Does anyone besides me notice the pitch drops by a half step or so when you burp while playing? Is it just me or do other people hear the drop in pitch. I’m thinking the extra carbon dioxide in my breath acts differently than regularly exhaled air.
Is the carbon dioxide rich burp air (you won’t find that phrase very often) denser than regular exhaled breath and the sound waves are slowed down like a bug swimming in gravy? I’ve noticed the effect on brass instruments too. But I never burped while playing when somone with an ear happened to be nearby. I havn’t tried recording such a thing either, although I probably should. Probably like trying to photograph a lighting bolt. Hard to do.
Ever- body run get a six pack and start working on this, if you don’t mind.
I’m assuming everyone that has viewed this post is busy working on research.
Yes, I’ve noticed this too. Maybe you could come up with a tune that takes advantage of this. 
It would be interesting to understand the physics behind this.
Bob
Someone called ?
Yes, the pitch change is due to the change in gas composition…different sound velocity…try playing the Helium trick sometime.
urp
shtaaaying in tune, while burping… that’s one of the real tests…
So I should roll in or out depending on the gas composition of the burp?
It’s a good thing we don’t have to deal with methane.
Vomitbunny, I think you have an oral fixation 
Anyway, yes, sound travels more slowly through carbon dioxide, and a burp has more than the usual proportion of CO2 than normal exhaled air (which is already rich in CO2). I did once try playing flute after inhaling a little helium, as Jack mentioned above, and the result is just what you’d expect…the pitch goes way up.
Ah, out is up in pitch.
You have found the test of the true professional.
When you burp, your pich does not move at all; tape your self to convince your self. It’s an illusion due to drop in pressure somewhere
I dont quite understand the physics of it..
Burping Guinness, my pitch used to drop. Well, it sounded to me as if it did. Now it doesn’t. Well, it sounds to me as if it doesn’t. I remain clueless.
Glad to be of help.
This happens with the whistle..i’ve often noticed the pitch dropping immediately after a burp.
But it’s just your own ears that hear it and the pitch doesn’t actually drop? I’ll have to go get more beer to test this theory.
No, the pitch actually drops…and there’s no substitute for an actual experiment (send a few Guiness this way while you’re at it)
Oh I drink the cheap stuff. Leaves more money for flutes and whistles and such. If anything it makes you burp more. In the name of science.
If you consume a more appropriate diet, you will not have these problems.
I think it does actually drop, because people playing with me in sessions have noticed me suddenly getting flat.
However I have noticed that when I’m listening to music and I yawn, the pitch drops too. I suspect that has to do with the effect of stretching my eardrums when I yawn?
when you burp, your energy level drops. it’s a sign your body needs nurishment,
either food or drink.
if you don’t do that, you’re body has to compensate in one way or another has to struggle back to normal. Vomitbunny would agree with me here, the first option’s best.
And when gas comes out the other end, it creates a force field that causes chairs to slide away from you. Sort of like that girl did in Fantastic Four.
I believe there’s a direct proportion between pitch perception and pitch reality as related to pints of Guiness consumed. 
BTW, you want real burps, try Diet Coke! Whoo-hoo!