Assistive Listening Devices have proven to be an effective teaching tool for students with hearing loss. Providing a good listening environment can have a major impact on an individual s academic performance. ALDs utilize different technologies. Typically, they are wireless or wired. Wireless ALDs make use of radio frequencies, light rays, or magnetic inductive energy to transmit sound.
Hardwired ones use direct electrical connection to transmit the auditory signal.
Each system has special features, capabilities, advantages, and disadvantages. FM, Soundfield Amplification, and Induction Loop Systems will be discussed. An FM system is a wireless, portable battery-operated device that uses radio transmission to send auditory signals, i.e. speech, from a transmitter to a receiver. With most FM systems, the instructor wears a lavelier microphone connected to a body-worn transmitter. The FM receiver can also be connected to the student s hearing aid via an induction neckloop system or direct audio input cables.