FONIX 8000 Hearing Aid Test System

The FONIX 8000 is the world’s most advanced hearing aid test system, featuring the unique Polar Plot Sound Chamber, capable of performing automatic polar plot measurements of directional hearing aids. Although the results are not a replacement for laboratory testing using an anechoic chamber, the 8120 Polar Plot chamber provides the hearing health professional with a clinical tool for verifying approximate directionality characteristics of the hearing aid. As directional hearing aids continue to grow in popularity, this feature has become essential in the modern hearing aid clinic.

Directional Testing

The Polar Plot Option on the FONIX 8000 Hearing Aid Test System includes two test screens for performing measurements on directional hearing aids: The Directional Polar Test Screen and the Directional Difference Test Screen.The revolutionary Polar Plot test screen gives the clinician a 360º view of the directionality of the hearing aid at the specified angles. The two-dimensional directionality index (2D/DI) is automatically calculated for each curve as well as the overall average 2D/DI for all eleven possible curves. These values will help the clinician quantify the directionality of the hearing aid.

A polar plot showing that hearing aid is amplifying sounds in front of the patient at higher levels than sounds behind the patient will confirm to the clinician that the directional hearing aid is functioning properly. However, a completely circular polar graph will immediately tell the clinician that the hearing aid’s directionality is not working at all.

Also available is the Directional Difference test screen. The Directional Difference test displays a more conventional frequency graph that showed the difference between the hearing aid’s “front” response and its “back” response. This tells the clinician how the hearing aid’s directionality changes depending upon the frequency of the input signal.

 

How does it work?

In the 8120 Polar Plot chamber, the hearing aid is mounted on a rotating spindle in front of the sound chamber speaker. During the polar plot test, the FONIX 8000 Hearing Aid Test System automatically rotates the hearing aid in a 360 degree circle, taking measurements at angles specified by the user. Results are displayed in polar plot format on the test screen in either dB Gain or dB SPL.

Simultaneous Mode

In Simultaneous Mode, a composite signal is used during the polar plot measurement, and the results at five different frequencies are plotted simultaneously, providing fast but complete test results.

Manual & Program Modes

In Manual Mode, the user can choose from the Composite signal or any choice of puretone signals from 200-8000 Hz in 100 Hz intervals. Up to eleven different polar plot curves can be measured on the screen at one time. In Program Mode, the user can choose a sequence of up to eleven different polar plot measurements and run them all automatically.

ISTS Test

The ISTS test screen is part of a new way of performing coupler measurements on advanced digital hearing aids, representing a major departure from the traditional ANSI method of evaluating hearing aid performance.

The ISTS test is based upon the new IEC 60118-15: 2012 standard. Third octave analysis is performed on the hearing aid response to the standardized speech-like signal for a choice of 10, 20, or 45 seconds (actual test times are slightly longer). When the test is complete, the results are displayed as the long-term speech spectrum (LTASS), and the 30%, 65%, and 99% of the distribution of sound pressure level. Many of the top minds in the hearing health industry put their heads together to come up with this unique test!

Automated Test Sequences

The FONIX 8000 Hearing Aid Test System can be purchased with the ANSI S3.22 87/96/03, IEC 60118-7 94/05, JIS 2000, or a combination of these test sequences. This makes the 8000 Test System capable of testing hearing aids manufactured and sold in countries all over the world.

Alternately, you can build your own automated test sequence with the Auto Test feature available in the Coupler Multicurve screen. Using Auto Test, you can program the source type and level of up to ten different frequency response curves. You can even add pauses to the test sequence to give you time to adjust the hearing aid in between measurements. Three different custom sequences are available for each user. These tests can be loaded automatically, creating a one-button test sequence that is fully customizable for the needs of the clinic.

Enhanced DSP

Enhanced DSP is an innovative test unique to the FONIX line of hearing aid analyzers. It tests the signal processing delay and the phase of the digital hearing aids.

Signal processing delay is the time it takes for the hearing aid to process sound through its circuits. In a monaural or open fitting, unaided sound can reach the ear faster than it can travel through the hearing aid, potentially causing localization problems or “echoing” effects. In some cases, the digital signal processing delay of the hearing aid can be up to 15 ms, although more commonly it is in the range of 3-6 ms.

Phase is a measurement of how the hearing aid pushes and pulls sound through the receiver of the hearing aid. For a pair of aids in a binaural set to be working properly together, both aids must be “pushing” and “pulling” in the same manner. If the phase test shows opposite graphs, it’s possible that one of the components inside the hearing aid was wired backwards, decreasing the fidelity of the total signal. The phase test gives you the ability to quickly determine if the hearing aids are working together as a team.

Testing Digital Hearing Aids

The FONIX 8000 Hearing Aid Test System comes equipped with the Digital Speech signal. This is a modulated broadband signal for testing digital hearing aids. Many digital hearing aids have noise suppression technology. When part of the input signal is constant (such as a conventional test signal), the hearing aid does not amplify it as much as the part of the input signal that is modulated, such as a speech signal. The modulation in the Digital Speech signal typically causes the hearing aid to amplify the signal instead of suppressing it.

As an additional feature, the Digital Speech signal has the option of adding a Bias Tone. The Bias Tone creates a continuous signal at a selected frequency. This allows the user to determine how the hearing aid reacts in the presence of noise at various frequencies. This can also show the behavior of the hearing aid in channels where the noise is not present. If there is noise at 500 Hz, does the hearing aid suppress the signal at 4000 Hz? The Bias Tone can tell you exactly what’s going on when part of the test signal contains a continuous input.

Real-ear Measurements

The FONIX 8000 Hearing Aid Test System can be purchased with the Real-ear Option. Verify your hearing aid fitting with single or dual probe microphone measurements to ensure that you are providing your patient with the amplification most appropriate for his or her hearing loss. Hearing aid fitting software can only show you approximations of the actual amplification provided by the hearing aid. Use real-ear measurements to make sure that the hearing aid is performing as expected.

Visible Speech is particularly useful in demonstrating to your patient how the hearing aid amplifies actual live or pre-recorded speech. The FONIX 8000 features exceptionally fast measurements so that you can see the response to even short duration signals such as fast-changing consonants in speech.

The Real-ear Option also includes the FONIX NOAH Real-ear Module, providing a Windows-based interface to the FONIX 8000. This great computer program includes the DSL 5, NAL-NL1, and MOD NAL fitting formulas.

Advanced Testing

High end users such as researchers and hearing aid manufacturers often need to be able to perform specific coupler measurements that are usually included as part of an automated test sequence. For those users, the FONIX 8000 has the Input/Output, Attack & Release, and Battery Current test screens.

In the Input/Output test screen, you can measure the compression characteristics of the hearing aid at any frequency between 200 and 8000 Hz in 100 Hz intervals. Alternately, you can choose to use the broadband Composite signal.

In the Attack & Release test screen, you can measure the attack and release compression characteristics of the hearing aid and display the results as a function of time in graphical format. You can even zoom in on the test results to get more detailed information about how the hearing aid reacts to sudden increases and decreases in the test signal.

The Battery Current test screen gives the user an estimate of the battery life of the hearing aid and performs battery current measurements as a function of frequency and input level so you can see if the hearing aid drains the battery more in certain situations. This gives you a very complete picture of the battery current drain of the hearing aid.

8050 Mid-Sized Sound Chamber

The 8050 Mid-Sized Sound Chamber is available for the FONIX 8000 Hearing Aid Test System. It is compact and attractive yet large enough to provide good sound isolation with minimal sound reflections. The speaker is mounted vertically at the back of the chamber, making it easy to position the hearing aid with respect to the speaker. All cables required for normal testing with the 8000 Hearing Aid Test System including the microphone, battery pill, and a Hi-Pro pass-through are connected inside the chamber, so there are no leaks in the seals when the lid is closed.

Note: The Mid-Sized Chamber does not have polar plot measurement capability.

Exterior Size: 11.5″W x 13.5″D x 9.2″H

Weight: 21.8 lbs

Test Area Size: 5″W x 6″D x 1.5″H

Ambient Noise Isolation: 45 dB at 1 kHz

Note: Specifications can be found in 8000 Operator’s manual

Note: The FONIX 7000 cannot be upgraded to the 8000.