I've read those posts, but could not find the exact steps (if there are any) to accomplish this in water. Can you please explain the difference?
I think hands free is most probably the most difficult method of equalisation to teach or relay as each person experiences it a bit differently and as it all happens in your head there are no external physical cues to focus on.
I'm by no means an expert and not particularly good at BTV, but I'll try my best and describe the differences between above and underwater as I experience them and tried to figure it out for myself...
When driving over a mountain or when taking off in a plane all I have to do is swallow to in order to equalise the pressure differential.
When sitting still in front of my pc it's bit more difficult, I use a combination of kind of moving my ears and lightly moving my inner throat area. To expand on this: Although it feels as if I'm moving my ears when I do this, while looking in a mirror, they do not move at all - and just for clarity sake, when not attempting to equalise I'm able to move my ears so that its externally visible. Also, when referring to my inner throat, although it feels as if I'm targeting the pharynx and larynx there is no movement there either, so I think this feeling is actually when I target the the two eustachian tube muscles (Levator Veli Palatini Muscle (LVPM) and Tensor Veli Palatini Muscle (TVPM)) which controls the opening and closing of the tube.
When diving, its even more difficult. The action of moving my ears and throat area feels quite a bit more exaggerated. Also compared to Frenzel where I only have to equalise once every 2m or so, with BTV I have to constantly focus on keeping my ears equalised as much as twice or even three times for every meter I descend.
The way I tried to rationalise this to myself, and I may be technically completely off the mark, is on a plane the there is a negative pressure and for me this is easier to overcome, hence a simple swallow will pop my ears.
When sitting in front of the pc practising BTV, there is no pressure differential. So the action becomes more focused and specific in order to achieve the sound of air in my eustachian tube.
Under water there is a positive pressure with a higher pressure gradient. For me this is more difficult to overcome hence the extra effort required to equalise. Underwater there are also al lot of other variables that in my case wreak havoc with focusing exclusively on equalisation, so I tend to be pretty lax when training BTV.
