Ok, first of all I play a Jupiter 711RBSO. Lately when I play high notes (I would say around E above the staff and higher) sometimes they sound "shakey." I have a hard time describing it, but that's how they are. I'm note sure what it is... maybe some kind of an undertone coming out along with the note I'm playing? I've looked over my flute and can't find any leaks or anything. I have auditions very very soon and would like to get back to practicing on a fixed flute. Guess I'm going to have to take it to be repaired, but thought maybe you guys could help me out first. Thanks.

the sound

It's difficult to say without seeing/hearing the problem. Perhaps it's not the flute....Are you sure you are supporting, and focusing your air properly? Anyway, I think you were dead on. Taking it to a repair tech is probably the best way to go.

I doubt that it is me... I have been playing for 8 years and in all of my playing I have never come across this problem before.

wait, does it like...hmmm...it's hard to explain
does it sound like it's vibrating somewhere around the bars
well, just trying to help you describe the sound...
good luck!

Something similar happened to me not long ago but it happened with the middle B flat...I tried to get people to hear the sound shake when I played but they couldn't hear it and only I could. So I asked my teacher about it and she said to take it to the shop and get them to check out the cork and the cap that screws on the end.

In MY case, the end cap kept unscrewing a little which made certain notes (which happened to be B flat and a few others) sound shaky. I'm not positive that it will work for you but I WOULD have the flute checked out. And I would tell them to check the headjoint - specifically the cap on the end and the cork.

Good luck.

stupid question, but what's the mechanism???

The mechanism is the part of the flute that moves. This includes key cups, arms, rods, steels...Pretty much all the stuff on the body of the flute besides the tube itself.