Some cars more noisy than others
Drivers with hearing aids may benefit greatly from using a tele-coil, or T-coil, when driving their cars. In normal conditions, hearing impaired people can use the T-coil to listen to the radio, receive information from their GPS or speak on their mobile phone in the car without interference from the considerable background noise stemming from the car and traffic.
But a Danish test found that many new car models are so loaded with electronics that the T-coil is overpowered by the electro-magnetic noise from the high-tech components.
Test the noise levels in your car
Car buyers with hearing loss should be aware of these issues when shopping for a new car. Fortunately, it is easy to determine whether or not a car is well suited for T-coil users. Just take a seat in the car, start the engine and activate the T-coil as you would when driving.
In a T-coil friendly car all you will experience is a gentle and insignificant whoosh in your ears. If you hear annoying interference from electrical sources, you should look for another car. When testing the car's T-coil suitability, make sure you turn on the window wipers, the fan and other potential noise-makers.
Source: Motor and FDM 2008