Well, I guess experiences vary with the individual. My main
point was that if the poster (purple stars) was experiencing
pain trying to free-dive he should be very careful and learn
to equalize the pressure or he would get to learn about
barotrauma from a medical specialist ;-) The time I think
I hurt my ears I was in about 12 feet of water at Stingray
City in Grand Cayman. It was a long time ago, but the
tinnitus is with me still sigh.

PS - I agree with you that its much easier to equalize ascending
rather than descending.

Don W.

Dave wrote:
On Wed, 22 Feb 2006 23:35:10 GMT, Don W
said:


I am, however, trained as a technical diver and remember being
trained (and experiencing) that it is necessary to equalize both
descending and ascending.


I went through the NSDS training and spent several years as a diver,
including SCUBA, Jack Brown, regular hard hat and helium hard hat. Also
spent some time as diving officer and have many hours going both up and down
in a recompression chamber. Both my experience and training tell me that on
ascent the ears clear themselves well before experiencing pain, because the
pressure in the inner ear exceeds that in the throat, and absent something
extremely unusual (which I've never seen) that pressure gets relieved very
much as in my balloon illustration. On the way down, on the other hand, the
pressure buildup tends to close the Eustachian tubes at the entrance to the
throat because the intersection with the throat is very much like the
"duckbill" valve in a marine head. So if you don't know how to open up that
duckbill valve you get low pressure in the inner ear compared to the greater
external pressure on the ear drum.

If a diver's tubes are clogged, he knows it on the way down.


If one or both ears is blocked, and the
pressure difference is enough, a barotrauma or possibly a ruptured
eardrum is the result.

Also, think about it. If what you said is true then people would
not need to equalize during ascent on an airplane. As a pilot I
can tell you that people do very much need to equalize during ascent
in an unpressurized airplane and that if a person does not know how
to equalize a very painful experience is the result.


Again, on the ascent the clearing virtually always occurs automatically well
before the threshold of pain is reached. Whether he knows how to equalize or
not, his ears "pop" when the pressure differential between the throat and
the inner ear is sufficient, because he inner ear is like the inside of that
balloon. I suppose one could get some slight buildup on the ascent if he has
very inflamed tubes. But note that the aircraft situation is the reverse of
diving in that the external pressure is decreasing first, as you ascend, and
increasing as you descend, creating the possibility of having a problem on
the way down when there wasn't a problem on the way up.

Take your kids flying in a small plane sometime when they have a head
cold. Then see if they automatically equalize on the ascent ;-)