FONIX® FA-10 Hearing Evaluator™ - Frye Electronics

Large Vent Simulation for Ski-slope Losses
For “ski-slope” hearing losses, you will likely be using a very large vent, where low frequencies
are allowed to pass unamplified into the ear canal, while only the high frequencies are
amplified. The flexible design of the FA-10 lets you simulate a large-vent fitting in the following
way:
1. You will use one audiometer channel to feed unamplified sound (50 dB HL) to the test
ear and the other audiometer channel to amplify only the high frequencies. You must
use a single sound source, fed through both audiometer channels, to the same ear. External
sources (e.g., tape or CD) can be used for this purpose with all FA-10s. To use live
voice, you must have either the optional gooseneck microphones or the optional boom
microphone/headset. Do not use the built-in panel mics for this purpose. The possible setups
are:
• A single external input (tape/CD) channel. For example, to feed the left tape or CD
channel to the left ear, use the following settings:
Left Input to “External”
Left Output to “Phone”
Right Input to “Left External”
Right Output to “Left Channel”
• The gooseneck microphones. The two microphones must be placed directly side-byside
or head-to-head, with the sound inlets as close as possible to each other, even
touching. (Hint: Remove the foam wind screens first, but be sure to place the microphones
lower than mouth level, to avoid amplifying breath noises.) Use the following
settings:
Both Inputs to “Mic.”
Output of the test-ear side to “Phone.”
Output of the non-test-ear side to the opposite channel.
• The boom microphone/headset. Use the following settings:
Both Inputs to “Mic.”
Output of the test-ear side to “Phone.”
Output of the non-test-ear side to the opposite channel.
2. On the non-test-ear side, set the Hearing Aid Simulator to “Off” and set the Hearing
Level to 50 dB HL. This passes the low and mid frequencies to the test ear, unamplified.
3. On the test-ear side, set the Hearing Aid Simulator to “HFE.”
4. Set the Hearing Level dial of the test-ear side to 30 dB HL.
5. While presenting speech materials through both channels, gradually raise the Hearing
Level of the test-ear-side only, until maximum clarity is achieved. This adjustment
changes the level of the high frequencies, while maintaining a constant SPL for the lower
frequencies, as Figure 5.2.1 on the next page illustrates.
Frye Electronics FONIX FA-10 Hearing Evaluator 41