“ALD’s” –  What They Are And How They Work


Assistive Listening Devices or ALD's help people with hearing loss who are able to wear hearing aids by bringing desired sound (known as "the signal") directly to the hearing aids of the listener.

Assistive Listening Devices or ALD’s help people with hearing loss who are able to wear hearing aids by bringing desired sound (known as “the signal”) directly to the hearing aids of the listener.

For most people with hearing loss who use hearing aids or cochlear implants, there is tremendous benefit. Often, however, certain conditions in our listening circumstances create difficulties that even very excellent hearing aids cannot adequately address. Such conditions might include background noise, the absence of visual cues, and distance between you, the listener, and the sound signal that you are trying to listen to and understand.  Additional devices known as Assistive Listening Devices (sometimes referred to as Hearing Assistive Technologies) have been found to be extremely beneficial tools for the person with hearing loss.


The Basics
The principle underlying the way that ALDs work lies in the concept of distance between the source of the sound signal and the listener with hearing loss.
• An ALD shortens the distance between the sound signal and the listener by delivering the signal directly to the listener. This elimination of distance has the effect of greatly reducing the problems that can be caused when sound travels through a distance, such as
?   weakening of sound energy, especially for high pitched consonants;
?   distortion, which inevitably happens, especially in spaces with lots of hard surfaces and high ceilings, when sound waves bounce off surfaces and continue over time.
?   distortion which inevitably happens when the environment includes unwanted noise.
• The shortened distance between the listener and the sound source, made possible by ALDs,  is achieved either through the placement of a microphone (transmitter) near the source of the desired sound signal, (e.g., the mouth of the speaker) or through direct electrical connection to the audio output component of your T.V., radio etc. That signal is directly delivered to your hearing aids, cochlear implant, or earphones.


Assistive Listening Device Support through HLAA Boston Chapter
Through the Hearing Assistive Technologies (HAT)  Program and in partnership with Gallaudet University, Hearing Loss Association of America makes available to its members training in the selection and use of assistive listening devices   Currently, two members of HLAA Boston Chapter, Carol Agate and Barbara Johnson, have  trained with the HAT Program and work with our members in learning about and adopting these important tools for successful communication.
If you would like help with adopting assistive technologies or would simply like to learn more about them, please contact us at and add “ALD Help” to the subject line.
Hearing Loops:  Readings and Resources
–> Sound Strategies
–>    Let’s Loop America’s Worship Centers, by David Myers
–>    How Hearing Loops Can Help, by Stefanie Weiss – Washington Post (April, 2009) 
–>  Why Loops Are the Preferred Listening System
 –> Telecoils and Loops  (An excellent blog post from Widex, Inc.)


Finding Assistive Listening Devices in Public Places:


Bluetooth:  Readings
–> Hearing Health and Technology – Wayne’s World.
Part I of a tutorial on Bluetooth technology and hearing aids
Part II
Part III


Buying new hearing aids?  What to look for:
–> on Bluetooth and telecoils in hearing aids, from Share the Sound: Let’s Loop Seattle


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