Frye FONIX 7000 - Manual (Page 164)

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FONIX 7000 Hearing Aid Analyzer
6.4.12 Using Output Limiting
When performing real-ear measurements, it is very important not to expose
your client to noises that could conceivably further damage his hearing. For
this reason, the 7000 test system has built-in output limiting. When the probe
microphone reads a value above the output limit at any frequency, the test will
automatically stop.
The default setting for the output limit is 120 dB SPL. In the real-ear measure-
ment menu, you can change this limit to any value between 90 dB SPL to 140
dB SPL in 5 dB steps.
Be aware that extra care is necessary with any output that may exceed 132 dB
SPL. Also, keep in mind that the sound pressure level at the eardrum can be
higher than that measured at the mid-ear canal position, especially at high fre-
quencies. For this reason, extreme caution is advised when performing real-ear
measurements with a source level of 90 dB SPL.
To change the output limit:
1. Press [MENU] to enter the real-ear measurement menu.
2. Press [∨, ∧] to select Output Limit under Measurements.
3. Use [<, >] to choose the desired limit.
4. Press [EXIT] to return to the real-ear measurement screen.
6.4.13 Measuring the occlusion effect
You can use the Insertion Gain screen in order to measure the “occlusion effect”
of a hearing aid. By analyzing the spectrum of your client’s own voice, you can
judge whether the occlusion effect will make the hearing aid uncomfortable,
and you can measure an improvement (lessening) of the occlusion effect after
adjusting the vent opening.
To measure the occlusion effect:
1. Enter the Real-Ear Navigation screen by pressing [F2] from the Opening
screen.
2. Follow the instructions in Section 6.2.3 to insert the probe tube into the cli-
ent’s ear. You do not have to level the sound field speaker for this measure-
ment.
3. Insert the hearing aid in the client’s ear, being careful not the move the
probe tube. The hearing aid can be turned on or off.
4. Enter the Insertion Gain screen by pressing [F3] from the Real-Ear
Navigation screen.
5. Use [F2] to select the REUR 1 curve. (Press [F2]. Use [∨, ∧] to select REUR 1.
Press [>] to complete the selection and close the pop-up menu.)
6. Use [F5] to select a source type of COMPOSITE.