Cesil,
Welcome to Deeper Blue. If you do a search on my posts you will find that I have been through quiet an ordeal in learning to equalize upside down. I did a lot of studying of the subject, went to two specialists. It’s a definite fact that there are people with more problem than others. One theory is we have more soft tissue that falls down on the Eustachian tubes when we are inverted. Another is hard tissue that the Eustachian tubes fall on.
One likely source is the adenoid tonsil that is removed about 70% of the time in a tonsillectomy. This tonsil is located right next to where the Eustachian tubes enter the pharynx, which makes it likely that an enlarge tonsil from chronic infection would hinder the opening of the Eustachian tube.
There are also other tonsils and possible physical causes, but the good news is that there are two muscles (tensor palatini and levator palatine) which are so efficient at opening the tube that if one learns to voluntary control them, the tubes can be open even with physical problems. In fact several doctors and scientist have speculated that many ear surgeries in children and adults to relieve chronic infections could be avoided if the patients learned to open their tubes by control of these muscles.
Here is copy of another post. I hope it helps,
don
“I had a bad inverted equalization problem, although I had no problem upright and could even do it hand free. I researched it for months and purchased and practiced on an inversion machine. It took me about 8 months to master and I still have to practice twice a week. The moment I think I have it, I will have problems again.
For me the trick was to learn to flex the muscles and open the tubes before I put any air pressure on them. Any air pressure first, and they wouldn’t open when I was inverted. I learned to flex the muscles by employing the theory that if a muscle flexes, even if not by its self (firing muscle tissue) it still send signals to the brain that it is moving and you can learn that feeling and use it to learn to flex the muscle. Basic physical therapy stuff. You know were they retrain someone to use their muscles by manually moving it for them at first?
To do this I stood in front of the mirror and did the Frenzel technique several times, really concentrating on the feeling around the tubes open. Then I kept decreasing the pressure. If I lost the feeling I increased the pressure to regain it. In a few days I was able to fire the muscles and open them without any pressure. Then for inversion it was a quick mater of learning to fire and immediately pressure.”