Frye FONIX 7000 - Manual (Page 71)

Basic Sound Chamber Tests
63
We have also developed a non-standard coupler for open-ear hearing aids. It has
two design purposes: 1) To make an convenient connection between the hearing
aid and the coupler, and 2) To provide a more real-ear like frequency response
than is possible with an HA-1 or HA-2 coupler. Figure 3.3.4C shows a picture of
the open-ear coupler with an attached hearing aid.
Figure 3.3.4A—HA-2 Coupler Figure 3.3.4B—HA-1 Coupler
Figure 3.3.4C—Open-ear coupler
Figure 3.3.4D contains an example of a comparison of an open-ear hearing aid
tested with an open-ear coupler (Curve 1), an HA-1 coupler attached to the
open-ear hearing aid with Fun-Tak (Curve 2), and an HA-2 coupler with an
open-ear attachment (Curve 3). The dark line (Curve 4) in the graph represents
the KEMAR real-ear gain response of the hearing aid. As illustrated, the open-
ear coupler provides the measurement most like the real-ear response of the
hearing aid.