Electromagnetic interference in hearing aid T-coil applications


  • B. McKinnon Barron Kennedy Lyzun & Associates Ltd., North Vancouver, BC, Canada


electromagnetic interference, hearing aids, hearing aid T-coil applications, electrical interference, noise, telephone handset, induction loop, noise sources


Investigates complaints of high levels of electrical interference experienced by University of British Columbia staff wearing hearing aids in the newly constructed Brock Hall. The architect requested that we try to identify the source of the noise and see if it may be related to a deficiency in the construction of the new facility. The noise was affecting staff members using the T-coil setting on hearing aids. The T-coil is a coil of wire that is switched in place of the hearing aid microphone to allow the hearing aid to pickup the varying magnetic field at the earpiece of a telephone handset. It is essentially one half of a transformer, the other half being provided by the handset or an induction loop in a listening assistance system. We often specify listening assistance systems in our sound system design work for theatres and other public spaces, and we are familiar with a number of typical causes of electromagnetic interference (EMI) in this application. We expected that the noise was being caused by devices such as `Power Smart' type fluorescent ballasts and other conventional electrical noise sources such as transformers and motors. We reviewed a set of electrical drawings to attempt to identify the most likely noise sources

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How to Cite

McKinnon B. Electromagnetic interference in hearing aid T-coil applications. Canadian Acoustics [Internet]. 1994 Sep. 1 [cited 2024 Apr. 23];22(3):79-80. Available from: https://jcaa.caa-aca.ca/index.php/jcaa/article/view/859



Proceedings of the Acoustics Week in Canada