Phonak All about FM
Restricted access to auditory information in the educational setting can occur when
- the teacher’s voice is of low intensity
(e.g., the student is not seated near the teacher)
- it is masked-over by a non-target auditory signal
(e.g., classroom noise is louder than the teacher’s voice creating a poor signal-to-noise ratio)
- it is interfered with by reverberant (i.e., “echoing”) speech energy
Students with hearing loss are at a particular disadvantage when listening in such classroom environments because the ability of individuals with hearing impairment to recognize speech is more negatively affected by poor signal-to-noise ratio and high reverberation time, as compared to normal-hearing listeners.
Although children with hearing impairment are typically fitted with personal amplification, hearing instruments alone are often not enough to help these students understand their teacher in a noisy and reverberant classroom. In addition, hearing instruments alone cannot overcome the negative effects of listening in an environment where the distance between a teacher and a student is not always constant or predictable. For these children, the negative effects of noise, distance, and reverberation are best addressed by the use of an FM system.
Classroom Sound examples (Hearing instrument alone and FM alone)