Category : Articles
FM Advantage Demonstrations
Frequency Modulation (FM) is a wireless communication technology commonly used in the classroom to overcome the adverse effects of distance and competing noise in communication situations. Using an FM system in difficult listening situations makes communication easier because regardless of the distance between the teacher and the student, the signal is delivered directly to the FM receiver at a consistent volume level.
Personal worn FM systems are assistive hearing devices that can be used by hearing impaired children. They benefit only the single child using the personal device, by picking up the teacher??™s voice and directing it into the ear of the hearing impaired child. They filter out the background noise. This is helpful and a necessary learning aid for the hearing impaired child, but it does not benefit the other children in the class. It also only amplifies the teacher??™s voice, not the voices of the other students in the room. Therefore, the hearing impaired child cannot hear or learn from the other students talking in the room. Sound enhancement systems used in addition to personal FM assistive technology allows the hearing impaired child to hear other the students and the teacher, including the hearing impaired child as part of the class discussion.
The primary benefit is in the even distribution of the teacher??™s voice, not the amplification of the teacher??™s voice. In fact, sound enhancement systems allow the teacher to use a conversational tone, because he/she doesn??™t have to be concerned with projecting their voice to the back of the room. A teacher can actually speak in a softer more nurturing voice, which is more conducive to learning. The speaker??™s voice is more clear, crisp and understandable regardless of the physical position of teacher and the student.
FM Systems use radio frequencies to send sound from a transmitter to a receiver. They work like small radio stations. FM systems transmit sound via radio waves (frequency modulation) from the speakers microphone to the listeners portable receiver.
For people who use cochlear implants, the FM receiver transmits the speaker??™s voice directly to the recipient??™s sound processor.
Both the transmitter and receiver must be tuned to the same channel. Receivers will capture the signal of the closest transmitter using the matching channel, rejecting other weaker signals.
The speaker, such as a teacher, presenter, or parent wears a microphone, which is connected to the transmitter. The hearing impaired person wears the receiver which can be connected to a variety of listening devices such as headphones, a neck loop, or sometimes directly to a hearing aid. For hearing aids that are equipped with a T-switch, a neck loop creates an electronic magnetic field between the receiver and the hearing aid, and the FM system can be used without headphones.
On some models an environmental microphone can be added to an FM system. This allows the user to hear other people in the environment besides the speaker who is equipped with the main microphone. For example, if you are listening to a lecture and someone in the audience asks a question, the environmental microphone will enable you to hear the person in the audience and then you can switch back to hear the speaker.
FM Systems can accommodate a full range of listening options. Patient??™s can use listening options with hearing aids, cochlear implants or without hearing aids. The FM accessories available provides a full range of listening options including neck loops and silhouettes that are made for people with severe to profound hearing loss.
Hearing aids perform best in quiet environments or when you are sitting close to the person you want to hear. Using an FM system (with or without hearing aids) makes it easier to hear in noisy environments or when you are sitting a distance away from the person you want to hear. Using hearing aids with an FM system can be compared to using bifocals. When you wear glasses with bifocals, you can see up-close and also at a distance. When you wear hearing aids and use an FM system, you can hear up-close and also at a distance.
The environmental microphone option is most useful for classroom situations that include group discussion. It allows the user to have access to 2 microphones. One microphone is on the transmitter with the instructor and the other one is on the receiver to pick up sounds around the student. Although environmental awareness is still desirable, the signal arriving via the FM system must still be the dominant one.
Those with hearing aids equipped with a telecoil can use a telecoil coupler. They are ideal for classroom and meeting use and work well both indoors and outdoors. If multiple FM systems are used near each other, separate broadcast frequencies should be used, as FM signals are not limited to line of sight and can penetrate walls and ceilings.
Wherever a large PA system is impractical or where audio needs to be amplified for people to hear better, a soundfield works well. Soundfields are not just beneficial to individuals who are hard of hearing, they can help in any situation where audio needs to be amplified for people to hear better, no matter if they wear hearing aids or not. Best known in the education industry, soundfields are also suitable for conference rooms, training centers, theaters, places of worship, courtrooms, convention centers and ballrooms, even cruise ships and tour buses.
In the past, FM systems were only used in schools. They helped students listen in noisy and reverberant classrooms.
Today, FM can be used in many everyday listening situations. Some typical daily situations include:
* Talking with someone in a social situation: At home, work, on a busy street, at a shopping center or in a restaurant.
* Group conversations: At a family get together, in a very noisy restaurant, at business meetings or conferences.
* Making telephone calls: on home, cellular or cordless phones.
* Watching TV and listening to music.
* Schools and further education: In classes at schools and universities, on outings and excursions, in lectures, or on museum tours.
* Transportation: In cars, trains, trams and buses.
* Sports: When cycling, playing golf, skiing, jogging or hiking.
* Events: At a theater, in concerts, at the movies, in church services, or at community meetings.
A comprehensive knowledge and understanding of microphone vs. microphone + FM use and application is imperative in a future professional capacity in order to educate clients, as well as to know how to best serve their individual needs in specific situations. For example, an understanding of acoustics that we deal with in our everyday lives such as in the classroom, are invaluable especially when trying to help a child succeed. Classrooms are auditory-verbal environments where 60% ??“ 70% of learning is through what the teacher vocalizes. If a child hears distorted speech, he will develop distorted speech production. This, in turn, will lead to poor language skills resulting in poor reading skills. Without proper reading skills children end up with poor academic performance. There is a broad range of potential psychosocial and physical difficulties that comes with hearing impairment; therefore professional intervention cannot be limited to hearing aids. Many times, hearing aids by themselves will not be enough to restore effective communication. However, if used in conjunction with other assisstive listening technologies, communication strategies, and auditory rehabilitation, communication can be improved, allowing for a better quality of life.