FM signals are not limited to line of sight and can penetrate walls and ceilings. Personal FM systems are commonly utilized with children who have bilateral hearing loss. Large Area FM Systems are used for group listening in auditoriums, theaters, places of worship, cinemas, etc. These systems have a transmitter that connects to the existing sound system. The program is broadcast throughout the listening area.
Students use a personal receiver and earphone or telecoil coupler to pick up the broadcast.
This allows the students to hear the program directly from the sound system and by-passes background noise and distance from the sound source. These products require specific installation and familiarity with sound system equipment. A large area FM might be seen in a school auditorium. This eliminates the need for wearing additional equipment and is more cosmetically appealing to older students and young adults. To be effective, the receiver must be within direct line of sight of the light beam from the transmitter.