Hearing and hard of hearing listeners benefit from their use. However, the type of microphone and its placement at the sound source is crucial for the ALS to be effective. FM Systems- Sound, via microphone or public address system, is fed into an FM transmitter. It sends sound to small, individual FM receivers. FM systems produce an excellent sound quality.
Users have freedom to choose their own seating locations.
The systems are not subject to electrical interference and are highly portable, simple and inexpensive to install. Maintenance and operating costs are low because the systems are highly reliable. Also, several frequencies are available. It transmits through walls so adjacent rooms should be equipped with other frequencies to avoid interference. The receiver is equipped with an amplifier so that the sound level can be controlled by the user.