by Neil Bauman, Ph.D.
A man wrote:
I just bought the MaxIT bluetooth neckloop and recently tried it in my 2003 Honda Odyssey van. The electrical interference from the engine was so loud that I couldn’t use it. As the engine went faster the sound got louder.
I then tried the MaxIT in my 1996 Toyota Rav 4 with no problem, as least at idle. Otherwise it has worked fine. As you probably know, the use of the device in the car is important to eliminate background noise while riding in the car. Thanks for any help you can provide.
What you are hearing is mostly ignition noise caused by the spark plugs firing. Unfortunately some vehicles are electrically “quiet” and others are very “noisy” as you just discovered.
About 30 years ago when I was an active radio amateur, we “hams” had to cope with the same interference to our mobile radios. Fortunately, we knew a few tricks that largely eliminated it. You can do the same. (You’d think they would do this in all modern cars, wouldn’t you?)
The first thing to do to eliminate this interference is to replace the spark plug wires with special high-resistance spark plug wires. That was often the primary fix. Also, we’d put a capacitor across the alternator and that fixed the alternator “hash”. A good garage mechanic with a specialty in electrical stuff should be able to eliminate, or at least greatly reduce, this interference to an acceptable level.
I’ve heard from numerous people who want to use their t-coils in their cars—and to their dismay, their cars produce a lot of interference. Incidentally, don’t blame the neckloop. It isn’t picking up the interference. It’s the t-coils in your hearing doing that. You just notice it when you are using assistive devices such as the MaxIT neckloop because otherwise you have your aids in microphone mode.
Magnetic interference is one thing all hard of hearing people should take into consideration when buying a car. Sit in the car, start the motor and with your hearing aids in t-coil mode see whether you can hear any interference and if so, how bad it is. If it is too noisy, look for another car, or you could have a bargaining point to have the dealership correct the problem (at no extra cost) before you buy the car.
Silicon spark cables for the engine were made to avoid that interference. Maybe your car is using copper spark cables; in that case, you could buy some silicon cables to solve the problem. If you look carefully to the any spark cable, you must see the writing “copper” or “silicon”.
Good Luck
I’ve heard of magnetic interference but I didn’t realize what all could cause it. Interesting article.