Tube and Dome Size Helps Hearing Aids Fit Properly

Proper Physical Fit for BTE Hearing Aids

One of the first steps to ensure that Behind-the-Ear or BTE hearing aids produce optimal results is making sure that they are fitted properly on and in your ears. This can be accomplished by the correct combination of the tubes and domes on your hearing aids.

The sound from a BTE hearing aid is delivered into the ear canal through a tube with a mushroom-shaped dome on the end of it. The availability of various sizes of these two user replaceable parts gives BTE style hearing aids the ability to physically fit ears of all sizes. This is an important consideration due to the wide variety of ear sizes out there in the world. Big people's ears can be bigger than little people’s, and some people might even have ears of different sizes. However, the point is that no matter what size your ear is, a proper physical fit is possible and necessary.


The pre-bent tube and dome assembly serves the purpose to not only deliver the BTE’s output sound into the ear but to also hold the BTE in place on the ear. The tube connects to the BTE just behind where the ear connects to the scalp. Properly fit, the tube should follow the contour of the ear so it fits against the skin until it curves into the top of the ear canal opening.  The pre-bent tube should be snug but not tight.

  • If the area at the top of the ear or ear canal becomes tender within the first few hours of wearing the hearing aid, it indicates that the tube is too short.
  • If you can feel the hearing aids move with normal head movements or if the tube has a tendency to slip out of the ear canal, the tube is too long.

Tubes are generally available in short, medium, and long lengths and can be generally approximated to a person's height.

  • Short tubes - Children and small or shorter-sized people
  • Medium tubes - Average-sized adults with average sized ears
  • Long tubes – Tall people


Dome is the generic name for the removable end-piece that fits on the canal end of the tube. Most domes are mushroom-shaped, hence the name, and come with holes in the skirt.

Domes are soft and shaped to make placing the tube in the ear canal easy and comfortable. Their shape also helps hold the tube steady once it’s in the ear canal.

Domes need to be slightly larger in diameter than the ear canal to stay in place.

  • Even though domes are soft and pliable, wearing one that is too large will quickly become uncomfortable.
  • Wearing domes of a smaller diameter than the ear canal allows movement, which can cause unwanted lip-smacking noises with jaw movement, swallowing, etc.

Domes come in a variety of diameters and their proper fit is a balance between comfort and the BTE’s stability in and on the ear. You may need to try a few different sizes to find the balance that works best for you. It is not uncommon for new wearers to move to a larger diameter dome after wearing the hearing aids a few months.

How are Open and Closed domes different from each other?

  • An open dome (big holes in the skirt) makes speech sounds sharper at normal conversational volumes. Open domes allow much of the sound from low frequencies, usually noise, to bounce out of the ear canal just as it does naturally. Feedback, or squealing, can occur at a lower overall volume with an open dome than with a closed one with smaller diameter or no holes in the skirt.
  • Closed domes hold more sound energy in the ear canal than open domes do. This means that the user will perceive a higher volume with closed domes than with open domes at the same volume control setting. Closed domes give the wearer more room to turn up the hearing aid overall volume before feedback becomes a problem. Some closed domes have overlapping pedals instead of a full skirt, these are called Tulip domes.

We recommend experimenting with the extra domes supplied with your new hearing aids. Use the following as a starting point;

  • Noticeable Hearing Loss = Open domes
  • Moderate Hearing Loss = Open domes but possibly with smaller holes
  • Severe Hearing Loss = Closed domes
  • Profound Hearing Loss = Custom ear molds (call or email us for more information about this option)

A quick note about hearing aid feedback - It is caused when sounds leave your ear and then find their way back into the hearing aid microphone. There, they are re-amplified which causes the hearing aid to squeal, whistle or chirp. Feedback can occur when you put your hand up to your ear, when you’re hugging someone, while you’re inserting/removing your hearing aid, or when something comes within a few inches of your ear. Sometimes it can even occur when there is too much volume being fed into the ear from the hearing aid and then leaving via open domes.

BTE hearing aids not only fit the best due to their flexible range of options in tube and dome sizing, but they are also the easiest to maintain long-term as well.

Good luck on your journey to better hearing and look for a future message with more information that you need to hear well and protect your investment.

Thanks for reading!