Portland State University. Department of Speech Communication
Thomas G. Dolan
Date of Award
Master of Science (M.S.) in Speech Communication
1 online resource (97 p.)
This study examined the frequency response characteristics of three behind-the-ear hearing aids alone and in combination with three FM auditory trainers. The hearing aids and FM auditory trainers were coupled using two different methods: direct audio input and personal mini-loop. Also, two different gain control settings were used. Frequency responses were evaluated using a template method specified in ANSI S3.22 1982 standards. A larger percentage of the personal mini-loop combinations failed to meet this ANSI standard as compared to the direct audio input combinations (72.3% vs. 50%). The frequency response curves for various combinations of hearing aids and FM auditory trainers were also separated into high and low frequency bands. Significant changes in output were found for the low frequency region, and these changes were dependent upon the coupling method. Specifically, the personal mini-loop tended to produce a significant reduction in output in the low frequency band as compared to that of the hearing aid alone. The use of direct audio input resulted in a significant increase in output in the low frequency band as compared to that of the hearing aid alone. This latter method produced the best overall agreement with the hearing aid frequency response, especially when the FM auditory trainer was set at full on gain and the hearing aid at a low gain setting.
Morrison, Robert Bruce, "Frequency responses of hearing aids coupled with FM auditory trainers" (1989). Dissertations and Theses. Paper 3913.