Assistive Listening Devices (ALD)

Q. What are assistive listening devices?
A. Assistive Listening Devices (ALDs) are amplification instruments that are designed to be helpful in specific, but not all listening situations. For instance, there are ALDs that amplify the TV, that amplify the telephone, that amplify in theaters, that amplify in places of worship, and that amplify public speakers. Hearing aids, which also amplify sound, are instruments that can be used in all listening situations. But because a hearing aid is an all-purpose instrument, it may not be as successful in each and every specific application.

Q. How do ALD’s differ from hearing aids?
A. The construction of an ALD is different from a hearing aid in one important aspect. All of the components of a hearing aid, the microphone, the amplifier, and the loudspeaker are located within the body of the instrument that is placed on the user's ear. Therefore, the microphone of a hearing aid picks up both signal and noise. In contrast, the microphone of an ALD is separated from the body of the instrument and is placed at the sound source so that it is most apt to pick up the desired signal at the expense of background noise. In practice, the ability to selectively amplify signal, but not background noise, is the biggest advantage of ALDs.

Q. When should you consider using an ALD?
A. An ALD should be considered when you have difficulty in a specific, but not all situations. For instance, if you like the TV louder than your family, an infrared, FM, or loop system would allow you to solve this problem. A microphone is placed in front of the TV loudspeaker (attached with Velcro). The microphone is connected to the transmitter. Your family would adjust the loudness of the TV to their comfort, you would adjust the loudness of your receiver to your comfort. In this way, the specific problem of TV viewing is solved. If you have difficulty in a number of different situations, you should consider a hearing aid instead of an ALD. You also may use an ALD with your hearing aid to enhance the performance of the hearing aid. If you are having difficulty hearing in a specific situation ask us what is available in an ALD system that may help you.

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Duncan Hearing Healthcare

1822 North Main Street - Suite 201
Sagamore Complex
Fall River, MA 02720
Phone: (508) 674-3334