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140 FONIX FP35 Hearing Aid Analyzer
5. Measure the aided response as described in Section 5.4.2.
• Thesourceamplitudeshouldbesetto65dBSPL.Usetheup-downarrow
keys to adjust the source if necessary.
• [F4]shouldbesettoDIGSPCH.
6. Press [START/STOP] to start the measurement. Press [START/STOP] again
when the measurement has stabilized.
7. Look at the difference between AIDED 1 and AIDED 2.
If there is no more than 2 dB of difference between AIDED 1 and AIDED 2 at
any frequency, you can perform real-ear measurements using that particular
model of open ear hearing aid without adjusting the hearing aid analyzer. If the
two measurements are different by 3 dB or greater at any frequency, it is recom-
mended to disable the reference microphone when performing REMs using this
type of device. To disable the reference microphone, follow the instructions
found in Step 4 above.
When performing a real-ear measurement while the reference microphone is
disabled, it is particularly important to make sure the patient doesn’t move after
the sound field speaker has been leveled because the reference microphone will
not be able to compensate for any changes in the patient’s position.
5.5 The Real-Ear SPL Screen
The SPL screen permits the user to view all the major components of a client’s
hearing loss and hearing aid fitting on one screen in dB SPL. The hearing
thresholds and uncomfortable loudness levels, which are generally measured
in HL, are converted to SPL. The insertion gain target is also converted to SPL.
You can measure and display the unaided response and three aided responses,
in SPL, at three different source amplitude levels. Having all this information
in a common format provides a convenient way to view the hearing loss and
the amplification provided by the hearing aid without the confusion of different
frames of reference.
The factory default amplitudes used in this program are generally 50, 65 and 90
dB. (When DSL is the selected fitting rule, these default levels will vary.) The
user may choose other amplitude levels while conducting the tests. The idea is
to make sure that:
•Softsoundsareaudible(AIDED1).
•Moderatesoundsarecomfortable(AIDED2).
•Loudsoundsdonotexceedtheuser’suncomfortableloudnesslevel
(AIDED 3).
This technique is especially appropriate for non-linear hearing aids.