Using the FONIX 7000 to Verify Coupler and Real-Ear Performance ...

Real Ear Measurements 53
Figure 69 – Spectrum analysis of a HA with feedback as characterized by
instability in spectrum analysis and peak at approximately 3000 and 6000
Hz). The clinician can also use the earphones and amplifier (volume control
knob) delivered with the Frye 7000 and placed in the probe module to listen
for an “echo” and the presence of feedback. Often the perceived presence of
the echo is an “early sign” of the feedback and is the beginning of the change
of the waveform during this spectrum analysis .
Figure 70 – spectrum analysis of hearing aid with audible “whistling” feedback.
It’s interesting to note that a difference as little as 1 dB can change a measure as
seen in Figure 67 to the one seen in this Figure!