FONIX® FA-10 Hearing Evaluator™ - Frye Electronics

5 .2 Complete Instructions for Using the Hearing Aid Simulator
There are many methods for fitting hearing aids. The choice of method is up to the individual
fitter. The instructions below are merely suggestions on how to use the Hearing Aid
Simulator; they are given as a guide to selecting gain, frequency response, and maximum
output. The suggested procedures can give the operator a starting point toward a final hearing
aid selection.
5 .2 .1 Selecting Gain and Frequency Response
Coarse MCL Estimate
The first step is to make a coarse estimate of the client’s Most Comfortable Level (MCL) for
speech.
• Set the channel Input for “Mic” if you are going to use Monitored Live Voice, or “External”
if you are going to use recorded materials.
• Set the channel Output for “Phone.”
• Adjust the Mic or External level control so that speech will be presented at 0 VU.
• Use the “Off” setting of the Hearing Aid Simulator.*
• While presenting speech materials or monitored live voice (as close as possible to
0 VU), raise and lower the “Hearing Level” dial until the client indicates that the
speech is at a comfortable hearing level, not too loud, not too soft. There may be a
range of levels that satisfy this requirement. Choose the lowest level that is comfortable
for the client to listen to without straining.
Choosing a Slope and Final MCL
(Note: For “ski-slope” losses, use the separate procedure, below.)
Once you have established a “coarse MCL” setting, try changing the Hearing Aid Simulator
setting to other slopes, while asking the client to judge the sound quality and intelligibility. The
goal here is to find the setting with the best balance between “clarity” and “pleasantness.”
If the client indicates that one slope setting sounds louder or softer than another, adjust the
Hearing Level dial to achieve MCL at each setting you try.
Make a note of the final hearing level and slope settings.
* When the audiogram slopes notably downward between 250 Hz and 1000 Hz, consider using the “ 6dB” setting.
This will cause the perceived loudness at “coarse MCL” to be closer to that obtained with the final slope setting.
NOTE WELL: The “MCL” obtained with anything but a flat slope (“Off” setting) is not standard, and therefore
should not be entered as “MCL” on an audiogram sheet without indicating the divergence from standard practice.
Frye Electronics FONIX FA-10 Hearing Evaluator 39