How do I know if I use air of the mouthfill to equalize?

[Kray]

instead of air in the lung when trying on land.

 

[Azrael3000]

Simply put your hand on your stomach (diaphragm), if it moves when equalizing you are most likely using your lungs. Another option is to do a forced exhale and then try to equalize, if it works a lot worse (or not at all) compared to a full lung it is also most likely air from your lungs.

 

[Jo_duiker]

Simply put your hand on your stomach (diaphragm), if it moves when equalizing you are most likely using your lungs. Another option is to do a forced exhale and then try to equalize, if it works a lot worse (or not at all) compared to a full lung it is also most likely air from your lungs.

Azrael3000 described (in my opinion) the most important / noticable "by yourself" feature of Frenzel: there's no tension in your stomach when you do Frenzel. With Valsalva: there is very noticable tension!

There are some other things you can check to see whether you do Frenzel, apart from the above.
You are probably doing Frenzel when you can combine several of the following features:

-) your adam's apple is moving while equalizing
-) you can equalize easily with your mouth open
-) you can equalize a lot within a few seconds (like 5 x in 2 sec)

 

[Kray]

yeah I think i'm definitely doing frenzel, but when I tried FRC dives, around 15m, it got pretty difficult. Is it true that once there is air in the mouth + frenzel, one should be able to equalize until the air runs out of mouth ?

 

[Jo_duiker]

yeah I think i'm definitely doing frenzel, but when I tried FRC dives, around 15m, it got pretty difficult. Is it true that once there is air in the mouth + frenzel, one should be able to equalize until the air runs out of mouth ?

Wow, FRC to -15m?! I do full lungs to -15m and my contractions already start on my way down, so when I get to -15m, I turn and race (calmly though, lol) for the surface. I must be doing something wrong. (Like having a lousy swimming and duck dive technique and not relaxing enough).

I guess you have to keep hold of whatever little amount of air you have in your mouth and keep it there, especially in FRC, so: close the epiglottis and keep your mouth closed as well. You NEED air in your mouth to do Frenzel. That's what the whole mouthfill technique is about: at a certain depth, you "transfer" air from your lungs to your mouth and you keep it trapped in your mouth between your closed epiglottis and your closed lips. Could more experienced divers confirm whether I am right about this?

Have fun! (I hope one day I can say I'm doing FRC dives to -15m too!)