Frequency response characteristics of FM mini-loop auditory trainers.

Personally sized inductance loops (mini-loops) now are available for use with an FM classroom amplification system and the student's personal ear-level hearing aid. Frequency response characteristics of five commercially-available hearing aids were assessed 1) using hearing aid test equipment available in most audiology clinics, with the hearing aid on microphone setting and 2) in a public school classroom, with the hearing aid on telecoil setting and operating with an FM mini-loop system. Clinic and classroom characteristics of the conventional FM receiver-insert earphone auditory trainers also were assessed. Results showed that the personal hearing aids' classroom performance could not be predicted from their clinic performance. Results also showed that gain provided by the environmental microphone circuit of the FM receiver-insert earphone units was uniformly higher than that provided by the teacher-microphone signal route.