Hearing aids are the best all-around solution for people with hearing loss, but other assistive listening devices (ALDs) can help you navigate specific communication demands. A frequency-modulated (FM) system is an ALD that makes it easier for people with hearing loss to hear what others are saying in noisy environments, like a theater, school, church, museum or other public places. This wireless system, also called a personal FM system, uses radio waves to deliver speech signals directly from the speaker's mouth to the listener's ears.
Components of an FM system
A personal frequency modulation (FM) system uses radio waves to send speech and other signals to hearing aids. FM is the same type of signal as your FM radio, only it’s tuned to a frequency band designated for personal use. There are two basic components of a personal FM system: a transmitter microphone and a receiver. The receiver may be integrated into a pair of hearing aids or a set of headphones.
Microphones for FM systems
The person speaking, like a teacher, friend or family member, wears the microphone portion of the FM system. This microphone encodes their voice into a frequency-modulated signal. There are several types of microphones that may be used:
- Lapel microphone: The most common type of microphone, a lapel microphone hangs around a person's neck like a lanyard or should be clipped to a person's shirt at chest level. It should be within about six inches from the speaker's mouth to pick up the strongest speech signal possible.
- Boom microphone: This microphone hangs off the ear so the microphone is positioned about 3 inches away from the face. A boom microphone is the sort of style a pop singer or customer service representative would wear.
- Table-top microphone: As you might expect, table-top microphones are placed in the center of a table in order to pick up all the voices at the table instead of a single voice. These are suited for conference rooms or quiet restaurants.
Receivers for FM systems
The person with hearing loss wears the receiver portion of an FM system. The receiver picks up the low-power radio signals transmitted by the microphone. The range of personal FM transmission is around 50 feet. Often, the receiver is integrated into the wearer's hearing aids or cochlear implant, and the signal is delivered directly through the hearing devices. Like microphones, there are several different receiver types:
- Ear level receivers: Often referred to as a "hearing aid boot," these receivers attach directly to BTE hearing aids or cochlear implants. This is the most integrated solution for individuals who wear hearing aids. Children with hearing loss wear these receivers in school.
- Neckloop receiver: This type of receiver, also called an induction loop, is worn around the neck and transmits the signal to your hearing aids via electromagnetic energy. This receiver requires the use of telecoil in your hearing aids.
- Body-worn receiver: Body-worn receivers can be slipped into a pocket or clipped to a waistband. Although bulkier, they are portable. Paired with traditional headphones, they are a perfect solution for someone who does not wear hearing aids, or is temporarily without hearing aids during a repair. Physicians often use this type of receiver to talk with elderly patients who have hearing loss but don't wear hearing aids.
Benefits of FM systems
People with hearing loss often struggle with clearly understanding speech in loud environments, even though their hearing aids are working overtime to pick out the speech signal in the presence of the background noise. To give your hearing aids a break and reduce your mental fatigue, you might consider purchasing an FM system for use when going out to restaurants, parties or other large gatherings. There are many benefits of FM systems.
FM systems reduce background noise, improve clarity and reduce listener fatigue.
Reduced background noise
People with hearing loss, and even those without, often have trouble hearing in situations when background noise gets in the way. FM systems reduce this noise and only amplify the voice of the speaker you are trying to hear.
By receiving the signal of interest directly to your ears or your hearing aids, the sounds will be much clearer than if they had to travel through a loud environment to get to you. It's like having your conversation partner speak directly into your ear, without the hot breath in your face. It's this crisper signal of an FM system that can make it preferable in a movie theater--without the FM system to control the overall volume, the movie might actually be too loud for you to understand.
Hearing from a distance
If you enjoy going to lectures or speeches, FM systems can be a great way to ensure that you are hearing every word that the person in front of you is saying. For example, if you are going to a graduation ceremony and your grandchild is speaking on behalf of her class, you don't want to miss it. Having your grandchild wear a compatible microphone will ensure that your FM receiver can reproduce the signal clearly for you, even in a large auditorium.
Just like any part of the body, if you are trying too hard to hear, you will suffer from mental fatigue. In fact, one of the symptoms of hearing loss is a feeling of exhaustion after spending a few hours in conversation. FM systems amplify speech signals in challenging environments so that you have the energy you need to do the activities you want to do.
FM systems in public settings
There is no reason to let your hearing loss stop you from enjoying the theater or going to the movies. Many large auditoriums have the capabilities to provide excellent sound quality without interference.
FM technology in a theater setting allows you to use your hearing aid with an FM receiver, and the signal goes straight through to the device so that the sound is clear. For those who don't wear hearing aids, FM systems paired with traditional headsets may be available for you to wear during the show. Don't be shy--ask at the box office.
FM systems for children
Children who are experiencing hearing loss may struggle with being able to hear properly in the classroom. This can hinder their education and cause them to lag behind because they cannot understand what the teacher is telling them. Some classrooms use a sound-field amplification system so that all children may benefit from an amplification of the teacher's voice. A sound-field amplification system uses a microphone to amplify the speaker's voice through a loudspeaker system that is positioned strategically in the classroom. This way all students can benefit from the amplification, and those with hearing loss are freed from the burden of wearing a special receiver.
An FM system is especially important for children with hearing loss as they attend school. It ensures that these children receive consistent speech signals even when they aren't looking at the teacher or when the teacher is moving around. A microphone can also be passed around to other students as they participate in a lesson so that the child with hearing loss has an opportunity to hear those comments and questions as well. An FM system at home gives children with hearing loss a better opportunity to interact during daily activities with their families and better enjoy trips to the zoo, park or in the car.
Purchasing FM systems
FM systems can be purchased online, in electronics stores and through your local hearing healthcare professional. If you don't know how to get started or what device might work best for you, talk to your practitioner, and ask for a demonstration. If you don't wear hearing aids but struggle to hear in many common listening environments, it may be time for a hearing test!