Ear Equalization: Why the Shallowest Part Is Often the Hardest

For both freediving and scuba diving, the shallowest part of the descent is where pressure changes most rapidly in relative terms. This is why beginners often need to equalize most frequently near the surface.
Equalization ultimately addresses the pressure difference across the eardrum. But to understand why shallow water is so demanding, it helps to focus on what increasing pressure does to the relative volume of trapped gas.
If you want to develop a reliable Frenzel equalization, it also helps to understand the other major methods—Valsalva, hands-free BTV, and Mouth Fill—and how they differ in muscle use, airway control, and application.
1. Why Is the Shallowest Water Often the Hardest Place to Equalize?
Start with a simple example. At the surface, assume a closed gas space has a relative volume of 1 at approximately 1 ATA.
At around 10 metres, ambient pressure is about 2 ATA. Under Boyle’s law, assuming other conditions remain approximately constant, that gas volume becomes about 1/2. In only the first 10 metres, the gas volume has therefore decreased by roughly 50%.
Continue to 20 metres, where pressure is about 3 ATA, and the relative volume becomes about 1/3. The additional volume change from 10 to 20 metres is only 1/2 minus 1/3, or 1/6—far smaller than the 1/2 change in the first 10 metres.
As depth increases, the same pattern continues. Absolute pressure becomes much greater, but the relative volume change produced by each additional metre becomes progressively smaller.
For a beginner, this means the first few metres demand early, gentle and frequent equalization. Struggling there does not mean you are unsuited to freediving; you are working in the part of the descent where relative gas-volume change is fastest.

2. Why Do Scuba Divers Often Learn Equalization Quickly While Freedivers Get Stuck?
A useful concept here is body awareness—the ability to connect an instruction with a familiar physical sensation.
Learning an equalization technique means learning to control muscle groups that we rarely isolate consciously. Coaching cues, sounds and everyday analogies are all attempts to help you recognize the correct sensation.
Valsalva is comparatively intuitive because most people already know a similar action from trying to blow their nose while congested. Pinching the nose and gently pressurizing from the torso often produces an immediate sensation of the ears opening.
Frenzel is different. It requires finer separation and coordination of the tongue, tongue root, soft palate, glottis and throat. Some people find that sensation immediately; others need much longer.

3. What Is the Best Way to Learn Frenzel?
There is no single cue that works for everyone.
Language, habits, previous physical experiences and the way a person interprets an instruction all affect whether a particular exercise creates the right sensation. A cue that works instantly for one diver may do nothing for another.
Practice itself changes control. With repetition, the nervous system becomes better at recruiting and coordinating muscles that previously were difficult to isolate.
A mature Frenzel is not simply one hard push. It involves coordinated control of the glottis, soft palate, tongue, throat and gas transfer. When those actions become automatic rather than consciously sequenced, the technique becomes much more reliable.
So the most useful approach is to keep testing cues, notice the differences between muscle patterns, and continue practising until the correct coordination becomes automatic.

4. Why Learn the Other Equalization Methods?
Practice without understanding can still help, but it creates a common problem: the ears pop, so the diver assumes they have performed Frenzel.
That conclusion may be wrong. A successful pressure change only tells you that equalization occurred; it does not identify which muscles produced it.
The four main methods discussed here are Frenzel, Valsalva, BTV and Mouth Fill. Understanding their differences makes practice much more deliberate.
5. Frenzel vs Valsalva: The Key Difference Is the Pressurizing Muscles
These two techniques are easily confused because both can be performed while pinching the nose, and both can create the familiar sensation of the ears opening.
In Frenzel, the decisive pressurizing action is generated mainly by structures above the chest: the tongue, tongue root and throat region compress the gas in the upper airway. The important question is not whether the chest moves at all, but which muscles generate the actual pressure pulse.
Valsalva relies much more on pressure generated by the respiratory system and torso, including the chest, diaphragm and abdominal musculature, to push air upward from the lungs.
This distinction becomes important during head-down freediving. As depth increases, lung gas is compressed and there is no scuba regulator continuously replenishing breathing gas. Relying on torso pressure to move lung gas toward the head therefore becomes progressively less effective.

6. BTV: Hands-Free Equalization
The most obvious visual difference with BTV is that the diver does not need to pinch the nose.
Instead of first building pressure and using it to open the Eustachian tubes, BTV relies on voluntary muscular opening of the tubes themselves. Many divers search for the sensation by recalling the way the ears open during a yawn.
A useful conceptual contrast is: Frenzel is closer to 'build pressure to open the door,' while BTV is closer to 'actively open the door.'

7. Mouth Fill: An Extension of Deep Equalization Skills, Not a Replacement for Frenzel
Mouth Fill is sometimes misunderstood as a completely separate technique that replaces Frenzel. In practice, the two are closely related.
While gas can still be brought up from the lungs, the diver transfers a reserve into the mouth and upper airway. This is why a pronounced expansion of the cheeks is often visible during a Mouth Fill.
As the descent continues, that stored gas is compressed. The diver must manage the reserve, the soft palate, glottis, tongue, cheeks and Eustachian-tube state with increasing precision.
When very little usable gas remains, fine Frenzel-type pressurization can still be important. A reliable Frenzel foundation is therefore highly valuable before progressing to Mouth Fill.

8. Why Do Elite Divers Still Appear to 'Equalize' at Great Depth?
If relative gas-volume change becomes smaller with depth, why can we still see elite freedivers making tiny movements with the cheeks, jaw or mouth far below the surface?
The key is to distinguish between creating a new equalization and maintaining an already established pressure and gas-management state.
In shallow water, rapidly changing ambient pressure requires frequent compensation. At great depth, another problem becomes increasingly important: preserving and controlling the limited gas already transferred into the mouth and upper airway.
9. Sustained Pressure and Pulsed Pressure
One way to understand the distinction is to imagine holding half a mouthful of water without swallowing. Maintaining a static state for a long time can become difficult as swallowing reflexes and muscle fatigue appear.
In deep equalization, sustained pressure means maintaining a relatively continuous pressure and muscular configuration. Pulsed pressure uses very small repeated adjustments to maintain control of the gas and pressure state.
When analysing close-up footage of elite divers such as Alexey, the interesting detail is therefore not simply that the face is still moving. It is the fine control of the cheeks, tongue, mouth and throat as the diver manages a very limited gas reserve.
Conclusion: Know What Your Body Is Actually Doing
Once the techniques are viewed together, several apparent contradictions become easier to understand.
Shallow water is demanding because relative gas-volume change is fastest there. Valsalva is often learned quickly because its muscular pattern resembles familiar everyday actions, while Frenzel requires finer neuromuscular separation and coordination.
BTV and Mouth Fill are worth understanding even if you do not use them immediately, because they reveal different ways of opening the Eustachian tubes, generating pressure and managing gas.
The real goal is not simply to make your ears pop. It is to know which muscles moved, where the gas was, and why the equalization worked. When that understanding becomes automatic physical control, the technique has truly become part of your diving.