Hearing in the classroom
Classrooms, notorious for their high levels of ambient noise, make for very poor listening environments for all students and particularly for those students who are cochlear implant users. Therefore, it is essential that these students be provided with an amplification system such as a personal FM (frequency modulation) system and/or a classroom sound-field/audio system. Such systems amplify and enhance the instructor’s voice, allowing it to be adequately heard above the sounds of the other students voices and movements, heating and cooling system noises, and the reverberations caused by furniture and school supplies being shuffled around the classroom.
A classroom audio system consists of a microphone and transmitter, worn or held by the instructor, a receiver which captures the voice of the instructor, an Audio Amplifier (in which the receiver is generally located) and which processes the sound and serves as a control base, and a speaker system which delivers the amplified voice of the instructor to all the students in the classroom. Such a system benefits not only the hearing impaired students in the classroom, but also those students with normal hearing as well as students with attention-deficit issues. A personal FM system consists of a transmitter and microphone worn by the instructor and a receiver worn by the student. The instructor’s voice is delivered directly to the student’s speech processor so the signal is pure and undistorted in any way.
Ideally, and particularly for the very young CI user student, a personal FM system is the system of choice as it delivers the instructor’s voice directly to the student’s processor and can thus provides the best signal to noise (S/N) ratio. Typically, a classroom sound-field FM system improves a classrooms S/N ratio by about 10 dB to 15 dB. A personal FM will provide the student using it with a significant improvement in S/N ratio of a 20 dB to 30 dB gain. The CI user student can also use a personal FM in a classroom equipped with a classroom sound-field system; the personal FM system’s transmitter can be patched into the Audio Amplifier of the sound-field system, allowing the instructor the need to wear only one microphone even though two systems are in use.