Equalisation problems stop more new freedivers from progressing than any other single issue. If you cannot equalise comfortably, you cannot dive deeper — it is that simple. The good news: equalisaion is a learnable skill, and most people can dramatically improve in a few weeks of dry practice.
What Equalisation Actually Does
As you descend, water pressure increases at 1 bar per 10 metres of depth. Your middle ear is an air-filled space connected to your throat via the Eustachian tube. When external pressure rises faster than the pressure in that air space, the eardrum is pushed inward — causing pain, then damage if you force it.
Equalisation is the act of adding air pressure to your middle ear to match the increasing external pressure. You must equalise before you feel discomfort, not after. By the time it hurts, your eardrum is already strained.
Valsalva: The Default Technique
Most people learn Valsalva from scuba diving or from instinct: pinch the nose closed and blow against it. This forces air up the Eustachian tubes from the throat.
Why it works shallowly: At 0–10m, your lungs still have significant volume and pressure. There is residual air to push. Valsalva equalisation at these depths is usually effective.
Why it fails deeper: Below 10–15m, your lungs have compressed significantly. The volume of air available to push up your Eustachian tubes is reduced. Valsalva also risks forcing the Eustachian tube closed under pressure — a condition called a reverse block — which can prevent you from equalising at all and may cause barotrauma if you continue descending.
For freedivers, Valsalva is acceptable for the first 10 metres but should not be used as the primary equalisation technique below that depth.
Frenzel: The Freediver's Technique
Frenzel equalisation uses the tongue as a piston to compress the air in your mouth and throat, pushing it up into the middle ear without involving the lungs at all.
The basic movement: close your glottis (the valve between your throat and lungs — the same action as holding your breath to lift something heavy), pinch your nose, and move your tongue upward and backward as if making a 'K' or 'T' sound. This tongue movement compresses the air trapped above the closed glottis and pops air into the Eustachian tubes.
Dry drill to learn Frenzel:
- Sit upright, relax your jaw
- Close your glottis — you know you have it closed if you try to breathe and nothing moves
- Pinch your nose
- Make a 'K' sound silently — feel your tongue rise toward the back of your palate
- You should feel pressure in your ears
Practice this 20–30 times daily away from water until it becomes automatic. Most people achieve reliable Frenzel in 2–4 weeks of consistent dry practice.
Mouthfill: The Deep Technique
Beyond 30–40m, even Frenzel becomes limited as the airway compresses and there is less gas to work with. The mouthfill technique (also called the BTV or Roaché method) involves filling the oral cavity with air before descending and using only that trapped pocket for all equalisations through the dive.
Mouthfill is an advanced skill covered in Molchanovs Wave 3 courses. Do not attempt it without instruction.
Common Problems
One ear equalises, the other doesn't: Usually an anatomical difference in Eustachian tube size or angle. The harder side may need a head tilt — try tilting your hard ear slightly upward as you equalise.
Equalisation stops working at a specific depth: This typically indicates a congested or inflamed Eustachian tube. Do not dive when congested. Saline nasal rinse the morning before diving helps; xylometazoline (Otrivin) nasal spray is used by some freedivers but should not become a regular crutch.
Pain after the dive: Post-dive ear pain or muffled hearing means you forced a dive without completing equalisation. Rest for 48 hours and see a doctor if it persists.
Equalisation is a technique, not a talent. Train it dry, practise it consistently, and the depth will follow.