Assistive listening devices (ALD) help people with hearing difficulties or partial deafness hear things more clearly, primarily through sound amplification and removing background noise. One of the first iterations of assistive listening devices was volume amplification on telephone devices in the late 19th century, as Alexander Graham Bell realized that some people could hear things more clearly over the telephone than they could in person due to volume.
Modern assistive listening devices now typically fall into three categories: public devices, private-use devices, and hearing aid amplification.
Public devices include FM systems and “loop systems” to directly connect a speaker’s microphone into the hearing aids of all who use them. Private-use devices include things like volume amplifiers on phones or amplified alarm clocks that ring extra loud to be more easily heard. Hearing aid amplification ALDs typically connect a public or private device directly into one’s hearing aid (like a loop system) versus amplifying sound at the source (like an amplified alarm clock).
Many personal assistive listening devices – particularly for volume amplification features – are now considered standard features on most pieces of technology like home phones, smart phones, or alarm clocks. It’s worth noting that these features are used by people with full hearing as well as those with hearing difficulty or partial deafness, since adjusting the volume is a comfort measure as much as it is an accessibility feature. Public devices typically require specialized technology and common brands include Widex and Signia.