I just released a new YouTube video called "What to do when your trumpet part is in the wrong key".
I know what you're thinking: There are no "wrong" keys.
You're right. All the keys are fantastic.
But when you are playing in a band and everyone is playing in a different key than you are, it's going to sound pretty grating. And that is what happened last week when I was handed some sheet music for "Down Yonder."
I could tell that I was not playing the same notes as everyone else, because it sounded awful.
Anyway, this is not the first time this has happened... and I'm sure it won't be the last.
I was able to make an educated guess that the part I had was one whole step lower than what I was supposed to be playing. This video walks you through what I had to do to make it sound right so we could keep playing it.