What causes hearing aid feedback?

Acoustic feedback occurs when amplified sound leaks out of the ear canal and is picked up by the hearing aid's microphone, creating a loop: the hearing aid amplifies sound → sound leaks out → microphone picks it up → amplifies it again → repeat. The result is the characteristic high-pitched whistle.

The most common causes are:

• Poor fit: The hearing aid or earmold doesn't seal the ear canal properly, allowing amplified sound to escape
• Earwax buildup: Wax in the ear canal reflects amplified sound back toward the microphone
• Volume too high: Higher amplification increases the likelihood of feedback
• Damaged tubing or dome: Cracks or holes in the tubing or dome allow sound to escape
• Holding something near the ear: Cupping your hand over your ear, hugging someone, or putting on a hat can cause momentary feedback

Step-by-step fixes to try at home

1. Reseat the hearing aid

Remove the hearing aid and reinsert it carefully, ensuring it's fully seated in the ear canal. For RIC/RITE hearing aids, make sure the dome is fully inserted. For BTE hearing aids with earmolds, ensure the earmold is properly seated and the tubing isn't kinked.

2. Check for earwax

Earwax buildup is one of the most common causes of feedback. Check the wax guard (the small filter at the tip of the receiver) and replace it if it's clogged. If you have significant earwax in your ear canal, see your doctor or audiologist for professional removal.

3. Inspect the dome or earmold

Check the dome (for RIC hearing aids) or earmold (for BTE hearing aids) for cracks, tears, or deterioration. A damaged dome or earmold won't seal properly and will cause feedback. Replace the dome if damaged — domes are inexpensive and easy to replace.

4. Reduce the volume

If feedback occurs at high volume settings, try reducing the volume slightly. If you need high volume to hear adequately but feedback occurs at that level, the hearing aid may need reprogramming by your audiologist.

5. Check the tubing (BTE hearing aids)

For behind-the-ear hearing aids, inspect the tubing connecting the hearing aid to the earmold. Cracked or hardened tubing allows sound to escape and causes feedback. Tubing should be replaced every 6–12 months.

When to see your audiologist

If the above steps don't resolve the feedback, contact your audiologist. Persistent feedback may indicate:

• The hearing aid needs reprogramming (feedback management settings need adjustment)
• The earmold no longer fits properly (ear canals change shape over time, especially with weight changes)
• The hearing aid needs repair
• Your hearing has changed and the current amplification level is no longer appropriate

Feedback management technology

Modern hearing aids include sophisticated feedback management systems that detect and cancel feedback before it becomes audible. If your hearing aid has persistent feedback despite a good fit and clean wax guards, ask your audiologist to check and optimize the feedback management settings during your next appointment.