FM Listening Systems

Classroom Tool for Deaf and Hard of Hearing Children

FM Listening Systems are often used by deaf or hard of hearing children in the classroom setting. 

What is FM?

FM stands for frequency modulation and is a common form of radio transmission. FM is one of several wireless technologies that transmit sounds directly to a hard of hearing person.

FM listening systems let teachers talk into a hand-held microphone, which transmits the sound of the teacher's voice directly to a deaf or hard of hearing child's hearing aid.

This transmission happens on reserved radio spectrum 216-217 MHz. Many retailers of products for deaf and hard of hearing people carry personal FM systems.

Benefits of FM

FM provides improved listening clarity for people with hearing loss who have trouble when trying to understand speech, because of distance, reverberation and distracting background noise. FM aims to:

  •  Reduce distracting background noise

  •  Reduce reverberation and sound distortion

  •  Reduce listening fatigue

  •  Improve voice clarity and understanding

  •  Improve hearing at a distance from the speaker

How FM Technology Works

The FM transmitter's microphone picks up a speaker's words within inches of their mouth. Consequently, the sound that the listener hears (via their personal receiver) is free from attenuation (natural volume decay over distance), reverberation and distortion and, usually, background noise. The listener's headphones may also help to partially block additional background noise surrounding the listener.

 

This process is referred to as improving the ‘speech to noise ratio’ (SpNR) or 'signal to noise ratio' (SNR). Improving the SpNR is the most beneficial strategy available for improving speech comprehension for hard of hearing people.

Non-Hearing Impaired and FM Technology

FM technology also benefits the non-hearing impaired -- during tours, interactive exhibitions and language translation, for example.

All a non-​hearing impaired person needs  is a receiver and a set of headphones or ear buds.

Non-hearing impaired users will share the benefits of reduced background noise, reverberation, sound distortion and listening fatigue plus improved clarity and ease of listening at a distance.

Using FM in the Classroom

Here are some tips for teachers using FM listening systems:

  • Speak in a normal tone of voice with the microphone approximately 14 cm from your mouth. 
  • An FM system will usually transmit up to about 50 yards. The clarity of the signal and the amount of information received depend on the student's loss and ability to process the information heard. The student may need to have a clear view of the speaker's mouth to receive all of the information. 
  • For in-class discussions, pass the transmitter to the speaker or, if working in small groups place it in a central location such as the middle of the table.
  • Encourage the student to take responsibility for the daily charging of the equipment. Somone will need to check that it is in good working order each morning.
  • Keep a supply of batteries on hand. 
  • Ask your audiological technician or audiologist for a checklist to assist with troubleshooting the equipment. Keep it close to the area where the system is charged.
  • Be aware of the procedure for repair of equipment and check to see if there is a loan process while the malfunctioning equipment is out for repair.

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