Well the trick to prevention of decompression headaches may be to know how long you can hold a loud high note before its release would lead to a headache. Later as one improves his register control he can learn to back off the volume. If the tone still does not project due to amplified or other loud instruments? Can use a microphone. Hopefully one with a good monitor and equalization. I've found that experience helps twofold: A. Learning to pull off a high note phrase before developing too much compression. B. A stronger body does not develop those Slammer headaches so easily.