Feedback is the result of sounds leaking from the hearing aid speaker, often reflecting from an object like a phone, and going back into the microphone, which then becomes amplified to the point where it cannot be amplified any more. A loud, painful squeal or whistle is the result. It’s the same issue found in an auditorium when a microphone is placed too close to a speaker. Many hearing aids on the market today use a mechanical approach when addressing feedback. A tight, oversized hearing aid shell is produced in an attempt to form a tight seal between the hard hearing aid shell and the soft ear canal walls. The result may be an uncomfortable fit and despite the effort, feedback may still occur.