Why Assistive Listening Systems Are Needed
Digital hearing aids are not a panacea
In many environments, even the best digital hearing aid is not enough for the hard of hearing to understand what is being said.
The hard of hearing find it very difficult to separate the background noise from the wanted signal. Digital filtering techniques and directional' steerable microphone technology can help, but fundamentally, the noise and wanted signal will contain the same frequencies and may also have the apparent same position of origin.
To overcome these issues the intelligible sound needs to be somehow physically isolated from the noise sources. This is easily achieved with recorded material, but for live speech it is a big problem.
In a crowded noisy bar we will get close to the person we want to talk to and probably speak directly into their ear to be heard above the background ambient. Assistive listening systems employ the same strategy. A microphone is positioned as close to the person speaking as possible meaning only their voice is picked up. The output is processed, amplified and delivered directly into the listener's ear.
There are several competing audio Assistive listening technologies- Induction Loops, Infrared Systems, FM Systems and Personal FM (wireless systems)
'Induction loop systems are the preferred assistive listening technology of the hard of hearing.They are the easiest to manage in a facility and over the lifetime of the system represent the lowest cost solution.'
At the first international conference on Loops and T-coils held in Switzerland Sept 2009, 98% of the delegates voted in favour for a motion in support of T-coils and induction loops.
The following is an extract from the conference courtesy of the European Federation for the Hard of Hearing,
An audio frequency induction loop system (AFILS) is an inexpensive, efficient and universal system to enable people wearing hearing aids or cochlear implants to hear in public situations.
We recommend that:
1) hearing aid manufacturers, manufacturers of cochlear implants, physicians, audiologists and hearing instrument specialists shall communicate the benefits of hearing aid / cochlear implant telecoil receivers for phone listening and assistive listening and educate people who are hard of hearing accordingly.
2) venues and service points where sound is broadcast shall offer assistive listening, such as induction loop systems designed to the IEC 60118-4:2006 standard, that broadcast sound directly to hearing aids and cochlear implants, enabling them to serve as customized, wireless loudspeakers (without the need for extra equipment).
For more information visit www.efhoh.org