<<tom775257 So why don't you explode when you surface>>
Sorry to go off topic:
Simply breathe normally on a standard ascent, and allow the pressure to equalise from within your sinuses/ears. Sub-aqua does has the unfortunate side effect of upon ascent, the entire contents of your sinuses ends up out of your nose, all over your face due to the increasing volume of air in your head. This is especially bad if you have a cold..... Seriously though, on a fast ascent you run the risk of damaging your lungs. Regarding pressure and the like: When diving in Egypt, due to getting thirsty under water (water water everywhere, but.....), we used to take capris-sun down with us to drink (a drink in a foil pack), as it had no air in it, it didn't compress, hence no problem.
On a vaguely aeronautical note, our club tried many things to enhance communication under water. The best way by far we found was a pair of the old pneumatic headphones given to PAX. The person you want to talk to puts on the headphones; you blow out the water, then speak through it. Worked very well! I used to have a set attached to my stab jacket.
Cheers, Tom.