Re: IS this real science or a special effect?

CharlesRCaplan@[EMAIL PROTECTED]
 wrote:

> ... The vibrations travel
>through the air at their normal speed. when you inhale helium and then
>speak the sound of your voice gets higher because the sound of your
>vibrating vocal cords travels faster in helium than in air. With
>sulfur hexafluoride it's the opposite, the sound of your vibrating
>vocal cords travels slower making the sound deeper. ...

The speed of sound through the gas might well be different but it won't
shift the frequency.

I'm not sure, but I presume that the density of the medium actually
alters the frequency at which the larynx vibrates.  Or it might have
something to do with the way that the overtones are filtered.

-- 
Dave Farrance