Words, music, comment, notes, news, and updates since 1997 from Derek K. Miller, a writer, editor, web guy, drummer, and dad who's a blogger in Vancouver, Canada.
Uhhh, be REALLY careful with that last one. I'd heard of it before from someone in St. John's whose high school teacher demonstrated it - and then promptly passed out because he couldn't exhale the heavier-than-air gas from his lungs! One of the students had the presence of mind to turn him upsidedown. Taught that class a science lesson they'd never forget...
Yeah, that's why he was saying that you shouldn't try it, at home or anywhere else. Even helium can be dangerous, since if you inhale too much and don't get it out of your lungs, you can starve your cells of oxygen, so you could pass out or even die.
So Jeff, no, you shouldn't try it, and sulphur hexafluoride gas is extremely expensive anyway. Better to use some of the vocal filters in GarageBand to get a similar effect.