A Comparison of Loop, FM & IR Technologies For Assistive Listening
Posted by: Russell Gentner – President, Listen Technologies on
Jan 05, 2012
There are many options for assistive listening technologies. This blog post provides a comparison between the three technologies used in assistive listening.
There’s been a lot of discussion about Hearing Loop technology for use in assistive listening. The recent New York Times article “A Hearing Aid That Cuts Out All The Clatter”
points to the many benefits of using induction loops in theaters, places of worship and other venues. Thus, the purpose of this blog is to provide a comparison between the three technologies used in assistive listening.
RF (Radio) Technology
- This uses the same technology used by a radio station or a two-way radio to wirelessly deliver audio to your ears using an RF receiver
. The system uses a small transmitter with an antenna to cover an entire theater or stadium.
IR (Infrared) Technology
- This uses infrared light (yes, the same IR technology as in your TV remote control) to transmit audio to your ears using an IR receiver
. These systems uses IR radiators (it’s like a headlight on a car) to flood IR light into the facility. Most facilities require about four radiators to be installed throughout the venue.
Induction (Loop) Technology
- Hearing Loop technology uses a magnetic field to wirelessly transmit audio to your ears using either a "T-Coil equipped" hearing aid with a built in “T” switch
or or, with a Hearing Loop receiver with earphones. These systems use a wire, or flat copper tape of loop(s) that are typically installed on the floor of the entire venue. The added install cost is the reason that hearing loop systems can potentially cost more than RF or IR system, especially in retrofit installations.
If you’re like 10% of the population and you struggle to hear, assistive listening systems like these can dramatically improve your ability to enjoy the content delivered by the venue. All three of these technologies offer this advantage whether you have a hearing aid or not.
The “Magic” Of Loop Systems
Now, if you do have a T-Coil or, TeleCoil equipped hearing aid and it has a “T” switch
, a hearing loop system makes it very simple to use. You simply walk into the venue, set your “T” switch
and presto you hear audio right in your ears. You don’t need a receiver or earphones. It’s magic! This is why hearing loop systems have such a wide appeal for people who have “T” switch
In North America, many people who have hearing aids don’t have a T-Coil or, TeleCoil equipped hearing aid with a “T” switch
where as in Europe most hearing aid users do have a “T” switch
. My hearing aid does NOT have a “T” switch
, and thus, no matter what type of technology a facility might have, I have to request a receiver and earphones to hear the audio. Maybe my next hearing aid will have a “T” switch
(NOTE: When this article was originally written the percentage of Tele-Coil equipped hearing aids in the U.S. were fairly low, but now most hearing aid manufacturers are offering this technology and the percentages are increasing)
Thus, the “magic” of a hearing loop system can only be enjoyed by those individuals who have a hearing aid with a “T” switch
. Everyone else must use a Hearing Loop receiver and earphones. The fact is that the majority of people who are hearing impaired do not even own a hearing aid.
Advantages Of RF And IR Systems
RF and IR technology assistive listening systems offer two main advantages:
1. Low cost
2. Ability to deliver multiple audio sources.
The cost of a typical RF system is less than $5,000 and the cost of an IR system is less than $10,000 for an average venue. Haering Loop systems can potentially cost much more. The lower cost of RF and IR is because the building does not need to be modified to be installed. In Hearing Loop systems, (depending upon the design) the loop must be installed over the entire floor of the venue and it must be carefully designed and installed to ensure complete coverage and no interference to equipment within the facility.
Additionally RF and IR systems can also be used for multiple audio sources. For example, at the Kennedy Center
they use their IR system not only for assistive listening but they also use it for audio description and audio instruction.
If a person does have “T” switch
or, "T-Coil equipped" hearing aid, they can still use an RF or IR system to connect directly to their hearing aid. This is done by plugging a neck loop into an IR or RF receiver (it’s worn around the neck). The neck loop inductively connects to the hearing aid.
It is great to hear the enthusiasm and the interest in Hearing Loop systems for assistive listening. Hearing Loop systems offer a great convenience and “magic” factor people with “T” switch
hearing aids. And no matter what technology a venue chooses, anyone can use and benefit from the system.
When you consider 10% of the population is hearing impaired (just like me…) it’s important that we have the ability to enjoy a play or enjoy the music.
This chart offers a side by side comparison of some of the considerations for each type of technology.
||Induction Loop Technology
|Can be used with a hearing aid that has a "T" switch without ANY other equipment
|Can be used with a hearing aid that has a "T" switch but requires a neck loop plugged in to an FM or IR receiver
|Relative convenience level for individuals with a hearing aid that has a "T" switch
| Relative convenience level for individuals with a hearing aid that DON'T have a "T" switch
|Relative cost of installation for a new building
|Can be used for applications beyond assistive listening such as audio description, language interpretation, etc.
|Maximum number of simultaneous channels
|Secure. Signal does not travel outside the room
|Relative audio quality
||Medium / High
|May interfere with equipment within the facility (such as a mixing console)
||Yes / Possible
(* The NY Times article was reference a onetime event that had a temporary loop system installed)