Hands-Free Equalization (BTV): How to Learn It

Hands-free equalization means opening your Eustachian tubes with muscle control alone. There is no pinch, no nose clip doing the sealing work, and no push of air from the chest or tongue. You contract the muscles of the soft palate and upper throat, the tubes open, and air that is already sitting in the back of your nose flows into the middle ear until the pressure matches. Freedivers call it BTV, from the French beance tubaire volontaire, or VTO, voluntary tubal opening. The two names describe the same skill.

The technique is usually credited to the French diver Georges Delonca. It remains the least understood of the common methods. Most of what is known about learning BTV comes from freediving instructors and from divers comparing notes, not from clinical trials. No controlled study has measured how many people can learn it or which drills work best, so treat every timeline and exercise in this guide as practical coaching rather than proven science.

The appeal is simple. BTV frees both hands, keeps you in a clean streamline, and costs almost no effort. The catch is that many divers never get it to work reliably, so it should never replace a solid Frenzel technique as your backup.

Every other named technique relies on moving air or mechanically squeezing the tubes open, and all of them except BTV need the nose sealed. Divers Alert Network lists voluntary tubal opening alongside the others and describes it simply as yawning or wiggling the jaw to open the tubes. The table below puts them side by side. For the deeper treatment of each method, see the full equalization techniques guide.

The key difference is the source of the pressure. Valsalva and Frenzel actively raise the pressure of air in the throat so it forces its way through the tube. BTV does not raise anything. It relies on the air in the throat and nose already being at a higher pressure than the middle ear, which is exactly what happens on descent.

Each Eustachian tube runs from the middle ear, behind the eardrum, down and forward to the back of the nose. At rest the tube is closed. DAN describes the tubes as normally closed, opening briefly each time you swallow or yawn to ventilate the middle ear.

Two muscles near the soft palate do the work. For a freediver the practical point is simple: the tubes open when the soft palate tenses and lifts, the same movement you make at the start of a yawn or during a swallow.

Tensor veli palatini

Tenses the soft palate and pulls on the side wall of the tube. Anatomy research points to it as the main tube opener.

Levator veli palatini

Lifts the soft palate. Thought to assist the tensor, though its direct role in opening the tube is still debated.

Soft palate

The movable back part of the roof of the mouth. Watching it rise in a mirror is one of the few ways to see the BTV muscles working.

BTV is the skill of firing those muscles on purpose, without the rest of a swallow or a full yawn. Swallowing equalizes too, but it is slow and hard to repeat every meter, and a full open-mouth yawn underwater lets water into your mouth. BTV keeps only the part of the movement that matters.

Pressure rises by about one atmosphere for every 10 meters of seawater. As you descend, water compresses your chest, so the air in your lungs, throat and nasal passages stays at roughly the same pressure as the water around you. The middle ear is a rigid air space behind a closed tube, so it lags behind while the water pushes the eardrum inward.

That gives you a pressure gradient pointing the right way. The air behind your nose is at ambient pressure, and the middle ear is below it. Open the tube, and air flows from high to low until the two are equal. Nothing needs to be pushed. This is the whole reason BTV works, and it is also why it feels so much gentler than Valsalva: you are never raising the pressure above ambient, only letting the ear catch up.

The same physics sets BTV's limit. The method depends on having air at ambient pressure in the nasal passages. On deep dives the lungs shrink so far that the supply of air reaching the back of the throat gets small and harder to move, and at extreme depth the airway can lag behind ambient pressure. That is the mechanism behind lung squeeze, and it is also why deep BTV divers often need Frenzel or a mouthfill to keep going.

Some people can open their tubes on demand without ever having been taught. Freediving instructors commonly report that a minority of students discover they already have it, though no reliable figure exists. Before spending weeks on drills, spend five minutes checking. Do these seated, relaxed, with clear sinuses, in a quiet room.

1. 01 —Close your mouth and start a yawn, but stop at the moment the throat widens and the back of the mouth lifts. Do not let the yawn complete.
2. 02 —Listen for a soft click, a crackle, or a brief muffled change in the sound of your own breathing in one or both ears.
3. 03 —Relax, then push your lower jaw forward and slightly down, as if showing your lower teeth, and listen again.
4. 04 —Try combining the two: jaw forward and a small closed-mouth yawn at the same time.
5. 05 —Note which side responds. It is common for one ear to click more easily than the other.

A click on its own is not proof. The better check is to create a small pressure difference and see whether the movement releases it. Pinch your nose and swallow once, a Toynbee, which often leaves the ears feeling slightly full. Let go of your nose and try the closed-mouth yawn or jaw thrust. If the fullness clears without swallowing, the tubes opened.

If you got a faint click, you have something to build on. If you got nothing, the same drills are still the best available route, but go in with modest expectations. Work through these in order. Each one isolates part of the movement so you can feel it before you combine it.

1. The closed-mouth yawn

Start a yawn with the lips sealed and hold the first stage, where the back of the throat widens. Repeat slowly, trying to make that stage smaller and smaller until only the tiny muscular lift remains, with no yawn reflex attached. The aim is to separate the tube-opening part of the yawn from the jaw and chest parts.

2. Jaw thrust forward and down

Slide the lower jaw forward and slightly down, hold two seconds, release. This is the same move used in the Edmonds technique. On its own it opens the tube a little for some people, and combined with the closed-mouth yawn it often produces the first clear click. Keep it gentle. A clenched, aggressive thrust just tires the jaw.

3. Soft palate lift in a mirror

Open your mouth in front of a mirror with a light, press the tongue down, and look at the soft palate and the uvula hanging from it. Start a yawn and watch them rise. Now try to lift them without yawning. When you can lift the palate on command with the mouth open, close the mouth and repeat the same lift blind. This is the closest thing to watching the BTV muscles work.

4. Tongue position

Rest the tongue tip behind the lower front teeth and keep the back of the tongue low. A rising tongue turns the movement into a Frenzel stroke. BTV should happen with a quiet tongue.

5. A light Frenzel as the check

Use a very gentle Frenzel to put a little pressure into the ears, then try to release it using only the palate lift or jaw thrust. If you are wearing a freediving nose clip, you can run this loop repeatedly without your hands: small Frenzel in, BTV out. Each successful release confirms the tubes are opening under your control.

How often to practice

Short and frequent works better than long and rare. A reasonable pattern used by many instructors is a few minutes, two or three times a day, with a total of perhaps 20 to 40 repetitions. Stop if the jaw aches or the ears feel sore. Some divers get a usable BTV in weeks, some take months, and some never get it despite doing everything right. That last group is not doing it wrong: tube anatomy varies between people, and there is no evidence that effort alone guarantees the skill.

Once BTV works reliably on dry land, move it into shallow water under controlled conditions with a buddy. A pool or a calm line in 5-10m is ideal. Start with slow, relaxed descents where the only job is equalizing, and be ready to switch to Frenzel the instant BTV hesitates.

• Equalize early and often. Start just below the surface, before you feel pressure, and repeat every meter or so in the first 10 meters. DAN recommends equalizing every few feet in the early part of a descent.
• Keep the head neutral. Craning the neck back to look down the line stretches the throat and can make the tubes harder to open. A slight chin tuck with the eyes looking forward and down tends to work better.
• Keep Frenzel ready. A nose clip or a mask skirt you can reach keeps the backup available without a pause.
• Descend slowly at first. A fast descent grows the pressure gap faster than a new BTV can close it.
• Stop and rise a meter if an ear lags. Never keep descending on a tube that has not opened.

The payoff shows most clearly at the entry. In a duck dive the first two meters are where pressure changes fastest and where your hands are busy with the pike and the first pull. A diver with BTV can equalize through that phase without breaking streamline, and on a line both hands stay free for free immersion pulls.

BTV is not a universal solution, and treating it as one causes injuries. It depends on healthy, mobile tubes and on air at ambient pressure behind the nose. Take away either and it stops working.

• Congestion. Swollen lining from a cold, allergies or sinus trouble can hold the tubes shut no matter how well the muscles fire.
• Depth. As the lungs compress, less air reaches the back of the throat and BTV loses reliability.
• A gap that already grew too big. A large pressure difference can hold the tube shut. Rise a little before trying again.
• Fatigue, cold and stress. All three blunt the fine palate control BTV needs.

Research on freedivers shows how quickly ear stress accumulates even when divers equalize. In a Diving and Hyperbaric Medicine study, 16 freedivers performed 317 dives to an average of 13.3 meters in a 20 meter pool, and signs of pressure-related change on the eardrum appeared in 48 percent of ears, rising with the number of sessions. The study did not look at BTV specifically, but it is a reminder that repeated descents load the ears whatever technique you use. Deep specialists who want to push past the point where BTV fades should build the mouthfill technique on top of a clean Frenzel.

Most BTV problems come down to one of three things: the movement is not quite the right one, the tubes are not healthy enough to open, or the diver is asking BTV to do something it cannot. The table covers the usual symptoms.

An ear that refuses to clear is not something to fight with BTV. Rise a meter and try again; if it still will not clear, end the dive. If you are still building the basics, the step-by-step guide to how to freedive covers the full descent routine that BTV plugs into.

The rule that matters most: never force an equalization. Pain on descent means the middle ear is losing the race with the water, and continuing down risks middle ear barotrauma, the most common medical problem in diving.

• Stop at pain. Rise, try again gently, and end the dive if the ear will not clear.
• Never dive congested, and do not use a dive to test whether a cold has cleared.
• Know the signs of ear barotrauma: pain, fullness, muffled hearing, a crackling or fluid feeling, and sometimes blood from the nose or in the mask.
• Treat vertigo, ringing, or sudden hearing loss after a dive as urgent, and get medical assessment the same day.
• Never practice breath-holds in water alone, even shallow equalization drills. Train with a buddy who is watching you.

If your ears regularly struggle to clear on land as well as in the water, or one side never equalizes despite good technique, see an ear, nose and throat doctor. Persistent Eustachian tube problems have medical causes that no amount of drilling will fix, and an ENT can examine the eardrum and test tube function. BTV is a refinement for healthy ears, not a treatment for unhealthy ones.

"Pain is not acceptable."