Assistive Listening - Other
The purpose of an assistive listening system is to send audio directly to the listeners, either through a headphone/earpiece, or perhaps directly to their hearing aid, so that reverberations and background noise do not make the sound unintelligible. There are 4 main types of assistive listening systems:
Conventional FM
Digital FM
Infrared
Inductive Loop
Here are the pros and cons of each:
Conventional FM: Pros - FM systems are easy to install and use, relatively inexpensive, and flexible in that they work for people with or without hearing aids.
Cons - If you have multiple adjacent rooms - such as a multiplex movie theater, or a court building - each room may need to be on a different channel. They cannot provide 'absolute guaranteed secrecy' which may be needed in a courtroom, or other government or high-security locations.
Wi-fi: Pros - A wi-fi system can send a signal to the smartphone or tablet of each user, so they don't need to have a specialized receiver. This could obviously be a large cost savings.
Cons - Your wi-fi system needs to be very robust, and meet stringent system requirements. You may need a knowledgeable IT person to handle the installation. Other wi-fi traffic may seriously impact the audio quality. There are limits as to how many listeners you can have on the system, depending on the specifications of your wi-fi system. There could be logistical issues such as you may need to provide power outlets so listeners can keep their phones charged. You may also need to keep a supply of earpieces in case people forget to bring theirs. The technology is still quite young, and so may change more often than the more established technologies.
Digital FM: Pros - These newer systems - Digi-Wave being the best known brand - offer 2 way communication. So they are great for classrooms. The frequencies used are often legal in many countries. These systems can accommodate up to 15 languages.
Cons - older digital systems had a fairly short range, but the newer ones (such as Digi-Wave 400 series) have a very good range. Digital systems are usually more expensive than conventional FM systems.
Infrared: Pros - IR systems can have total security, which makes them great for courtrooms and top-secret events. They can also be used in multiplex movie theaters, where all the theaters can be on the same channel, with no signals straying from one theater to another.
Cons - generally more expensive than conventional FM systems. They have a much smaller range than FM systems, and may require skilled installation. Some IR systems are not very portable.
Inductive Loop: Pros - With an inductive loop system, listeners who have a T-coil switch on their hearing aids can pick up the audio without any additional device.
Cons - Inductive loop systems are best installed when the building is under construction. Retrofitting is harder. Installation requires s specialist technician.
