FM SYSTEM
ASSISTIVE LISTENING DEVICES
What is an FM System?
An FM system improves the transmission of sound, thereby making speech more accessible to the person
using it. The speaker wears a lapel or neck loop microphone and transmitter about the size of a cell phone.
The other person has a similar-sized receiver and wears a headset or ear bud or plugs the wire from the
receiver into a hearing aid. An FM system is similar to an FM radio station that "broadcasts” the
speaker’s voice to a listener's FM receiver.
How FM Systems can Help
FM systems improve the "signal-to-noise" ratio, so it sounds as if the speaker is standing next to
the listener’s ear. The clarity of the signal and the amount of information received varies according
to the ability to process information. If the listener has a hearing loss, the degree of loss also
affects the amount of information received. The listener may need to have a clear view of the speaker's
mouth, if he/she reads lips.
Hearing aids do not filter out background noise; they amplify all sound equally, which is fatiguing
for the listener. The FM system filters out background noise, which enhances the strength and clarity
of the listener’s signal. The improvement in sound quality can be quite pronounced.
HOW TO USE THE FM SYSTEM IN THE CLASSROOM
- The student is responsible for bringing the equipment to class and managing it. Ask the speaker
to position the lapel or neck loop microphone 3-5” from the mouth.
- Perform a listening check each time the FM System is used. Always have spare batteries
available.
- Ask the instructor to face the person with the receiver and to speak clearly in a normal tone of
voice. Do not over-enunciate.
- During class discussions, the instructor should allow only one person to speak at a time and pass
the transmitting microphone to each speaker. If that is not feasible, the instructor should repeat
the speaker’s comments and/or questions before responding to the class.
- For small groups, such as seminar classes, the student can borrow a conference microphone from
DSS that is placed in the middle of the table.