An Annoying Whistle: No hearing aid is the same. They are fitting to the individual person, to ensure the hearing aid can do its job. If the hearing aid isn’t sitting properly in the ear a whistling sound can happen with movement, or be a persistent part of the day. Your ears might have a wax buildup causing the hearing aid’s displacement, or it might not have been fitted properly. In the case of children, their ears might have outgrown the original hearing aid.