Induction loop systems are a means of conveying audio directly into a hearing aid user's hearing aid.
This direct transfer of audio, directly into the user's hearing aid, is important for a number of reasons. A person without a hearing impairment only needs a few decibels of difference between background noise and whatever it is they are trying to listen too, for the human brain to distinguish between the two. People with hearing impairments generally need significantly greater "signal to noise ratio" for the brain to separate the background noise from the subject noise.
The great problem with most hearing aids is that they amplify everything by the same amount, meaning that background noise is amplified as much as the subject noise. This makes noises louder, but does not help the hearing impaired person from being able to discriminate between noise and subject sound.
Most hearing aids feature a built in microphone, which picks up the ambient noise, which is then amplified directly into the users' ear canal. This is generally called the "M" position. Usefully, to assist primarily with listening to telephones, most hearing aids have a separate setting called the "T" position. This was originally designed to pick up the magnetic field of the speaker in the earpiece of a phone. As this speaker generates sound, its magnetic field changes, and this can be detected in the Telecoil of a suitable hearing aid. This magnetic field is changed back to useful sound, and amplified into the users' ear canal.
This "T" position greatly enhances signal to noise ratio, but only for "audio" received magnetically.
This is where induction loop steps in, or, to give its proper title, Audio Frequency Induction Loop Systems (AFILS). Through the use of an induction loop amplifier, sound destined for the hearing aid user is amplified into a loop of cable, rather than a traditional speaker. This loop generates a magnetic field, which the hearing aid user stands in. By switching there hearing aid to the "T" position, they only hear sound being fed into the induction loop amplifier, cutting down on background noise, and making comprehension of the audio far easier.
This obviously assists hearing aid users massively, as they only receive sound that has been deliberately made to be received by them, and with minimal background noise. However, if the microphone that is supplying the induction loop amplifier, with source sound, is also picking up lots of background noise, the system can be pointless, and no better than the user setting the hearing aid to the "M" position.
This is why it is important to choose an installation company that actually understands the point of induction loop systems, and the pitfalls that can occur. Systems that are no better to the user than their own "M" position, are, unfortunately, far too common, and ultimately a waste of money for all concerned.
