Monday, October 11, 2010

Using the Fine tuning graphics and sound features to investigate the potential in mind440 signal processing

This bulletin describes the graphics and sound features in Compass V4.5. The descriptions focus on the graphic and sound options in the different windows in the Fine tuning section of Compass. Please refer to Compass in order to see the details of the screen. Remember that Compass offers several help functions to explain the different options in the program: Tooltips, Using this window panels and the help manual. The Fine tuning graphics and sound options allow the user and hearing care professional to explore the sound processing capability of mind440. These tools can be used for visual and auditory evaluation and demonstration of the individual fitting, as well as for adjustment of the sound processing schemes in the hearing aid.


Fine tuning tools
In the Fine tuning window you have access to three basic tools – performance graphics with SoundTracker or static curves, LifeSounds MicroPlayer and the Program starter, which - used in combination - can be a powerful instrument in the follow-up process. The three tools are useful when evaluating the user’s subjective perception of the initial hearing aid fitting, when demonstrating the effect of further adjustments and when explaining recommended situational usage to the hearing aid user.

Graphics panel
The Graphics panel displays dynamic and static views of the hearing aid’s performance for the individual fitting. The type of view can be selected form the Graphics drop-down list in the Toptool bar.

SoundTracker
By default, the SoundTracker is activated, showing the real-time hearing aid performance for the current sound environment. Four different SoundTracker views are available, each presenting the hearing aid’s performance from a different perspective. The aided view is active by default. SoundTracker offers three alternative views: the unaided view, which clearly shows the fast dynamics of most input signals, the gain view, where the slow acting compression of mind440 is very evident, and the accumulated view, where an accumulated output spectrum as well as band specific and overall RMS levels of the output of mind440 can be produced. All the different SoundTracker views are available both in dBHL and dBSPL.

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SoundTracker shows the dynamic performance of the hearing aid
Static graphic options
If you prefer a static view, you can use the Graphics drop-down list in the Toptool bar to select one of the classic Widex performance graphs. Please be aware that all performance graphics are now available as either dB HL or dB SPL data. If no hearing aid is connected, the static graphics are available in simulated mode.
• Speech Spectra
• Insertion gain versus input
• Insertion gain versus frequency
• Input versus output
• Output versus frequency
In Compass V4.5 and above it is possible to view targets for the individual fitting in the Insertion gain versus frequency and Output versus frequency curves.

ISTS - International Speech Test Signal
The new graphic Insertion gain versus frequency uses an input signal called International Speech Test Signal (ISTS). ISTS is a new speech like test signal that reproduces the most important human speech characteristics relevant to the characterisation of hearing aids. This signal is intended to provide a satisfactory correlation between objective measurements and the real operation of hearing aids when processing speech in natural environments.
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The new graphic Insertion gain versus frequency is estimated with input of the ISTS signal

Program starter
If you have defined more than one program in the hearing aids, you can use the Program starter panel in the upper part of the window to shift between the different programs and let the user evaluate them one by one. The listening program highlighted in the Program starter panel will be the one the user listens to, and all parameters and graphics in the window will relate to that program. The Program starter also indicates the interdependency between the different listening programs. By default all additional programs are linked to the Master program, meaning that all fine tuning carried out in the Master program will also affect the other programs. For more information about the link features see the bulletin “How to fine tune non-master programs in mind440 fittings”.

LifeSounds MicroPlayer
If you have the Widex LifeSounds™ module installed, you have access to your Sound Library in the Toptool bar. Use the MicroPlayer drop-down list to select sound situations, and use the play button to play the selected sound. You can choose sound examples that suit your client’s lifestyle, or sound examples that are specifically targeted to the different listening programs. In this way, you can demonstrate and evaluate the different programs in realistic situations.

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