by Neil Bauman, Ph.D.
A lady asked,
Have you ever dealt with the problem of noise (buzzing) from fluorescent lights in a loop system? I’ve heard that you can buy special ‘ballasts’ for the lights that will take care of that. Is that right?
Here’s the deal. Back about 1998 or so, a bunch of fluorescent light ballasts were imported into the USA that were basically junk and caused a lot of interference which was picked up by the t-coils in hearing aids. Most of these defective ballasts have since been replaced so interference from bad ballasts is not all that common now, but it still happens. (Occasionally, ballasts can go “bad”.)
Modern ballasts shouldn’t cause any interference. For example, I have a 4 tube fluorescent light fixture right above my desk in my office, but the ballast causes such minimal interference that my fancy field strength meter’s t-coil has to be within 9″ of the ballast before I even reach the ideal minimum noise (interference) level as specified in the International loop standards.
This means that you could have the top of your head bumping the light tubes and you still shouldn’t hear any buzzing in your hearing aids from these lights. That’s how little interference modern florescent light fixtures really cause.
If you turn on any fluorescent lights and immediately hear a buzzing via your t-coils, you know something is bad somewhere. If you walk under a light and the noise is loudest there, that light probably has a bad ballast. If the ballast is bad, all you need to do is replace the ballast and the interference should stop. However, sometimes it is the lighting wiring itself that was not done correctly. This can cause a ground loop that gives off the buzzing interference. If this is the problem, you’ll need an electrician to re-wire it properly.
Note that loop systems do NOT pick up this interference. It is the t-coils in your hearing aids that pick it up. Too many people blame interference on the loop system because they only hear interference when listening to a loop system—but this is because that is the only time they have their t-coils turned on!