Hello, I play a Yani A901 alto with an A5 V16 M and V16 3's. Whenever I play high C the note gargles as if I was playing underwater. The side C is fine but my teacher says that side C won't do for fast passages and that I should work out my throat positioning to fix it. I've been experimenting and haven't found a solution. I was wondering whether anyone else has had the same problem and what worked for them.