2 (SPL), choosing a signal source of DIG SPCH with [F4] in the Real-Ear Testing Screens. The Digital Speech signal is an interrupted composite signal designed to imitate the rhythms of speech.
Real-Ear Measurements 119 5.3 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. 5.3.1 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.
120 FONIX FP35 Hearing Aid Analyzer The display will change, depending upon the selection made with [F2]: • A selection of HTL or UCL displays the audiometric information in dB HL • A selection of TARGET displays the target curve in dB insertion gain or dB SPL. • A selection of RECD or REDD displays that data in dB gain. 5.3.3 Entering Audiometric Information & Creating A Target Use the following instructions to create a non-NAL-NL1 target. See Section 5.3.4 for NAL-NL1 instructions.
Real-Ear Measurements 121 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.
122 FONIX FP35 Hearing Aid Analyzer 12. Repeat Steps 3-4 to enter the audiogram for the new ear. 13. Press [F3] to generate the NAL-NL1 target. If you did not enter any measured UCL values, predicted UCLs will also be generated. 5.3.5 Modifying a Target If the target generated by the FP35 does not meet your client’s needs, you can modify it so that it does. To modify the target: 1. Press [F2] until TARGET is selected. In the data entry box, the cursor will now be in the TARG column. 2.
Real-Ear Measurements 123 5. Press [<, >] to select INS. EAR. 6. Press [EXIT] to return to Audiogram Entry Screen. 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.
124 FONIX FP35 Hearing Aid Analyzer Foam eartip 3A IN EARSERT PHO NE Probe mic Probe mic Figure 5.3.6.2A—Insert probe microphone Figure 5.3.6.2B—Insert foam eartip connected to insert microphone 5.3.6.3 Taking the RECD Measurement If you’ve performed the steps described in Sections 5.3.6.1 and 5.3.6.2, 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.
125 Real-Ear Measurements WARNING Choose OUTPUT LIMITING carefully (see procedure below). You don’t want to damage your client’s hearing or cause discomfort during testing. To ensure safety and comfort, the FP35 system reacts automatically when the OUTPUT LIMITING level is exceeded at the Probe Microphone. When the level measured at the Probe Microphone exceeds the pre-set limit, the words “PROBE OUTPUT LIMIT EXCEEDED” appear on the screen, and program automatically stops.
126 FONIX FP35 Hearing Aid Analyzer SANITATION NOTICE DO NOT REUSE PROBE TUBES. Use a new probe tube for each ear to prevent the possible spread of infection. Sterilization of probe tubes is not possible, and germicidal solutions can leave a residue inside the tubing which can result in errors. Do not cut off any portion of the tube. DO NOT REUSE INSERT EARPHONE EARTIPS. Insert earphone eartips are used primarily for performing RECD and audiometric measurements.
Real-Ear Measurements 127 Follow the directions in Section 5.3.6 to obtain an REDD using an insert earphone. Follow the directions in Section 5.3.8 to obtain an REDD using the sound field speaker. After performing the measurements, press [F5] to toggle the view to show REDD. When TDH is the selection for the ASSESSMENT field, the REDD cannot be measured automatically with the FP35 analyzer. Instead, the average values will be used, or measured values can be entered manually.
128 FONIX FP35 Hearing Aid Analyzer If you measure the unaided response in the Audiogram Entry screen, the measurement results will be copied into the Unaided and Aided screen for use with insertion gain measurements. Likewise, any unaided measurement made in one of the real-ear measurement screen will be copied into the Audiogram Entry screen. 1. Press [MENU] in the Audiogram Entry Screen. 2. Select the desired EAR using the arrow keys. 3. Select SPEAKER in the ASSESSMENT field using the arrow keys. 4.
Real-Ear Measurements 129 5.3.9 Starting a New Client When you have finished performing the real-ear (or target coupler) measurements on the hearing aid and patient, pressing [F1] in the Audiogram Entry screen will erase all measurements and restore settings in order to make setting up for a new patient quick and easy. In addition to all audiometric and real-ear measurements being erased, the following menu items are reset when [F1] is pressed in the Audiogram Entry screen.
130 FONIX FP35 Hearing Aid Analyzer EAR—The ear tested. Select LEFT or RIGHT. AID GROUP—Type of aid being tested. Choose STANDARD, AGC, or ADAPTIVE (for adaptive AGC circuits). See Section 2.4 for more information. ASSESSMENT—The transducer used in performing the audiometric measurements. If you have the Audiometer Option, this will activate the selected transducer. (The FP35 cannot use the TDH transducer to make audiometric measurements.
Real-Ear Measurements 131 FIT TYPE—Type of fitting Choose from UNILATERAL and BILATERAL. Bilateral fittings require the audiograms of both ears to be entered.This is only available with a fitting rule selection of NAL-NL1. AID TYPE—Style of hearing aid. Choose from BTE, ITE, ITC, and CIC. VENT—Type of venting on the hearing aid. Choose from OPEN, TIGHT, NO VENT, 1 mm, 2 mm, and 3 mm. This selection is only available with a fitting rule selection of NAL-NL1. TUBING—Type of tubing on the BTE hearing aid.
132 FONIX FP35 Hearing Aid Analyzer 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 5.4A. The Insertion Gain screen displays the insertion gain target and lets you measure and view insertion gain measurements of the hearing aid. See Figure 5.4B.
Real-Ear Measurements 133 Figure 5.4B—Insertion Gain Screen 5.4.1 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 5.2.4. Level the sound field speaker. See Section 5.2.6. 2.
134 FONIX FP35 Hearing Aid Analyzer Figure 5.4.1—Unaided response 8. If you used the composite signal for testing, use the [<,>]keys to show the last four measurements taken while the signal source was running. 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]. 5.4.2 Measuring the Aided Response The second step in an insertion gain measurement is the aided response.
Real-Ear Measurements 135 2. Have the client set the aid’s gain control to the normal use level. 3. Press [F4] to select the source type. 4. Use the [∨, ∧] keys 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.
136 FONIX FP35 Hearing Aid Analyzer Figure 5.4.2B—Insertion gain 5.4.3 Automatic Testing 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.
Real-Ear Measurements 137 To test directionality: 1. Place the probe tube in your client’s ear as described in Section 5.2.4, and level the sound field speaker as described in Section 5.2.6. Although we 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.
138 FONIX FP35 Hearing Aid Analyzer Figure 5.4.4A—“Reverse” directional aid setup Figure 5.4.
Real-Ear Measurements 139 Figure 5.4.4C—Amount of amplification advantage provided by the directional microphones 5.4.5 Testing Open Fit Hearing Aids Open fit hearing aids have been known to interfere with the reference microphone measurement outside the ear. To determine if a particular hearing aid is interfering with the reference microphone, perform the following measurement in any real-ear measurement screen.
140 FONIX FP35 Hearing Aid Analyzer 5. Measure the aided response as described in Section 5.4.2. • The source amplitude should be set to 65 dB SPL. Use the up-down arrow keys to adjust the source if necessary. • [F4] should be set to DIG SPCH. 6. Press [START/STOP] to start the measurement. Press [START/STOP] again when the measurement has stabilized. 7. Look at the difference between AIDED 1 and AIDED 2.
Real-Ear Measurements 141 5.5.1 The SPL Display The information on the SPL screen is similar to the information in the other real-ear 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.
142 FONIX FP35 Hearing Aid Analyzer 4. Press [F5] to level. 5. Have the client turn the aid on and set the gain control to the normal use level. 6. Use [F2] to select AIDED 1. 7. Use [F4] to select the source type for AIDED 1, and use the [∨, ∧] keys to set the source amplitude 8. If necessary, adjust noise reduction and output limiting with [MENU]. 9. Have the client resume the position they were in during leveling, and remind them to stay still while the signal is on. 10. Press [START/STOP] to test.
Real-Ear Measurements 143 5.5.3 Important Notes on SPL Testing This section contains somewhat technical details relating to the real-ear SPL screen. 5.5.3.1 Speech-Weighting Effects on Pure tones When the normal pure-tone or fast sweep of less than 85 dB is chosen as an SPL source signal, it is always speech weighted. The corresponding target is also speech weighted. The measurements and the target will therefore look different from the target curves displayed in the Insertion Gain Mode. 5.5.3.
144 FONIX FP35 Hearing Aid Analyzer 5.5.4 Important Notes on DSL Testing The DSL fitting method is slightly more complicated than the other fitting rules available on the FP35 analyzer. For this reason, it is important to keep a few things in mind when using DSL: • DSL was initially developed for children. For this reason, it is important to input the client’s age when generating a target for a child. If no age for the client is set, the analyzer will assume that it is generating a target for an adult.
Real-Ear Measurements 145 5.6 Live Speech Testing The Spectrum Analysis mode, available with the Composite/Digital Speech Option, lets you use the external signal of your choice with your real-ear measurements. You can use sounds from a CD player, the patient’s own voice, or the voice of a spouse or family member. This section describes several different methods of using external signal in your real-ear measurements.
146 FONIX FP35 Hearing Aid Analyzer more gradually with more averaging. If the noise reduction is turned to a low number or OFF, the measurement curve will update more quickly with less averaging. 10. Press [EXIT] to close the local menu. To start measuring: 1. Press [START/STOP] to start the measurement. 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.
Real-Ear Measurements 147 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. Notes The target displayed in the Real Ear SPL screen when in spectrum analysis mode assumes a 60 dB SPL input level. 5.6.2 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.
148 FONIX FP35 Hearing Aid Analyzer 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 [∨] 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.
Real-Ear Measurements 149 The USER LEVEL must be set to ADVANCED in the Default Settings menu. See Section 2.3.2 for details. 1. Press [MENU] from any real-ear measurement screen. 2. Press [NEXT] to enter the Custom menu. 3. Select DISTORTION using the [∨, ∧] keys. 4. Select the distortion type desired by using the [<, >]keys. See below for definitions of distortion types. 5. Press [EXIT]. 6. Press [F4] to select NORM. 7. Press [START/STOP] to run normal frequency sweep. Figure 5.7.
150 FONIX FP35 Hearing Aid Analyzer 5.7.3 Measuring Intermodulation Distortion This section describes how to make various intermodulation distortion measurements. See Section 2.5.2.2 for technical details on those measurements. The USER LEVEL must be set to ADVANCED in the Default Settings menu. See Section 2.3.2 for details. 5.7.3.1 To perform a static IM distortion test 1. Press [MENU] in the real-ear measurement screen to enter the real-ear menu. 2. Make sure the REF MIC is OFF.
Real-Ear Measurements 151 Figure 5.7.3.1—Real-Ear static IM distortion test 5.7.3.2 To perform an IM distortion sweep 1. Press [MENU] in the real-ear measurement screen to enter the real-ear menu. 2. Make sure the REF MIC is OFF. Use the arrow keys to make this selection, if necessary. 3. Press [NEXT] twice to enter the Custom menu. 4. Select DISTORTION with [∨, ∧]. 5. Use [<, >] to select the harmonics where the IM distortion will be measured.
152 FONIX FP35 Hearing Aid Analyzer Figure 5.7.3.2—Real-Ear IM distortion sweep 13. Set up the client, the aid, and the analyzer for real-ear testing. Make sure to level the sound field speaker. 14. Press [START/STOP] to start the IM distortion sweep. See Figure 5.7.3.2. The measurement will stop when finished. The percentage scaling for the measurement is located on the right side of the graph. Notice the thick line below the lower right corner of the graph.
Real-Ear Measurements 153 5. Press [EXIT] to return to the real-ear measurement screen and follow the directions in Section 5.7.3.2 to perform the IM distortion sweep. 5.7.4 Using the Reference Microphone The larger microphone that sits on top of the client’s ear is always used for leveling the sound field speaker. It can also be used in real-ear gain and insertion gain measurements.
154 FONIX FP35 Hearing Aid Analyzer Figure 5.7.5—Numerical display of target data 5.7.6 Measuring the Telecoil Response Telecoil measurements can be performed in the real-ear measurement screens using any source type available on the analyzer. You must use the optional Telewand to perform this measurement. To test the telecoil function in a real-ear measurement: 1. Follow the instructions found in Section 2.5.8 to set up the FP35 Default Settings Menu for telecoil measurements. 2.
Real-Ear Measurements 155 10. Instruct the patient to hold the Telewand next to his ear as if he were holding a telephone receiver next to his ear. See Figure 5.7.6A. 11. Press [START/STOP] to run the measurement and test as desired. See Figure 5.7.6B. Figure 5.7.6A—Measuring telecoil response with the Telewand. Figure 5.7.
156 FONIX FP35 Hearing Aid Analyzer 5.8 Reference This section contains a description of the real-ear measurement displays and definitions for each menu item available in the real-ear measurement screens. 5.8.1 Viewing the Real-Ear Screens The display for each of the three Real-Ear Measurement Screens has similar information. Please refer to Figures 5.8.1A, 5.8.1B, and 5.8.1C for the following listing. 1. Ear tested. Select with [MENU]. 2. Leveling status. See Section 5.2.6. 3.
Real-Ear Measurements Figure 5.8.1B—Insertion Gain Screen. Figure 5.8.
158 FONIX FP35 Hearing Aid Analyzer The Real-ear SPL and Real-ear Insertion Gain screens also contain information about the settings used to create the target: Not all settings are available with all targets. 10. Age of patient 11. Fitting rule selected and the type of fitting. “U” indicates a unilateral fitting. “B” indicates a bilateral fitting. 12. Compression threshold of the aid, number of channels of the aid, and the type of output limiting. “W” indicates wideband limiting.
Real-Ear Measurements 159 OUTPUT LIMIT—Level of output limiting. Please review red warning page. NOISE RED (TONE & COMP)—Select the amount of noise reduction suitable to your environment. See Section 2.5.1.3 and 2.5.2.3 for more details. REF MIC—The status of the reference microphone. Target Menu Press [BACK] from the Main Real-Ear menu to enter the Target menu. FIT RULE—The fitting rule used to create the real-ear and coupler targets.
160 FONIX FP35 Hearing Aid Analyzer *TABULATION—Target data display on the right side of the real-ear measurement screen. Choose TARGET or NONE. See Section 5.7.5 for details. *REFERENCE STATUS—The type of RMS measurement made with the reference microphone. The following selections are available: RMS displays the overall RMS of the reference microphone, FULL displays the overall RMS and the signal quality of the reference microphone, and NONE turns off the RMS display of the reference microphone.
Real-Ear Measurements 161 *WARBLE SOURCE—The warble rate in pure-tone signals. Warble is usually used in sound field speaker measurements to reduce problems caused by standing waves. See Section 2.5.1.4 for more details. *SIGNAL SKEW—The number of samples from when the speaker emits the signal source to when the FP35 microphone reads and analyzes it. See Section 2.5.1.5 for details. *OUTPUT SELECT—The external source devices enabled in the measurement screen.
162 FONIX FP35 Hearing Aid Analyzer 5.9 CROS, and BICROS When using the FP35 probe with a CROS or BICROS aid, we suggest the following setups and procedures. Four Goals: 5.9.1 5.9.2 5.9.3 5.9.
163 Real-Ear Measurements NOTE: Although the above two measurements calls for the FP35 to be UNLEVELED with the reference microphone OFF, the rest of the measurements in this section call for the FP35 to be LEVELED with the reference microphone ON. 5.9.2. Measuring the Overcoming of the Head-Baffle Effect This section describes how to measure how well the hearing aid overcomes the head-baffle effect. The methods are different for CROS hearing aids than they are for BICROS hearing aids. 5.9.2.
164 FONIX FP35 Hearing Aid Analyzer • Hearing aid in better ear, on, set at use gain • Transmitter on bad side turned off • Loudspeaker at 90º, 12 inches from bad ear Aided—Measurement of “better” ear canal (baffle overcome by aid) Same setup as above, except • Transmitter on bad side turned on The difference curve, labeled “Insertion Gain” on the screen, shows the benefit of adding the second microphone for sound arriving from the “bad” side. 5.9.
165 Real-Ear Measurements 5.9.3.
166 FONIX FP35 Hearing Aid Analyzer • Probe microphone inside unoccluded ear canal of good ear • Loudspeaker at 45º toward good ear, 12 inches from surface of head Aided—Occluded Response of “good” ear. Same setup as above, except • Earmold in place in good ear • Hearing aid is turned off GOOD EAR REFERENCE MIC BAD EAR PROBE MIC 12" SPEAKER The difference curve, labeled “Insertion Gain” on the screen, shows insertion loss, if any, caused by inserting the earmold into the good ear.
Chapter 6 167 2-CC Targets The 2-cc target screens allow you to 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.
168 FONIX FP35 Hearing Aid Analyzer The sections in this chapter will explain the following: • 6.1: Target creation • 6.2: Displays • 6.3: Measurements • 6.4: Reference 6.1 Target Creation In order to create a target for use in the Coupler Target screen or the Coupler EarSim screen, you must enter the Audiogram Entry screen, just as you would if you were creating a normal real-ear target. 1.
169 Target Coupler those controls will have no effect on your custom target. To re-enable the target controls, you must return to the Audiogram Entry screen and use the Generate Target key (F3) to recreate an automatic target. The NAL-NL1 targets in the Coupler Target screen have been slightly modified from the original NAL-NL1 formula in order to better represent low gain prescriptions.
170 FONIX FP35 Hearing Aid Analyzer 4. The signal and weighting types used with the selected curve. 5. N.R. = Noise reduction. 6. Status of reference microphone. 7. RMS/HFA data: If a composite signal is selected, the RMS OUT will be displayed here. Otherwise, the selected HFA or SPA will be displayed. Press [MENU] to select HFA/SPA frequencies. 8. Selected fitting rule. 9. Curve ID box. See Section 2.7.2 for more information. 10. Source Signal Statistics Box.
171 Target Coupler 6.2.2 Viewing the Coupler EarSim Screen The Coupler EarSim screen displays the actual real-ear target prescribed for the patient. Targets are shown in either real-ear SPL or insertion gain. When SPL is selected, the patient’s thresholds and uncomfortable levels are also displayed. Any coupler measurements taken in this screen are converted into simulated real-ear measurements using the average or measured real-ear unaided response.
172 FONIX FP35 Hearing Aid Analyzer 13. Curve ID box. See Section 2.7.2 for more information. 14. Source Signal Statistics Box. The information in the box is dependent upon signal type. • COMP, DIG SPCH—Displays the RMS source amplitude. • NORM, FAST, SHORT, LONG, SINGLE—Displays the source amplitude, frequency, distortion, and output/gain. Fig 6.2.2—Coupler EarSim screen displayed with simulated insertion gain 6.
173 Target Coupler 6.3.1 Taking Basic Measurements For your convenience, instructions for taking basic coupler measurements are given here: 1. Enter the Coupler Target or Coupler EarSim screen by pressing [F3] from the Opening screen and using the [NEXT] or [BACK] keys as necessary. 2. Press [MENU] from the measurement screen to make any necessary selections. See Section 6.4 for details. 3. Level the sound chamber as described in Section 3.2, if necessary. 4.
174 FONIX FP35 Hearing Aid Analyzer To view the target in numerical format: 1. Set the USER LEVEL to ADVANCED in the Default Settings menu. See Section 2.3.2 for details. 2. Press [MENU] from the Coupler Target or Coupler EarSim screen to enter the main menu. 3. Press [NEXT] to enter the Advanced menu. 4. Use [∧,∨] to select TABULATION. 5. Use [<, >] to select TARGET. 6. Use [EXIT] to return to the Target Coupler screen. The target data will now be displayed. See Figure 6.3.2. Figure 6.3.
175 Target Coupler 1. Press [MENU] from the Target Coupler screen to enter the local menu. 2. Press [BACK] to enter the Target menu. 3. Use [∧,∨] to select TARGET REF. 4. Use [<, >] to choose CURVE 1-4. A selection of AUTO will always tie the target to the current selected curve. 6.4 Reference The following is a description of the items available in the local menus of the Coupler Target and Coupler EarSim screens. The items in bold reference coupler targets specifically.
176 FONIX FP35 Hearing Aid Analyzer FIT TYPE—Type of fitting. Choose BILATERAL or UNILATERAL. This is only available with a fitting rule selection of NAL-NL1.TUBING. Note: If you select BILATERAL, you must enter the audiogram for both ears in the Audiogram Entry screen. AID TYPE—Style of hearing aid. Choose from BTE, ITE, ITC, and CIC. VENT—Type of venting on the hearing aid. Choose from OPEN, TIGHT, NO VENT, 1 mm, 2 mm, and 3 mm. This selection is only available with a fitting rule selection of NAL-NL1.
177 Target Coupler Advanced Menu Press [NEXT] from the main menu to reach the Advanced menu. *AUTO-SCALE—The type of scaling used. ON scales the graph to the selected curve. OFF scales the graph to the highest curve displayed. *TABULATION—Target data display on the right side of the Target Coupler screen. Choose TARGET or NONE. See Section 6.2.4 for details. *REFERENCE STATUS—The type of RMS measurement made with the reference microphone.
178 FONIX FP35 Hearing Aid Analyzer Custom Menu Press [NEXT] from the Advanced Menu to enter the Custom Menu. OUTPUT LIMIT—Level of output limiting, which shuts off the source when the measured signal exceeds the limit set here. Choices are: OFF; 80-140 dB SPL. This is usually used only for real-ear type measurements. *WARBLE SOURCE—The warble rate in pure-tone signals. Warble is usually used in sound field speaker measurements to reduce problems caused by standing waves.
179 Target Coupler *DISTORTION SWEEP—The frequencies used in the intermodulation distortion measurement. NORM uses 1/12 octave frequencies to the nearest 100 Hz. FAST uses 1/3 octave frequencies to the nearest 100 Hz. FULL uses every 100 Hz frequencies available. *DIST SWEEP END—The last frequency tested when performing an IM distortion sweep.
180 FONIX FP35 Hearing Aid Analyzer
Chapter 7 181 The Audiometer Option 7.1 Introduction The audiometer option on the FP35 turns your hearing aid analyzer into a type 5 screening audiometer. In other words, you can use the FP35 for doing puretone air conduction screening using either insert earphones or sound field testing. It is not intended for use as a clinical audiometer. 7.2 Equipment The audiometric testing is performed using either a sound field speaker or one or two insert earphones.
182 FONIX FP35 Hearing Aid Analyzer 6. Select ASSESSMENT and choose SPEAKER, using the arrow keys. 7. Select SOUND FIELD and use the arrow keys to choose 0º or 45º, depending up on the azimuth used in the client setup. 8. Select REF MIC (SPEAKER) and choose OFF, using the arrow keys. (The reference microphone will automatically be used for the leveling process, but you will probably not want to use it for the audiometric measurements.) 9. Press [EXIT]. 10.
183 The Audiometer Option 3. Place the reference microphone on a stand 1 meter from the sound field speaker. Position it at the head height of a seated listener. See Figure 7.3.1C. 4. Enter the Audiogram Entry screen by pressing [F2] in the Opening screen and using [NEXT] and [BACK] as necessary. 5. Press [MENU]. 6. Select EAR and choose the desired ear, using the arrow keys. 7. Select ASSESSMENT and choose SPEAKER, using the arrow keys. 8. Select SOUND FIELD and choose 0º, using the arrow keys. 9.
184 FONIX FP35 Hearing Aid Analyzer 7.3.2 Insert Earphones 1. Plug in the insert earphone (or insert earphone set) into the “earphone” jack on the back of your FP35 analyzer. 2. Insert the insert earphone (or insert earphone set) into your client’s ear(s). 3. Enter the Audiometric Entry Screen by pressing [F2] and using the [NEXT] and [BACK] keys as necessary. 4. Press [MENU]. 5. Select EAR and choose the desired ear with the arrow keys. 6. Select ASSESSMENT with [∨, ∧]. 7. Press [<, >] to select INS.
The Audiometer Option 185 Set up the client for testing as described in Section 7.3, but also use the earhook and insert a probe microphone in his or her ear. See Section 9.2.4 for more details. Now, follow the procedure described in the previous section. As you present a tone, the output in dB SPL is displayed under MIC SPL at the bottom of the screen. 7.4.3 Measurements in Gain To obtain measurement in dB Gain while performing audiometric measurements, follow the instructions in 7.4.
Chapter 8 187 Spectrum Analysis The FONIX FP35 can be used as a sound spectrum analyzer in either the coupler (test box) or Real-Ear Test Modes. External sounds are measured through the microphones and displayed in an amplitude-vs-frequency format. See Section 5.6 for instructions on live speech testing. 8.1 Spectrum Analysis Measurements Spectrum analysis measurements can be done in most measurement screens on the FP35 analyzer using the composite, digital speech, or fast pure-tone signals.
188 FONIX FP35 Hearing Aid Analyzer 8. While the “eee” is still sounding and once the curve on the screen has stabilized, press [START/STOP] again. Note the total RMS Output in the ear canal as indicated in the status box. 9. If the SPL seems high, you might modify the vent size. Then select AIDED 2 with [F2] and, if necessary, use [∨] to turn off the source. Repeat steps 7 and 8. You should see a change in the RMS Output. Aided Curve 2 should be less than Aided Curve 1. 10.
Spectrum Analysis 189 Synopsis: If you are doing a spectrum analysis of speech or room noise, leave the Spectrum Window ON in the custom menu of the Coupler Multicurve or the Target Coupler screen. If you are doing a spectrum analysis of a phase synchronous signal such as the source of a different analyzer, turn the Spectrum Window OFF in that menu.
Appendix A 191 Specifications ACOUSTICAL DRIVE SIGNAL SINE COMPOSITE Frequencies 200 to 8000 Hz 1/12 oct, nearest vals 100 Hz intervals 200 to 8000 Hz in 100 Hz inter- Frequency accuracy 1 percent 1 percent Frequency control Left-right buttons not applicable Amplitude(RMS) Chamber 40 – 110 dB SPL 40 – 110 dB SPL Amplitude(RMS) Sound Field (5 dB steps) 40 – 90 dB SPL 40 – 90 dB SPL Amplitude accuracy 2.5 dB: 500 Hz – 3.5 kHz, otherwise 3.
192 if source off: if source warbled: Pure tone, Real-Ear Mode if source >=85dB: if source <85dB: if source off: if source warbled: FONIX FP35 Hearing Aid Analyzer Graph filtered, current status estimated RMS Always filtered to fundamental frequency Estimated RMS* Filtered to fundamental frequency Graph filtered, current status estimated RMS Always filtered to fundamental frequency *Notes: Estimated RMS combines the energy at all frequencies from 200 – 8000Hz.
193 Specifications Reading Percent with respect to fundamental. Readings made at frequencies from 400 through 2500 Hz. INPUT POWER Voltage 90 – 250 VAC Frequency 47 – 63 Hz Power dissipation 27 watts typical with full operation. 23 watts when unit is in standby.
194 FONIX FP35 Hearing Aid Analyzer Function keys 5 function keys on front panel directly below LCD display. Function of individual button is described on LCD screen. Basic push button controls Print/Feed, Reset, Operate, Exit, Next, Back, Menu, Help, Start/Stop, ∧(ampl), ∨(ampl), <(freq), >(freq), LEDs Steady green indicates unit is operating; flashing green indicates it is in standby or screen-saver mode; red indicates a fault condition; alternating red and green occurs during software upload.
Appendix B 195 Software Upgrades As new features and options become available on the FP35 analyzer, you may want to upgrade your instrument. The FP35 analyzer is upgraded using computer software. It is recommended that you close any open programs on your computer before executing the software upgrade. It is particularly important to close any other programs that are Frye programs. It is also recommended that you disable your screensaver. To update your FP35 analyzer 1.
196 FONIX FP35 Hearing Aid Analyzer • The lower right corner of the screen displays instrument information. If you want to display information currently on the connected analyzer, click Check Instrument. If you want to display information about the update package that will be installed, click on the instrument file located just to the left of the Check Instrument/Update Flash/Make Diskette buttons.
Software Upgrades 197 To rebuild a corrupted CFG file Sometimes the instrument configuration file name can be damaged. This can happen if the package was copied through a computer system or program that does not understand long file names. If the name does not look right, or the Status says that the selected CFG file is not valid, try clicking on the Rebuild CFG button just above and to the left of the software CFG file selection. Normally that will correct a corrupted CFG file.
Appendix C 199 Calibration The FP35 provides you with a means to calibrate the system, the probe and coupler microphones, and the insert earphone(s). The system calibration of the FP35 should be done once a year, but the microphones should be calibrated only when necessary. Even if you have determined that the microphones are out of calibration, you should contact the factory or your sales representative before calibrating the microphones.
200 FONIX FP35 Hearing Aid Analyzer Coupler Microphone For the coupler microphone, you will need a sound level calibrator such as the Quest QC-10. 1. Press [F3] to enter the Coupler Multicurve Mode from the Opening Screen. 2. Use [F4] to choose NORM. 3. Press [MENU]. 4. Set REF MIC to OFF, if necessary, using the arrow keys 5. Press [NEXT] to enter the Advanced Menu. Set STATIC TONE to SINGLE. 6. Press [EXIT] to return to the Coupler Multicurve Screen. 7.
201 Calibration 11. Look at the response. This curve represents the difference between the probe response and the reference response. The maximum deviation from the zero line should be 5 dB. 12. If there is more than a 5 dB deviation from the zero line at any point along the curve, the probe microphone is out of calibration. C. Calibrating the Microphones To enter the Microphone Calibration Screen: 1. Press [MENU] from Opening Screen 2. Press [F3] to enter Calibration Screen 3.
202 FONIX FP35 Hearing Aid Analyzer 3. Close the sound chamber. 4. Press [START/STOP]. 5. When the calibration is complete, press [EXIT] to return to the Microphone Calibration Screen. D. Storing the Microphone Calibration 1. Press [F5] in the Microphone Calibration Screen. 2. Press [START/STOP]. E. Insert Earphone Calibration Before you can perform RECD or audiometric measurements, it is necessary to calibrate the insert earphone(s) that you will be using.
203 Calibration RECD coupler measurement 1. Set up your insert earphone for calibration as described above. 2. Select “Cal Left (Single) Ins. Earphone (RECD)” with [∧, ∨]. 3. Press [START/STOP] twice to perform the calibration. 4. If you are using only one insert earphone for the RECD measurements, skip to step 8. If you are using two insert earphones (one per ear), proceed to the next step. 5. Set up the right insert earphone as described above. 6. Use [∨] to select “Cal Right Ins. Earphone (RECD).” 7.
204 FONIX FP35 Hearing Aid Analyzer Calibrating the audiometer 1. Set up the left insert earphone for calibration as described above. 2. Select “Cal Left (Single) Ins. Earphone” using [∧] if necessary. 3. Press [START/STOP] twice to perform the calibration. 4. If you’re only using one earphone, skip to step 8. Otherwise, proceed. 5. Set up the right insert earphone for calibration as described above. 6. Use [∨] to select “Cal Right Ins. Earphone.” 7. Press [START/STOP] twice to perform the calibration. 8.
Appendix D 205 Fitting Formula Tables The conversions used by the FP35 to convert audiograms to target gain curves are the following. NAL-RP Fitting Formula Calculation The insertion gains at each frequency are calculated according to the following formulas: Freq (Hz) Insertion Gain (dB) 250 500 750 1000 1500 2000 3000 4000 6000 8000 X X X X X X X X X X + + + + + + + + + + .31 .31 .31 .31 .31 .31 .31 .31 .31 .
206 FONIX FP35 Hearing Aid Analyzer POGO Prescription of Gain/Output (POGO) for Hearing Aids by Geary A. McCandless, PhD, & Poul Erik Lyregaard, MSc Hearing Instruments vol 34 #1, 1983 Required insertion gain is calculated as follows: Frequency (Hz) 250 500 750* 1000 1500* 2000 3000 4000 6000* 8000* Insertion Gain (dB) 1/2 1/2 1/2 1/2 1/2 1/2 1/2 1/2 1/2 1/2 HTL - 10 dB HTL - 5 dB HTL - 2.
207 Fitting Formula Tables 1/3, 1/2, 2/3 Gain The 1/3-2/3 Insertion Gain Hearing Aid Selection Guide by Robert Libby Hearing Instruments vol 37 #3, 1986 Required insertion gain is calculated as follows: FREQ.
Appendix E SPL Conversions The Target IG is converted to the Target SPL in the following steps. 1. Add the source level for aided curve 2. 2. Interpolate from 10 frequency to 80 frequency curve frame. 3. Add the AVG unaided ear response REUR in Table 1. 4. If aided 2 is composite, subtract 10.7 dB from each frequency. 5. If aided 2 is speech weighted, subtract the speech weighting in Table 2. The complete formula is then: Target SPL = Target IG + CRV2 source + AVG REUR (If Aided2 is composite) - 10.
210 FONIX FP35 Hearing Aid Analyzer TABLE 1 Average Real-Ear Unaided Response (REUR) (Except for DSL and NAL-NL1) FREQ (Hz) GAIN dB FREQ (Hz) GAIN dB FREQ (Hz) GAIN dB FREQ (Hz) GAIN dB 200 300 400 500 600 700 800 900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 1.6 2.1 2.7 2.9 2.9 3.1 3.3 3.6 3.4 3.1 3.6 4.2 4.4 5.6 7.0 8.1 9.3 10.9 12.6 2100 2200 2300 2400 2500 2600 2700 2800 2900 3000 3100 3200 3300 3400 3500 3600 3700 3800 3900 4000 13.9 14.7 15.1 15.0 15.1 15.0 14.6 14.1 13.6 13.
211 SPL Conversions TABLE 3 HL to SPL (or SPL to HL) conversion table (Except for DSL and NAL-NL1) from ANSI S3.6-1989 Table G.1 FREQ (Hz) 250 500 750 1000 1500 2000 3000 4000 6000 8000 dB 19.0 12.0 10.5 9.0 12.0 15.0 15.5 13.0 13.0 14.
Appendix F 213 Digital Speech Technical Details The digital speech signal on the FP35 analyzer works by turning the composite signal on for a set period of time, taking a measurement, turning the signal off for a random period of time, and turning the signal back on again. This sequence is repeated until the user ends the test. Usually, either the ANSI S3.42 or the ICRA speech weighting is used to take the measurements. The signal “on” time takes a minimum of 50 milliseconds.
214 FONIX FP35 Hearing Aid Analyzer Figure F-1 Figure F-2
215 Index Index A A-LTASS 39, 143 Accessories 6–11 Adapter ear-level 6 earphone calibration 11 microphone 7 probe calibration 8 Adaptive 34 AGC 34, 97 AGC SWITCHING 99 Age 28, 130, 159, 177 Aided Response 132, 134 Aid Group 28, 88, 130, 159, 178 AID LIMITING 177 Aid Limiting 130, 160 AID TYPE 29, 131, 177 Aid Type 33 ANSI 39, 93, 98 ANSI 03 93, 96 ANSI 92 39 ANSI 96 96, 98, 100 ANSI TEST 96, 99 ASSESSMENT 30 Assessment 130, 182, 183, 184 Audiogram Entry Screen 3, 27, 30, 37, 111, 119 Audiometer Option 13,
216 E EAR 31, 99, 130, 159 Ear-Level Adapter 6 Earhook 8, 10 Earphone jack 4 EarSim 169, 171, 173 EQ INPUT NOISE 31, 99, 103, 107 ERMS 44 EXIT 3, 23 Extension Pole 8, 78, 113 External monitor 9, 13, 27 External Sound Source 188 External Speaker 47, 112, 114 F F1-F5 Keys.
217 Index Local Variables 22 LONG SETTLE 89, 100, 104, 108, 161, 179 Long Settle time 33 LTASS 39 M Maintenance 16 Medical Device Directive 5 MENU 3 Menu 20, 21, 23 MICROPHONES 90, 180 Microphones 7 reversing 82 splitting 83 Microphone Adapter 7 Monitor 9, 13, 27 MZ 62, 75, 76 N NAL-NL1 121, 158 Navigation 19, 111 New Client 129 NEXT 3 NOISE RED 29, 88, 99, 103, 107, 130, 159, 178 Noise Reduction 36, 43 NORM 34, 35 O Occlusion Effect 147, 187 OES Option 75 Opening Screen 17, 24 Open fit 139 OPERATE 4 OU
218 Sound Chamber 5, 12, 47 SOUND FIELD 130, 159, 182, 183 Sound Field Speaker 113, 116, 181 SPEAKER 32, 131, 161 Speaker Jack 5 Specifications 191 SPECTRUM WINDOW 90, 180 Spectrum Window 189 Speech-Weighting 142 SPL 184 Splitting Microphones 83 SPL Conversions 209 SPL screen 140 SPL Test 141 Standard 34 START/STOP 3 STATIC TONE 160 Swing Arm 9 T TABULATION 153, 160, 176, 178 Target 119, 120 modifying 122 Target Coupler screen 169 Target Data 153, 175 Target Formulas 142 TARGET REF 143, 159, 176, 177 TELEC
