Turbulence kills them, but another thing that I noticed is that the technique also seems to change with depth. I think that it has to do with the resonant frequency of your mouth (your lips and mouth form a little "helmholtz resonator"). This frequency seems to change with depth. When you get the technique just right, you get a very satisfying "thwump" sound -- similar to the sound a stone makes when it plunks into water with a minimal splash.
When you get that sound, you can tell before the bubble even floats into view that it's going to be a good one. Sometimes the bubbles are incredibly stable, and will withstand a lot of turbulance. Also, if you blow one way down (like 30 or 40 ft or so), they expand to ridiculous proportions -- you can easily swim into them and watch the ring from inside.
|
