we can say that hearing aids are an essential device for people who are hard of hearing. But sometimes if it is not enough then?
In some situation, people with an affluence of ambient noise, require an extra boost. Places like restaurants, great classroom setting or places with poor acoustics can easily expose the shortcoming of hearing aids in these situations assistive listening devices are used. ALDs are helpful to bring the sound closer to the ear. It does not only improve the ratio of speech to noise, but it can also separate the noise to be heard from the unwanted background noise. It is actually improve listening experience of hearing aid users.
Research says that people who have hard of hearing require a volume of 15 to 20 DB in order to achieve the same level of normal hearing. An ALDs allow it to achieve this gain for themselves without making it loud for everyone.
There are a number of ALDs are in the market, all of which have their distinct advantage in the different situation that helps to make hearing aids more effective. Here are some of the most popular ALDs we are going to discuss.
- Personal amplifier-
it is a small box with a mic and a listening cord attached to it. This ALDs device is mostly used for one to one conversation. It allows the person you are speaking with to attach the mic to there clothing so you can plug it into your personal amplifier and hear more clearly. It cuts out the most of the background noise. And there is also one advantage that it is relatively inexpensive and only of around $200.
The disadvantage of this device is that it cannot be useful in the situations when you required moving around a lot, because it has a wired connection with the speaker. But such as in concerts or theaters, which required mobility or hearing from a distance, are need more flexible systems.
- FM Systems-
A FM system is a wireless system that transmits the sound directly from the sound source to the receiver. An FM system can be used with hearing aids or cochlear implant, on the ear alone, or as a sound field system. This ALDs overcomes the limitation of personal amplifiers as it allows mobility in addition to hearing a more distant sound. FM system used radio broadcast function which brings sound directly to the ear. It is the wireless device that makes it portable which facilitate in hearing the speaker. The speaker has to wear a microphone transmitter, which allows listening up to 150 feet away. This ALDS is suitable for classroom or outside setting as it allows mobility at will and still able to hear the distant sound clearly. But you have to pay the added amount for this added flexibility, which costs up to $700 to $1000 on an average.
- The infrared systems-
An infrared system is similar to a remote control and a television. It transmits sounds using light waves. Since the light waves do not pass through walls, they are useful for situations in which privacy is needed doctor’s offices and court proceedings etc. Though they are often used for watching TV or in theaters, they have one major disadvantage that an object comes between the listener and the emitter causes the signal to be blocked. And also this system can’t be used in an environment with too many light source such as in sunlight or strongly lit room. Thus making this system suitable for some situations, and not as versatile as FM System.
- Induction loop systems-
An induction loop systems transmit an audio signal directly into a hearing aid that used an electromagnetic magnetic field. In this system, loop wire is used to create a special zone inside a building. A loop of insulated wire which can range from a small loop worn around the neck to a loop that encircles an entire room is connected to a power source, an amplifier, and a microphone. Loop systems are inexpensive as well as versatile, useful for a singlet-coil hearing aid user or a group. The listener must be wearing receiver and stay in the loop, to pick the signal. As the sound is directly picked up by a receiver, it is very clear, free from the background noise associated with many listening environments.
Bluetooth technology is the latest innovation for the hearing aids user. But Bluetooth hearing aids are not yet available, the technology allows two devices such as a cell phone or computer, and a wireless hearing aids with a compatible streamer to talk to each other. The range is limited, somewhere around 20 feet, but the lack of interference and secure connection of this convenient hands-free technology are outweighed and negatives. In addition, the use of one streamer can allow the user to switch back and forth among multiple devices.