Attaching a Coupler to an
Open-Ear Hearing Aid

“Open-ear” style hearing aids have boomed in popularity over the past couple of years. Unfortunately, the ANSI standards have not yet caught up with them. At the moment, there is no standardized method of performing a coupler measurement on an open-ear style hearing aid. Hearing aid manufacturers have independently developed different mechanisms for attaching an open-ear hearing aid to an HA-1 or HA-2 coupler. One such device, pictured in Figure 1, is attached to the speaker unit of the open-ear hearing aid and to the tubing of an HA-2 coupler. Other connecting devices may consist of a plate that attaches to an HA-1 coupler.


Figure 1—HA-2 Coupler


To perform a coupler measurement to the ANSI S3.22 standard, we recommend using Fun-Tak to connect the speaker unit of the open-ear hearing aid to an HA-1 coupler, as pictured in Figure 2. We believe that the HA-1 coupler is better than the HA-2 coupler for open-ear hearing aids because, unlike the BTE aids for which the HA-2 was designed, open-ear hearing aids are not attached to an ear mold.


Figure 2—HA-1 Coupler


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 shows a picture of the open-ear coupler with an attached hearing aid.


Figure 3—Open-ear coupler


Figure 4 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.



Figure 4—Comparison of couplers with open-ear hearing aid.
   Curve 1 was measured using the Open Ear coupler,
   Curve 2 with an HA-1 coupler,
   Curve 3 with an HA-2 coupler, and
   Curve 4 is the KEMAR real-ear response.

Also see our new Open Fit Coupler